--- title: Libraries ... # Wireguard, Tailwind, and identity Wireguard is a secure vpn. Tailwind is peer to peer built on Oauth2 and Wireguard. Lacks peering through NAT facilities, though this is probably not hard to fix or add. The Tailwind server just tells both peers to start pinging each other simultaneously, and tells each peer when the other peer has acked a meeting time. With most nats, the first ping to arrive after a ping has been sent will get through. Wireguard has a provision to keep on pinging. If a peer has a stable IP and port accessible from the internet, it does not ping. The other guy has to ping. If he does not ping for a while, the connection may stop working. If the peer with the stable IP and port finds it cannot get through, discards the connection information, but if it never attempts to use that information, it may hang around for a very long time. Oauth is a generic interface to identity protocols. Anyone can implement Oauth in any way. The Zooko identity model is that each party has his own mapping between non unique Zooko human readable, typeable, and memorable names, and globally unique non human memorable, non human typeable, public keys. We put on top of that a consensus mapping, which is mutable. The end user sees his local name for an identity, that identity's name for itself, and a recent consensus human readable human typeable name for that identity. For major and important widely known identities these should all be the same, and the end user should see a single short human readable name. If the end user sees two or three different human readable names for a counterparty, there is likely to be an issue. If he sees three different human readable names, plus the public key, definitely an issue. The end user's mapping from local petnames to global keys is locally unique, and mutable at the end user's discretion. The consensus mapping is mutable by consensus. For friends who are well known to himself, but not well known to others, the global consensus name may merely be a distraction, and he may turn it off. If someone is on his buddy list, people whitelisted the global consensus name is turned off, unless it is the same, in which case it is turned on, and if the consensus changes, the end user sees that change. # Existing cryptographic social software Maverick says: [Manyverse]:https://www.manyver.se/ {target="_blank"} [Scuttlebutt]:https://staltz.com/an-off-grid-social-network.html {target="_blank"} If looking for something to try out that begins to have the right shape, see [Manyverse] that uses the [Scuttlebutt] protocol. Jim is fond of Bitmessage and it is quite secure, but it has a big weakness in that it needs to flood every message to all nodes in the world so everyone can try their private key to see if it works for decryption. That won't scale. (Can't avoid passing every message on to all callers even if you know it's yours, as you don't want to let someone snooping see that you absorbed a message which is an information disclosure.) Instead [Manyverse] and [Scuttlebutt] allow for publishing and reputation for a public key. The world can see what a key (its author really) publishes. Can publish public posts like a blog, signed by the private key for authenticity and verifiability. Also can publish private messages (DMs), visible to the world but whose contents are encrypted. Weakness in private messages is that the recipient public key is visible on the message - good for routing and avoiding testing every message, bad for privacy. Would be better to have a 3rd mode, private for "someone" but you have to test your private key to see if it's for you. That should not be hard to add to [Scuttlebutt] and [Manyverse]. Reputation is similar to what Jim has proposed: You can specify a list of primary keys/people (friends) you want to listen to and watch. You can also in the interface specify how many degrees of separation you want to see outward from your friends - the public messages from their friends and friends' friends. Presumably specifying 6 degrees gets you Kevin Bacon and the rest of the [Manyverse]. You can also block friends' friends so their connections are not visible to you - so if you don't like a friend's friend you at least don't have to listen any more. Another advantage is that [Manyverse] works in a sometimes-connected universe: Turn off your computer or phone for days, turn back on, catch up to messages. You realy don't even have to be on the public Internet, you could sneakernet or local/private-net messages which is nice for, say, messaging in a disaster or SHTF scenario where you have a local wifi network while the main network connections are down. Bitmessage has a decay/lifetime for messages that means you need to be connected at least every 2-3 days. Biggest weakness is hosting. Your service can be hosted by 3rd parties like any service, and you can host your own. Given the legal landscape as well as susceptibility to censorship via DDoS and hack attacks, you want to have your own server. There are some public servers but sensibly they don't want a rando or glowie from the net jumping on there to drop dank memes. But hosting is nontrivial to carve out your own network bubble that can see the Internet (at least periodically) while being fully patched and DDoS resistant. Of course missing from this from Jim's long list of plans are DDoS protection, a name service that provides name mapping to key hierarchies for messaging and direct communications, and a coin tie-in. But [Manyverse] at least has the right shape for passing someone a message with a payment inside, while using a distributed network and sometimes connection with store-and-forward to let you avoid censorship-as-network-damage. A sovereign corporation can also message publicly or privately using its own sovereign name and key hierarchy and private ledger-coin. The net is vast and deep. Maybe we need to start cobbling these pieces together. The era of centralized censorship needs to end. Musk will likely lose either way, and he's only one man against the might of so many paper tigers that happen to be winning the information war. # Consensus I have no end of smart ideas about how a blockchain should work, but no actual blockchain. Smart ideas are worth two cents a bale, but only if already baled. Need to port in someone else's blockchain code, with a bridge to their blockchain. Then I can make a start on implementing my bright ideas as part of working code. [Near]:https://near.org/papers/the-official-near-white-paper/#introduction {target="_blank"} [Near] is actually implementing no end of things that I have been thinking about, so seems like a good fit. # Git submodules Libraries are best dealt with as [Git submodules]. [Git submodules]: https://github.com/psi4/psi4/wiki/External-subprojects-using-Git-and-CMake [build libraries]:https://git-scm.com/book/en/v2/Git-Tools-Submodules Git submodules leak complexity and surprising and inconvenient behaviour all over the place if one is trying to make a change that affects multiple modules simultaneously. But having your libraries separate from your git repository results in non portable surprises and complexity. Makes it hard for anyone else to build your project, because they will have to, by hand, tell your project where the libraries are on their system. When one is developing code, you normally have a git branch. But the git commit of the master project in which the submodule is contained does not notice its subproject has changed, unless the subproject head has changed. And the subject project head will not change if it points to a name, rather than to a particular commit. For ones changes to a submodule to be reflected in the master project in any consistent or predictable way, the submodule has to be in detached head mode, with the head pointing directly to a commit, rather than pointing to a branch that points to a commit. You will import a submodule from someone else's project, but eventually you and your team are going to make minor changes to it to customize it to your project. In which case you will need your own remote team repo, in place of the original other team's repo. Construct the copied remote repositories so that their default branch is your tracking branch, not the upstream branch. ``` bash git init --bare -b «our_branch» ``` Then, in your local repository where you created the new branch, reset the remote in your local repository to the new remote by editing `.gitconfig` and push «our_branch» from your local in which you created your team's new submodule branch to the remote. or ``` bash git clone --bare «their_remote» -b«their_stable_branch_or_release_tag» cd «our_new_remote» git symbolic-ref HEAD refs/heads/«our_new_branch» ``` If you fail to set your remote to your team's default branch, then your local repositories will keep getting reset back to their team's branch, and chaos ensues. When moving the remote of a submodule in your local repository (usually from their team's remote to your team's remote) you update `.gitmodules` in your superproject, and in each submodule that has submodules of its own, then ```bash git submodule update --init --recursive --force git submodule foreach --recursive 'git status && git switch «our_branch» && git status && git remote -v && git switch --detach' ``` Your submodule remotes propagate from `.gitmodules` file of your superproject, and their branch propagates from the superproject *and* from the remote default branch. And the branch will *also* propagate from `.gitmodules` if `branch = ...` is set. Because git is a distributed archive, it is perfectly possible, and often necessary, to work with all these set to different values, *provided* that everyone is mindful that they are set to different values, and the consequences and implications of them being set to different values. Which consequences and implications get complicated, unobvious, difficult to predict, and surprising when you are working with submodules. Git commands in master project do not look inside the subproject. They just look at the subprojects head. This means that signing off on changes to a submodule is irrelevant. One signs off on the master project, which includes the hash of that submodule commit. When one is changing submodules for the use of a particular project, making related changes in the master project and submodules, one should not track the changes by creating and updating branch names in the submodule, but by creating and updating branch names in the containing module, so that the commits in the submodule have no name in the submodule, the submodule is always in detached head state, albeit the head may be tagged. Names in submodules are primarily of value for amendments to the submodule as an independent module, intended to be used by multiple projects, and for this purpose, tags are better than branch names. wxWidgets releases are identified by tag, not by branch, and the names of branches are only used to communicate a particular project on the submodule to other people working on that project as their master project. Branch names within a submodule, though very useful when you working on a submodule, are not useful to the project as a whole, and except for the primary fork name, should be temporary and local., not pushed to the project repository, But when you are modifying the submodules in a project as a single project, making related changes in the module and submodule, the shared names that are common to all developers belong in the primary project module,and when you have done with a submodule, ```bash git switch --detach ``` From the point of view of the containing superproject, submodule commits are nameless with detached head, except when you are working on them, the name in primary module naming a group of related commits in several submodules, which commits do not receive independent names of their own, even though the commits have to be made within the submodule, not in the containing module which names the complete set of interrelated commits. The submodule commits may well belong to different branches and tags in the superproject, but the submodules know nothing of superproject names, and the superproject knows nothing of submodules names. The primary build should invoke the submodule build, which *will* check each file in the submodule for changes, only when the submodule detached head has changed. And therefore, you want it to change, you want the submodule head to be nameless and detached, whenever you modify a submodule as part of a larger project where you test your changes by rebuilding the whole project to make sure all your related changes fit together. When tracking an upstream submodule that has submodules of its own, which have their own upstreams Update your version with ```bash git pull upstream --recurse-submodules=on-demand «their-latest-release» ``` Make sure things still work. Get everything working. (You do have unit test, right?) When you are working a submodule, your branch has to have a name, or when you push it and pull it, strange things will happen. But the superproject pushes and pulls by commit, not by name, so when you are done, then: git submodule foreach --recursive 'git push` ```bash git submodule foreach --recursive 'git switch --detach' git submodule foreach --recursive 'git push` ``` As its own thing, a submodule has branches with names. As a component of a superproject, it has nameless commits. If you are in a submodule directory of the superproject, and you push and pull, what you are pushing and pulling had better have a name, or else unpleasant surprises will happen. If you are in the superproject directory and pushing and pulling the whole thing, that commit better be detached. You pull a named release of the project that is a submodule of your project from `upstream`, diddling with it to make it work with your project, then you push it to `origin` under its own name, the you detach it from its name, so the superproject will know that the submodule has been changed. All of which, of course, presupposes you have already set unit tests, upstream, origin, and your tracking branch appropriately. Even if your local modifications are nameless in your local submodule repository, on your remote submodule repository they need to have a name to be pushed to, hence you need to have a tracking branch in each of your remote images of each of your submodules, and that tracking branch will need to point to the root of a tree of all the nameless commits that the names and commits in your superproject that contains this submodules point to. You want `.gitmodules` in your local image of the repository to reflect the location and fork of your new remote repository, with your remote as its `origin` and their remote as its `upstream`. You need an enormous pile of source code, the work of many people over a very long time, and GitSubmodules allows this to scale, because the local great big pile of source code references many independent and sovereign repositories in the cloud. If you have one enormous pile of source code in one enormous git repository, things get very very slow. If you rely someone else's compiled code, things break and you get accidental and deliberate backdoors, which is a big concern when you are doing money and cryptography. When your submodules are simply your copy of someone else code, it gets little bit messy. When you change them, it gets messier. And visual studio's handling of submodules is just broken and buggy. A command that works in git-bash will produce unexpected surprising, and unpleasant results in visual studio's git. I really need to give up on visual studio, it is closed source code, and turning bad. When one developer makes minor changes in submodule to make it work with the whole project on which several developers are working on, no end of mysterious grief ensues, because strange and curiously difficult to identify differences appear between builds that Git would normally ensure are the same build. Submodules are a halfway house between completely absorbing the other party's code into your code, and using it as a prebuilt library. Instead, we have walls dividing the project into pieces, which is a lot less grief than on big pile of code, but managing those walls winds up taking a lot of time, and mistakes get made because a git commit in a project with submodules that have changed does not mean quite the same thing, nor have quite the same behaviour, as git commit in a project with unchanging submodules. But then truly integrating a project that is the product of a great deal of time by a great many of people, and managing it thereafter, is likely to take up a great deal more time. Git Submodules is hierarchical, but source code has strange loops. The Bob module uses the Alice module and the Carol module, but Alice uses Bob and Carol, and Carol uses Alice and Bob. How do you make sure that all your modules are using the same commit of Alice? Well, if modules have strange loops you make one of them the master, and the rest of them direct submodules of that master, brother subs to each other, and they are all using the same commit of Alice as the master. And you should try to write or modify the source code so that they all call their brother submodules through the one parent module above them in the hierarchy, that they use the source code of their brothers through the source code of their master, rather than directly incorporating the header files of their brothers at compile time, albeit the header file of the master that they include may well include the header of their brother, so that they are indirectly, through the master header file, including the brother header file. # Git subtrees Git subtrees are an alternative to submodules, and many people recommend them because they do not break the git model the way submodules do. But subtrees do not scale. If you have an enormous pile of stuff in your repository, Git has to check every file to see if it has changed every time, which rather rapidly becomes painfully slow if one is incorporating a lot of projects reflecting a lot of work by a lot of people. GitSubmodules means you can incorporate unlimited amounts of stuff, and Git only has to check the particular module that you are actually working on. Maybe subtrees would work better if one was working on a project where several parts wer e being developed at once, thus a project small enough that scaling is not an issue. But such projects, if successful, grow into projects where scaling is an issue. And if you are a pure consumer of a library, you don't care that you are breaking the git model, because you are seldom making synchronized changes in module and submodule. The submodule model works fine, provided the divisions between one submodule and the next are such that one is only likely to make changes in one module at at time. # Passphrases All wallets now use random words - but you cannot carry an eighteen word random phrase though an airport in you head Should use [grammatically correct passphrases](https://github.com/lungj/passphrase_generator). Using those dictionaries, the phrase (adjective noun adverb verb adjective noun) can encode sixty eight bits of entropy. Two such phrases suffice, being stronger than the underlying elliptic curve. With password strengthening, we can randomly leave out one of the adjectives or adverbs from one of the passphrases. # Polkadot, Near, substack and gitcoin It has become painfully apparent that building a blockchain is a very large project. Polkadot is a blockchain ecosystem, and substack a family of libraries for constructing blockchains. It is a lot a easier to refactor an existing blockchain than to start entirely from scratch. [Near] is way ahead of me, because not suffering from not invented here syndrome. Polkadot is designed to make its ecosystem subordinate to the primary blockchain, which I do not want - but it also connects its ecosystem to bitcoin by De-Fi (or promises to do so, I don't know how well it works) so accepting that subordination is a liquidity event. We can fix things so that the tail will wag the dog once the tail gets big enough, as China licensed from ARM, then formed a joint venture with ARM, then hijacked the joint venture, once it felt it no longer needed to keep buying the latest ARM intellectual property. Licensing was a fully subordinate relationship, the joint venture was cooperation between unequal parties, and now ARM China is a fully independent and competing technology, based on the old ARM technology, but advancing it separately, independently, and in its own direction. China forked the ARM architecture. Accepting a fully subordinate relationship to get connected, and then defecting on subordination when strong enough, is a sound strategy. [Gitcoin]:https://gitcoin.co/ "Build and Fund the Open Web Together" And talking about connections: [Gitcoin] Gitcoin promises connection to money, and connection to a community of open source developers. It is Polkadot's money funnel from VCs to developers. The amount of cash in play is rather meagre, but it provides a link to the real money, which is ICOs. I suspect that its git hosting has been co-opted by the enemy, but that is OK, provided our primary repo is not co-opted by the enemy. # Installers Wine to run Windows 10 software under Linux is a bad idea, and Windows Subsystem for Linux to run Linux software under Windows 10 is a much worse idea – it is the usual “embrace and extend” evil plot by Microsoft against open source software, considerably less competently executed than in the past. ## The standard gnu installer from source ```bash ./configure && make && make install ``` ## The standard cmake installer from source After long and arduous struggle with CMake, I concluded: That it is the hardest path from MSVC to linux. That no one uses it as their first choice to go from linux to windows, so it is likely to be a hard journey in the other direction. I also found that the CMake scripting language was one of those accidental languages. CMakeLists.text was intended as a simple list of every file. And then one feature after another was added, ad hoc, with no coherent plan and vision, and eventually so many features as to become Turing Complete, but like most accidental Turing complete languages, inconsistent, unpredictable, and the code entirely opaque, and the whole way the developers did not want their language to be used as a language. CMake has gone down the wrong path, should have started with a known language whose first class types are strings, list of strings, maps of strings, maps of named maps of strings, and maps of maps, and CMake should create a description of the build environment that it discovers, and a description of the directory in which it was run in the native types of that language, and attempt to create a hellow world program in that language that invokes the compiler and the linker. Which program the developer modifies as needed. That MSVC's embrace of cmake is one of those embrace and extend weirdness's, and will take you on a path to ever closer integration with non free software, rather than off that path. Either that or the people integrating it were just responding to an adhoc list of integration features. That attempting a CMake build of the project using MSVC was a bad idea. MingGW first, then MingGW integrated into vscode, in an all choco windows environment without MSVC present. ```bat choco install mingw pandoc git vscode gpg4win -y ``` That Cmake does not really work all that well with the MSVC environment. If we eventually take the CMake path, it will be after wc and build on MingGW, not before. ## The standard Linux installer `*.deb` `debhelper` and `dh-make` provide a somewhat user friendly tool for making deb files. `*.deb` files are commonly built from `*.dsc` files, which are also available in the repository. Which gives you the option, under debian, of building your entire toolchain, something not possible in windows. It is half way to the goal of building your own linux from scratch, without the elaborate process where you type in a hundred commands, and if you mistype a single one of them, everything goes to hell and you do not know where in the process you went off the rails. But if you want people to build from source, you probably want them to develop, in which case git is better than `*.dsc` files The standard deb file builder integrated into debian is `git-buildpackage`. But other systems like a `*.rpm` package, which is built by `git-buildpackage-rpm` But desktop integration is kind of random. Under Mate and KDE Plasma, bitcoin implements run-on-login by generating a `bitcoin.desktop` file and writing it into `~/.config/autostart` It does not, however, place the `bitcoin.desktop` file in any of the expected other places. Should be in `/usr/share/applications` The wasabi desktop file cat `/usr/share/applications/wassabee.desktop` is ```config [Desktop Entry] Type=Application Name=Wasabi Wallet StartupWMClass=Wasabi Wallet GenericName=Bitcoin Wallet Comment=Privacy focused Bitcoin wallet. Icon=wassabee Terminal=false Exec=wassabee Categories=Office;Finance; Keywords=bitcoin;wallet;crypto;blockchain;wasabi;privacy;anon;awesome;qwe;asd; ``` To be in the menus for all users, should be in `/usr/share/applications` with its `Categories=` entry set appropriately. Wasabi appears in the category `Office` on mate. But what about the menu for just one user? The documentation says `~/.local/share/applications`. Which I do not entirely trust. ### autotools Has a poorly documented and unexplained pipeline to `*.deb` files. Plausibly `cmake` also has a pipeline, but I have not found it. autotools is linux standard, is said to have a straightforward pipeline into making `*.deb` files, and everyone uses it, including most of your libraries, but I hear it cursed as a complex mess, and no one wants to get into it. They find the far from easy `cmake` easier. And `cmake` runs on all systems, while autotools only runs on linux. I believe `cmake` has a straightforward pipeline into `*.deb` files, but if it has, the autotools pipleline is far more common and widely used. ## The standard windows installer Requires an `*.msi` file. If the install is something other than an msi file, it is broken. [Help Desk Geek reviews tools for creating `*.msi`]: https://helpdeskgeek.com/free-tools-review/4-tools-to-create-windows-installer-packages/ {target="_blank"} [Help Desk Geek reviews tools for creating `*.msi`] 1. First and formost, Nullsoft Scriptable Install System (NSIS) Small, simple, and powerful. 1. Last and least Wix and Wax: it requires the biggest learning curve. You can create some very complex installers with it, but you’ll be coding quite a bit and using a command line often.\ And word on the internet is that complex installs created with Wix and Wax create endless headaches and even if you get it working in your unit test environment, it then breaks your customer's machine irreversibly and no one can figure out why. ### [NSIS] Nullsoft Scriptable Install System NSIS can create msi files for windows, and is open source. [NSIS]:https://nsis.sourceforge.io/Download {target="_blank"} [NSIS Open Source repository]:https://sourceforge.net/projects/nsis/files/NSIS%203/3.08/RELEASE.html/view {target="_blank"} [NSIS Open Source repository] People who know what they are doing seem to use this open source install system, and they write nice installs with it. Unlike `Wix`, I hear no whining that any attempt to use its power will leave you buggered and hopeless. When I most recently checked, the most recent release was thirty five days previous, which is moderately impressive, given that their release process is somewhat painful and arduous. ### Wix `Wix` is suffering from bitrot. The wix toolset relies on a framework that is no longer default installed on windows, and has not been for a very very long time. But no end of people say that sucky though it is, it is the standard way to create install files. [Hello World for Wix]:https://stackoverflow.com/questions/47970743/wix-installer-msi-not-installing-the-winform-app-created-with-visual-studio-2017/47972615#47972615 {target="_blank"} [Hello World for Wix] is startling nontrivial. It does not default create a minimal useful install for you. So even if you get it working, still looks like it is broken. [Common Design Flaws]:https://stackoverflow.com/questions/45840086/how-do-i-avoid-common-design-flaws-in-my-wix-msi-deployment-solution {target="_blank"} [Common Design Flaws] do not sound entirely like design flaws. It sounds like it is easy to create `*.msi` files whose behaviour is complex, unpredictable, unexpected, and apt to vary according to circumstances on the target machine in incomprehensible and unexpected ways. "Works great when we test it. Passes unit test." [Some practical Wix advice]:https://stackoverflow.com/questions/6060281/windows-installer-and-the-creation-of-wix/12101548#12101548 {target="_blank"} [Some practical Wix advice] advises that trying to do anything complicated on Wix is hell on wheels, and will lead to unending broken installs out in the field that fuck over the target systems. While Wix in theory permits arbitrarily complex and powerful installs, in practice, no one succeeds. "certain things are still coded on a case by case basis. These ad hoc solutions are implemented as 'custom actions` in Windows Installer," And custom actions that involve writing anything other than file properties, die horribly. Attempts to install Wix on Visual Studio repeatedly failed, and sometimes trashed my Visual Studio installation. After irreversibly destroying Visual Studio far too many times, attempted to install on a fresh clean virtual machine. Clean install of Visual Studio on a vm worked, loaded my project, compiled and built it almost as fast as my real machine. The program it built ran fine and passed unit test. And then Visual Studio crashed on close. Investigating the hung Visual Studio, it had freed up almost all memory, and then just stopped running. Maybe the problem is not Wix bitrot, but Visual Studio bitrot, since I did not even get as far as trying to install Wix. If the Wix installer is horribly broken, is it not likely that any install created by Wix will be horribly broken? The Wix Toolset, requires the net framework 3.5 in order to install it and use it, which is the cobbler’s children going barefoot. You want a banana, and have to install a banana tree, a monkey, and a jungle. Network Framework 3.5.1 can be installed with Control Panel/programs and programs/features. You have to install the extension after the framework in that order, or else everything breaks. Or maybe everything just breaks anyway far too often and people develop superstitions about how to avoid such cases. ## Choco Choco, Chocolatey, is the Windows Package manager system. Does not use `*.msi` as its packaging system. A chocolatey package consists of an `*.nuget`, `chocolateyInstall.ps1`, `chocolateyUninstall.ps1`, and `chocolateyBeforeModify.ps1` (the latter script is run before upgrade or uninstall, and is to reverse stuff done by is accompanying `chocolateyInstall.ps1 `) Interaction with stuff installed by `*.msi` is apt to be bad. The community distribution redirects requests to particular servers, which have to be maintained by particular people - which requires an 8GB ram, 50GB disk Windows server. I could have `nginx` in the cloud reverse proxying that to a physically local server over wireguard, which solves the certificate problem, or I could use a commercial service, which is cheap, but leaks identity all over the place and is likely to be subject to hostile interdiction and state sponsored identity theft. Getting on the `choco` list is largely automatic. Your package has to install on their standard image, which is a deliberately obsolete 2012 windows server - and your install script may have to install windows update packages. Your package is unlikely to successfully install until you have first tested it on an imitation of their test environment, which is a great deal of work and skill to set up. Human curation exists, but is normally routine and superficial. Installs, has license, done. [whole lot more checks]:https://docs.chocolatey.org/en-us/information/security#chocolatey.org-packages {target="_blank"} [whole lot more rules]:https://docs.chocolatey.org/en-us/community-repository/moderation/package-validator/rules/ {target="_blank"} Well, actually there are a [whole lot more checks], which enforce a [whole lot more rules], sixty eight rules and growing, but they are robotically checked and the outcome reported to human. If the robot OKs it, it normally goes through automatically into the community distribution. A Choco package is immutable. Can be superseded, but cannot change. Could have the program check for a Zooko signature of its package file against a list, and look for indications of broad approval, thus solving the identity problem and eating my own dogfood. Choco packages would be very handy to automatically install my build environment. ### Cmake `cmake` has a pipeline for building choco files. [wxWidgets has instructions for building with Cmake]:https://docs.wxwidgets.org/trunk/overview_cmake.html {target="_blank"} [wxWidgets has instructions for building with Cmake]. My other libraries do not, and require their own idiosyncratic build scripts, and I doubt that I can do what the authors were disinclined to do. Presumably I could fix this with `add_custom_target` and `add_custom_command`, where the custom command is bash script that just invokes the author's scripts, but I just do not understand the documentation for these commands, which documentation resupposes knowledge of the incomprehensible domain specific language. `Cmake` runs on both Windows and Linux, and is a replacement for autotools, that runs only on Linux. Going with `cmake` means you have a defined standard cross platform development environment, `vscode` which is wholly open source, and a defined standard cross platform packaging system, or rather four somewhat equivalent standard packaging systems, two for each platform. Instead of ```bash ./configure make make install ``` We have ```bat cmake .. cmake --build . cmake --install . ``` `cmake --install` installs from source, and has a pipeline (`cpack`) to generate `*.msi` through [NSIS]. Notice it does *not* have a pipeline through Wix and Wax. It also has a pipeline to Choco, and, on linux, to `*.deb` and `*.rpm`. No uninstall, which has to be hand written for your distribution. `cmake` has the huge advantage that with certain compilers, far from all of them, it integrates with the vscode ide, including a graphical debugger that runs on both windows and linux. Which otherwise you really do not have on linux. It thus provides maximum cross platform portability. On the other hand, all of my libraries rely on `.configure && make && make install` on linux, and on visual studio on Windows. In my previous encounter with `cmake`, I found mighty good reason for doing it that way. The domain specific language of `CMakeLists.txt` is arcane, unreadable, unwriteable, and subject to frequent, arbitrary, inconsistent, and illogical ad hoc change. It inexplicably does remarkably complicated things without obvious reason or purpose, which strange complexity usually does things you do not want. Glancing through their development blog, I keep seeing major breaking changes being corrected by further major breaking changes. Internals are undocumented, subject to surprising change, and likely to change further, and you have to keep editing them, without any clearly knowable boundary between what is internal stuff that you should not need to look at and edit, and what is the external language that you are supposed to use to define what `cmake` is supposed to accomplish. It is not obvious how to tell `cmake` to do a certain thing, and looking at a `CmakeLists.txt` file, not at all obvious what `cmake` is going to do. And when the next version comes out, probably going to do something different. But allegedly the domain specific language of `./configure` has grown a multitude of idiosyncrasies, making it even worse. `ccmake` is a graphical tool that will do some editing of `CMakeLists.txt` with respect for the mysterious undocumented arcane syntax of the nowhere explained or documented domain specific language. # Library Package managers Lately, however, library package managers have appeared: Conan and [vcPkg](https://blog.kitware.com/vcpkg-a-tool-to-build-open-source-libraries-on-windows/). Conan lacks wxWidgets, and has far fewer packages than [vcpkg](https://libraries.io/github/Microsoft/vcpkg). I have attempted to use package managers, and not found them very useful. It is easier to deal with each package as its own unique special case. The uniform abstraction that a package manager attempts to provide invariably leaks badly, while piling cruft on top of the library. Rather than simplifying library use, piles its own idiosyncratic complexification on top of the complexities of the library, often inducing multiplicative complexity, as one attempts to deal with the irregularities and particulars of a particular library though a package manager that is unaware of and incapable of dealing with the particularity of that particular package, and is unshakeably convinced that the library is organized in way that is different from the way it is in fact organized. # Multiprecision Arithmetic I will need multiprecision arithmetic if I represent information in a base or dictionary that is not a power of two. [MPIR]:]http://mpir.org/ {target="_blank"} [GMP]:https://gmplib.org {target="_blank"} The best libraries are [GMP] for Linux and [MPIR] for windows. These are reasonably compatible, and generally only require very trivial changes to produce a Linux version and a windows version. Boost attempts to make the changes invisible, but adds needless complexity and overhead in doing so, and obstructs control. MPIR has a Visual Studio repository on Github, and a separate Linux repository on Github. GMP builds on a lot of obscure platforms, but not really supported on Windows. For supporting Windows and Linux only, MPIR all the way is the way to go. For compatibility with little used and obscure environments, you might want to have your own custom thin layer that maps GMP integers and MPIR integers to your integers, but that can wait till we have conquered the world. My most immediate need for MPIR is the extended Euclidean algorithm for modular multiplicative inverse, which it, of course, supports, `mpz_gcdext`, greatest common divisor extended, but which is deeply hidden in the [documentation](http://www.mpir.org/mpir-3.0.0.pdf). # [wxWidgets](./libraries/building_and_using_libraries.html#instructions-for-wxwidgets){target="_blank"} # Secure compilation I am currently using Visual Studio, the most powerful, convenient, and useful code development system around. But increasingly owned by enemies of increasing wickedness and diminishing competence. Also, completely different, and not altogether compatible with, what is needed to build code on linux. I attempted to build wxWidgets using MingGW which is open source, and failed. Git is open source, and operated by good people, but its hash function is insecure, and its signing system relies on Gpg, which is designed to be part of the Web of Trust, which no longer exists and never was entirely working, and never designed for the use to which Git uses it. After we get a signing and security system, which will not be for a while, we should create a fork of Git that actually is secure. [Build environment for Git for Windows]:https://github.com/git-for-windows/build-extra{target="_blank"} [Build environment for Git for Windows] is a package that builds a package manager that installs packages that can build Git on windows. But it is a package manager, not a pile of compilers and build tools, a package manager that merely installs precompiled files from who knows where, compiled by who knows who? What we actually need is a full development environment that can build a full development environment, and you can have multiple versions of the tools on the same machine, and can select one or more all of the newly modified tools for your build environment, or build a full install package from source, including compilers, make utilities, ide, and git. When a source file for the ide or one of its components changes, the default full build action being to build the new component, and switch to it, but the release components are not overwritten, and you can switch back until you explicitly overwrite the release version by running a newly built install package or manually copy a newly built component over the release component. There should be a unit test, of course, and should unit test fail, the default action should be to switch back to the release version, and open up the source code hinted by the unit test failure. It should be a development environment that provides special case handling for development of the development environment. All this is very far indeed from what [Build environment for Git for Windows] provides, and creating it would be an enormous project, but the only way to prevent toolchain attacks is to make toolchain development readily available to everyone. # Networking ## notbit client A bitmessage client written in C. Designed to run on a linux mail server and interface bitmessage to mail. Has no UI, intended to be used with the linux mail UI. Unfortunately, setting up a linux mail server is a pain in the ass. Needs the Zooko UI. But its library contains everything you need to share data around a group of people, many of them behind NATs. Does not implement NAT penetration. Participants behind a NAT are second class unless they implement port forwarding, but participants with unstable IPs are not second class. ## Game Networking sockets [Game Networking Sockets](https://github.com/ValveSoftware/GameNetworkingSockets) A reliable udp library with congestion control which has vastly more development work done on it than any other reliable udp networking library, but which is largely used to work with Steam gaming, and Steam's closed source code. Has no end of hooks to closed source built into it, but works fine without those hooks. Written in C++. Architecture overly specific and married to Steam. Would have to be married to Tokio to have massive concurrency. But you don't need to support hundreds of clients right away. Well, perhaps I do, because in the face of DDOS attack, you need to keep a lot of long lived inactive connections around for a long time, any of which could receive a packet at any time. I need to look at the GameNetworkingSockets code and see how it listens on lots and lots of sockets. If it uses [overlapped IO], then it is golden. Get it up first, and it put inside a service later. [Overlapped IO]:server.html#the-select-problem {target="_blank"} The nearest equivalent Rust application gave up on congestion control, having programmed themselves into a blind alley. ## Tokio Tokio is a Rust framework for writing highly efficient highly scalable services. Writing networking for a service with large numbers of clients is very different between Windows and Linux, and I expect Tokio to take care of the differences. There really is not any good C or C++ environment for writing services except Wt, which is completely specialized for the case of writing a web service whose client is the browser, and which runs only on Linux. ## wxWidgets wxWidgets has basic networking capability built in and integrated with its event loop, but it is a bit basic, and is designed for a gui app, not for a server – though probably more than adequate for initial release. It only supports http, but not https and websockets. [LibSourcery](https://sourcey.com/libsourcey) is a far more powerful networking library, which supports https and websockets, and is designed to interoperate with nginx and node.js. But integrating it with wxWidgets is likely to be nontrivial. WxWidgets sample code for sockets is in %WXWIN%/samples/sockets. There is a [recently updated version on github]. Their example code supports TCP and UDP. But some people argue that the sampling is insufficiently responsive - you really need a second thread that damned well sits on the socket, rather than polling it. And that second thread cannot use wxSockets. [recently updated version on github]:https://github.com/wxWidgets/wxWidgets/tree/master/samples/sockets Programming sockets and networking in C is a mess. The [much praised guide to sockets](https://beej.us/guide/bgnet/html/single/bgnet.html) goes on for pages and pages describing a “simple” example client server. Trouble is that C, and old type Cish C++ exposes all the dangly bits. The [QT client server example](https://stackoverflow.com/questions/5773390/c-network-programming), on the other hand, is elegant, short, and self explanatory. The code project has [example code written in C++](https://www.codeproject.com/Articles/13071/Programming-Windows-TCP-Sockets-in-C-for-the-Begin), but it is still mighty intimidating compared to the QT client server example. I have yet to look at the wxWidgets client server examples – but looking for wxWidgets networking code has me worried that it is a casual afterthought, not adequately supported or adequately used. ZeroMQ is Linux, C, and Cish C++. Boost Asio is highly praised, but I tried it, and concluded its architecture is broken, trying to make simplicity and elegance where it cannot be made, resulting in leaky abstractions which leak incomprehensible complexity the moment you stray off the beaten path – I feel they have lost control of their design, and are just throwing crap at it trying to make something that cannot work, work. I similarly found the Boost time libraries failed, leaking complexity that they tried to hide, with the hiding merely adding complexity. [cpp-httplib](https://github.com/yhirose/cpp-httplib) is wonderful in its elegance, simplicity, and ease of integration. You just include a single header. Unfortunately, it is strictly http/https, and we need something that can deal with the inherently messy lower levels. [Poco](http://pocoproject.org/) does everything, and is C++, but hey, let us first see how far we can get with wxWidgets. Further, the main reason for doing https integration with the existing browser web ecosystem, whose security is fundamentally broken, due the state’s capacity to seize names, and the capacity of lots of entities to intercept ssl. It might well be easier to fork opera or embed chromium. I notice that Chromium has features supporting payment built into it, a bunch of “PaymentMethod\*\*\*\*\*Event” The best open source browser, and best privacy browser, is Opera, in that it comes from an entity less evil than Google. [Opera](https://bit.ly/2UpSTFy) needs to be configured with [a bunch of privacy add ons](https://gab.com/PatriotKracker80/posts/c3kvL3pBbE54NEFaRGVhK1ZiWCsxZz09) [HTTPS Everywhere Add-on](https://bit.ly/2ODbPeE), [uBlock](https://bit.ly/2nUJLqd), [DisconnectMe](https://bit.ly/2HXEEks), [Privacy-Badger](https://bit.ly/2K5d7R1), [AdBlock Plus](https://bit.ly/2U81ddo), [AdBlock for YouTube](https://bit.ly/2YBzqRh), two tracker blockers, and three ad blockers. It would be great if we could make our software another addon, possibly chatting by websocket to the wallet. The way it would work be to add another protocol to the browser: ro://name1.name2.name3/directory/directory/endpoint. When you connect to such an endpoint, your wallet, possibly a wallet with no global name, connects to the named wallet, and gets IP, a port, a virtual server name, a cookie unique for your wallet, and the hash of the valid ssl certificate for that name, and then the browser makes a connection to the that server, ignoring the CA system and the DNS system. The name could be a DNS name and the certificate a CA certificate, in which case the connection looks to the server like any other, except for the cookie which enables it to send messages, typically a payment request, to the wallet. # zk-snarks The most advanced, and most useful for blockchains, zk-snark technology is polygon, which claims to have finally found the holy grail: the actually useful generation and verification of proofs of verification. So that Bob can not only verify that Ann's information is what she says it is without knowing that information, Carol can verify that Bob verified, and Dave can verify that Carol verified it. Which gives us scaling. Bob can verify that several people's transactions are valid, Carol can verify several Bobs, and Dave can verify several Carols. I have seen no end of claims that zk-snark system can do so and so, when, though it can in principle do so and so, actually getting it to do so and so is very hard and they have not quite managed to get it quite working, or they have actually gotten it to work but there are a bunch of complicated gotchas that make it impractical, or unwise, or not very useful to do so and so. But I have also seen a great deal of real progress in solving these problems, albeit the progress tends to be overpromised and underdelivered, but the for all that, the progress is real and substantial. [Aurora]:https://eprint.iacr.org/2018/828.pdf {target="_blank"} Supposedly there is a language, R1CS, such that you can express a program that gives a true false answer, such that [Aurora] can execute the program and generate a prover and a verifier. [starkware]:https://iacr.org/submit/files/slides/2021/rwc/rwc2021/1005/slides.pdf {target="_blank"} According to [starkware], they have the fastest proving time, but their proofs are rather large, 138KiB, Groth16 Snarks have the most compact proofs. Not actually seeing it as a useful library yet that I could actually use, but more like a proof of principle that someone could build such a library. To be actually useful, a zk-snark system needs to be a compiler, that compiles a program written in what Starkware calls R1CS, and other people are calling script, and generates two programs, a prover and a\ verifier. The prover operates on two blobs, the public blob and private blob, and produces a boolean result, true or false, pass or fail, and a proof that it\ did so. The proof is approximately constant size, regardless of how much computation is required and regardless of how large the private blob was, but takes a very long time. The verifier operates on the public blob and the proof, takes a short and approximately constant time to do so, regardless of how big the computation was, and regardless of how big the private data was and determines, with 2^(126) likelihood of error, what result the prover got. But at present I get the impression that neither script nor R1CS have any real existence, though I have seen a script language that operates on a stack, and, though it has no variables, can dupe any item on the stack to the top of the stack. It seems to have only been ever used to generate one prover and one verifier, because actually creating the prover and verifier still required some coding by hand. Also lacked certain control structures. At present, people seem to be writing the prover and the verifier by hand, a very difficult operation with a very high likelihood of bugs. The prover and the verifier do very simple tasks like proving the encoded inputs to a transaction are greater than or equal to the encoded outputs and that no numeric underflow or overflow occurred. Another problem is that we would really like the public data to be the root hash of a merkle tree, and no one seems to have a script language that contains a useful hash function Stackware is built out of hash functions, but last time I looked, you could not call a hash function from R1CS. We need a script language that can not merely add and subtract, but can also do hashes and elliptic point operations. zk-stark systems are built out of hashes and elliptic point operations, but it seems to be uphill trying to generate proofs that prove something about the results of hashes and elliptic point operations, making very difficult to produce a proof that a pile of proofs in the pre-image of a merkle tree have been verified. I suspect that a prover might take a very very long time to produce such a proof. The proofs are succinct, in that you can prove something about a gigantic pile of data and the size of the proof and the time taken to verify scarcely grows - about 128 KiB, for the smallest that anyone would care about, to utterly gigantic proofs. But proof generation is not all that fast, and grows with the matter to be proven, so to be useful for utterly gigantic proofs, you would need to be able to distribute proof generation over an enormous multitude of untrusting shards. Which you can obviously do by proving a verification. Not sure how long it takes to produce a proof that a large number of proofs were verified. What you want is to be able to prove that a final hash is the root of of an enormous merkle tree, some generalization of a merkle-patricia tree, representing an immutable append only data structure consisting of a sequence of piles of transactions, and the state generated by these transactions, represents a valid branch of a chain of signatures, that the final state is correctly derived by applying the batch of transactions to the previous state. And then you want to do this for states so enormous, and piles of transactions so enormous, that no one person has all of them. And then you still have the problem of resolving forks. You would like to have a blockchain of blockchains of blockchains, such that your state, and your transactions, are divided into a product of substates, with consensus on each substate advancing a bit ahead of the consensus on the combination of several substates, so that transactions within a substate finalize fast, but transactions between substates take longer. (because the number of forks of the product state is the product of the number of forks of each substate) Each of the substates very quickly comes up with a proof that a transaction within a substate is valid and quickly comes up with consensus as to which fork everyone is on, but the proof for a transaction between substates is finalized quickly in the paying substate, and quickly affects the paying substate, but the transaction does not get included in the state that is a product of the receiving and paying substate for a while, does not get proven valid in the product substate for a while, and does not get included in the receiving substate till a bit after than it is included in the product substate, whereupon it is in due course quickly proven to be a valid addition of value to the receiving substate. So that the consensus problem remains manageable, we need insulation and delay between the states, so that the product state has its own pile of state, representing the delay between a transaction affecting a the payer factor state, and the transaction affecting the payee factor state. A transaction has no immediate affect. The payer mutable substate changes in a way reflecting the transaction block at the next block boundary. And that change then has effect on product mutable state at a subsequent product state block boundary, changing the stake possessed by the substate. Which then has effect on the payee mutable substate at its next block boundary when the payee substate links back to the previous product state. # wxSqlite3 wxSqlite integrates a third free open source encryption library that appears to use libSodium encryption algorithms into Sqlite to provide encrypted databases, and integrates sqlite3 databases into one of the wxWidgets tools, but not, however, the one that I actually want, wGrid. More layers lead to more attack surface, so it would be better to use wxSqlite as a model for the integration, rather than using it directly, and then use a fork of the third party library, rather than using it directly. # Safe maths [Safeint]:https://github.com/dcleblanc/SafeInt {target="_blank"} We could implement transaction outputs and inputs as a fixed amount of fungible tokens, limited to $2^{64}-1$ tokens, using [Safeint] That will be future proof for a long time, but not forever. Indeed, anything that does not use Zksnarks is not future proof for the indefinite future. Or we could implement decimal floating point with unlimited exponents and mantissa implemented on top of [MPIR] Or we could go ahead with the canonical representation being unlimited decimal exponent and unlimited mantissa, but the wallet initially only generates, and only can handle, transactions that can be represented by[Safeint], and always converts the mantissa plus decimal exponent to and from a safeint. if we rely on safeint, and our smallest unit is the microrho, that is room for eighteen trillion rho. We can start actually using the unlimited precision of the exponent and the mantissa in times to come - not urgent, merely architect it into the canonical format. From the point of view of the end user, this will merely be an upgrade that allows nanorho, picorho, femptorho, attorho, zeptorho, yoctorho, and allows a decimal point in yoctorho quantities. And then we go to a new unit, the jim, with one thousand yottajim equals one yoctorho, a billion yoctojim equals one attorho, a trillion exajim equals one attorho. To go all the way around to two byte exponents, for testing purposes, will need some additional new units after the jim. (And we should impose a minimum unit size of $10^{-195}$ rho or $10{-6} rho, thereby ensuring that transaction size is bounded while allowing compatibility for future expansion.) Except in test and development code, any attempt to form a transaction involving quantities with exponents less than $1000^{-2}$ will cause a gracefully handled exception, and in all code any attempt to display or perform calculations on transaction inputs and outputs for which no display units exist will cause an ungracefully handled exception. In the first release configuration parameters, the lowest allowed exponent will be $1000^{-2}$, corresponding to microrho, and the highest allowed exponent $1000^4$, corresponding to terarho, and machines will be programmed to vote "incapable" and "no" on any proposal to change those parameters. However they will correctly handle transactions beyond those limits provided that when quantities are expressed in the smallest unit of any of the inputs and outputs, the sum of all the inputs and of all the outputs remains below $2^{64}$. To ensure that all releases are future compatible, the blockchain should have some exajim transactions, and unspent transaction outputs but the peers should refuse to form any more of them. The documentation will say that arbitrarily small and large new transaction outputs used to be allowed, but are currently not allowed, to reduce the user interface attack surface that needs to be security checked and to limit blockchain bloat, and since there is unlikely to be demand for this, this will probably not be fixed for a very long time. Or perhaps it would be less work to support humungous transactions from the beginning, subject to some mighty large arbitrary limit to prevent denial of service attack, and eventually implementing native integer handling of normal sized transactions as an optimization, for transactions where all quantities fit within machine sized words, and rescaled intermediate outputs will be less than $64 - \lceil log_2($number of inputs and outputs$) \rceil$ bits. Which leads me to digress how we are going to handle protocol updates: ## handling protocol updates 1. Distribute software capable of handling the update. 1. A proposed protocol update transaction is placed on the blockchain. 1. Peers indicate capability to handle the protocol update. Or ignore it, or indicate that they cannot. If a significant number of peers indicate capability, peers that lack capability push their owners for an update. 1. A proposal to start emitting data that can only handled by more recent peers is placed on the blockchain. 1. If a significant number of peers vote yes, older peers push more vigorously for an update. 1. If a substantial supermajority votes yes by a date specified in the proposal, then they start emitting data in the new format on a date shortly afterwards. If no supermajority by the due date, the proposal is dead. # [Zlib compression libraries.](./libraries/zlib.html) Built it, easy to use, easy to build, easy to link to. Useful for large amounts of text, provides, but does not use, CRC32 [Cap\'n Proto](./libraries/capnproto.html) [Crypto libraries](./libraries/crypto_library.html) [Memory Safety](./libraries/memory_safety.html). [C++ Automatic Memory Management](./libraries/cpp_automatic_memory_management.html) [C++ Multithreading](./libraries/cpp_multithreading.html) [Catch testing library](https://github.com/catchorg/Catch2) [Boost](https://github.com/boostorg/boost) ------------------------------------------------------------------------ ## Boost My experience with Boost is that it is no damned good: They have an over elaborate pile of stuff on top of the underlying abstractions, which pile has high runtime cost, and specializes the underlying stuff in ways that only work with boost example programs and are not easily generalized to do what one actually wishes done. Their abstractions leak. [Boost high precision arithmetic `gmp_int`]:https://gmplib.org/ [Boost high precision arithmetic `gmp_int`] A messy pile built on top of GMP. Its primary benefit is that it makes `gmp` look like `mpir` Easier to use [MPIR] directly. The major benefit of boost `gmp` is that it runs on some machines and operating systems that `mpir` does not, and is for the most part source code compatible with `mpir`. A major difference is that boost `gmp` uses long integers, which are on sixty four bit windows `int32_t`, where `mpir` uses `mpir_ui` and `mpir_si`, which are on sixty four bit windows `uint64_t` and `int64_t`. This is apt to induce no end of major porting issues between operating systems. Boost `gmp` code running on windows is apt to produce radically different results to the same boost `gmp` code running on linux. Long `int` is just not portable, and should never be used. This kind of issue is absolutely typical of boost. In addition to the portability issue, it is also a typical example of boost abstractions denying you access to the full capability of the thing being abstracted away. It is silly to have a thirty two bit interface between sixty four bit hardware and unlimited arithmetic precision software. ------------------------------------------------------------------------ ## Database The blockchain is a massively distributed database built on top of a pile of single machine, single disk, databases communicating over the network. If you want a single machine, single disk, database, go with SQLite, which in WAL mode implements synch interaction on top of hidden asynch. [SQLite](https://www.Sqlite.org/src/doc/trunk/README.md) have their own way of doing things, that does not play nice with Github. The efficient and simple way to handle interaction with the network is via callbacks rather than multithreading, but you usually need to handle databases, and under the hood, all databases are multithreaded and blocking. If they implement callbacks, it is usually on top of a multithreaded layer, and the abstraction is apt to leak, apt to result in unexpected blocking on a supposedly asynchronous callback. SQLite recommends at most one thread that writes to the database, and preferably only one thread that interacts with the database. ## The Invisible Internet Project (I2P) [Comes](https://geti2p.net/en/) with an I2P webserver, and the full api for streaming stuff. These appear as local ports on your system. They are not tcp ports, but higher level protocols, *and* UDP. (Sort of UDP - obviously you have to create a durable tunnel, and one end is the server, the other the client.) Inconveniently, written in java. ## Internet Protocol [QUIC] UDP with flow control and reliability. Intimately married to http/2, https/2, and google chrome. Cannot call as library, have to analyze code, extract their ideas, and rewrite. And, looking at their code, I think they have written their way into a blind alley. But QUIC is http/2, and there is a gigantic ecosystem supporting http/2. We really have no alternative but to somehow interface to that ecosystem. [QUIC]: https://github.com/private-octopus/picoquic [QUIC] is UDP with flow control, reliability, and SSL/TLS encryption, but no DDoS resistance, and total insecurity against CA attack.) ## Boost Asynch Boost implements event oriented multithreading in IO service, but don’t like it because it fails to interface with Microsoft’s implementation of asynch internet protocol, WSAAsync, and WSAEvent. Also because brittle, incomprehensible, and their example programs do not easily generalize to anything other than that particular example. To the extent that you need to interact with a database, you need to process connections from clients in many concurrent threads. Connection handlers are run in thread, that called `io_service::run()`. You can create a pool of threads processing connection handlers (and waiting for finalizing database connection), by running `io_service::run()` from multiple threads. See Boost.Asio docs. ## Asynch Database access MySQL 5.7 supports [X Plugin / X Protocol, which allows asynchronous query execution and NoSQL But X devapi was created to support node.js and stuff. The basic idea is that you send text messages to mysql on a certain port, and asynchronously get text messages back, in google protobuffs, in php, JavaScript, or sql. No one has bothered to create a C++ wrapper for this, it being primarily designed for php or node.js](https://dev.mysql.com/doc/refman/5.7/en/document-store-setting-up.html) SQLite nominally has synchronous access, and the use of one read/write thread, many read threads is recommended. But under the hood, if you enable WAL mode, access is asynchronous. The nominal synchrony sometimes leaks into the underlying asynchrony. By default, each `INSERT` is its own transaction, and transactions are excruciatingly slow. Wal normal mode fixes this. All writes are writes to the writeahead file, which gets cleaned up later. The authors of SQLite recommend against multithreading writes, but we do not want the network waiting on the disk, nor the disk waiting on the network, therefore, one thread with asynch for the network, one purely synchronous thread for the SQLite database, and a few number crunching threads for encryption, decryption, and hashing. This implies shared nothing message passing between threads. ------------------------------------------------------------------------ [Facebook Folly library]provides many tools, with such documentation as exists amounting to “read the f\*\*\*\*\*g header files”. They are reputed to have the highest efficiency queuing for interthread communication, and it is plausible that they do, because facebook views efficiency as critical. Their [queuing header file] (https://github.com/facebook/folly/blob/master/folly/MPMCQueue.h) gives us `MPMCQueue`. [Facebook Folly library]:https://github.com/facebook/folly/blob/master/folly/ On the other hand, boost gives us a lockless interthread queue, which should be very efficient. Assuming each thread is an event handler, rather than pseudo synchronous, we queue up events in the boost queue, and handle all unhandled exceptions from the event handler before getting the next item from the queue. We keep enough threads going that we do not mind threads blocking sometimes. The queue owns objects not currently being handled by a particular thread. Objects are allocated in a particular thread, and freed in a particular thread, which process very likely blocks briefly. Graphic events are passed to the master thread by the wxWindows event code, but we use our own mutltithreaded event code to handle everything else. Posting an event to the gui code will block briefly. I was looking at boost’s queues and lockless mechanisms from the point of view of implementing my own thread pool, but this is kind of stupid, since boost already has a thread pool mechanism written to handle the asynch IO problem. Thread pools are likely overkill. Node.js does not need them, because its single thread does memory to memory operations. Boost provides us with an [`io_service` and `boost::thread` group], used to give effect to asynchronous IO with a thread pool. `io_service` was specifically written to perform io, but can be used for any thread pool activity whatsoever. You can “post” tasks to the io_service, which will get executed by one of the threads in the pool. Each such task has to be a functor. [`io_service` and `boost::thread` group]:http://thisthread.blogspot.com/2011/04/multithreading-with-asio.html Since supposedly nonblocking operations always leak and block, all we can do is try to have blocking minimal. For example nonblocking database operations always block. Thus our threadpool needs to be many times larger than our set of hardware threads, because we will always wind up doing blocking operations. The C++11 multithreading model assumes you want to do some task in parallel, for example you are multiplying two enormous matrices, so you spawn a bunch of threads, then you wait for them all to complete using `join`, or all to deliver their payload using futures and promises. This does not seem all that useful, since the major practical issue is that you want your system to continue to be responsive while it is waiting for some external hardware to reply. When you are dealing with external events, rather than grinding a matrix in parallel, event oriented architecture, rather than futures, promises, and joins is what you need. Futures, promises, and joins are useful in the rather artificial case that responding to an remote procedure call requires you to make two or more remote procedure calls, and wait for them to complete, so that you then have the data to respond to a remote procedure call. Futures, promises, and joins are useful on a server that launches one thread per client, which is often a sensible way to do things, but does not fit that well to the request response pattern, where you don’t have a great deal of client state hanging around, and you may well have ten thousand clients If you can be pretty sure you are only going to have a reasonably small number of clients at any one time, or and significant interaction between clients, one thread per client may well make a lot of sense. I was planning to use boost asynch, but upon reading the boost user threads, sounds fragile, a great pile of complicated unintelligible code that does only one thing, and if you attempt to do something slightly different, everything falls apart, and you have to understand a lot of arcane details, and rewrite them. [Nanomsg](http://nanomsg.org/)is a socket library, that provides a layer on top of everything that makes everything look like sockets, and provides sockets specialized to various communication patterns, avoiding the roll your own problem. In the zeroMQ thread, people complained that [a simple hello world TCP-IP program tended to be disturbingly large and complex] Looks to me that [Nanomsg] wraps a lot of that complexity. [a simple hello world TCP-IP program tended to be disturbingly large and complex]:http://250bpm.com/blog # Sockets A simple hello world TCP-IP program tends to be disturbingly large and complex, and windows TCP-IP is significantly different from posix TCP-IP. Waiting on network events is deadly, because they can take arbitrarily large time, but multithreading always bites. People who succeed tend to go with single thread asynch, similar to, [or part of, the window event handling loop]. [or part of, the window event handling loop]:https://www.codeproject.com/Articles/13071/Programming-Windows-TCP-Sockets-in-C-for-the-Begin Asynch code should take the form of calling a routine that returns immediately, but passing it a lambda callback, which gets executed in the most recently used thread. Interthread communication bites – you don’t want several threads accessing one object, as synch will slow you down, so if you multithread, better to have a specialist thread for any one object, with lockless queues passing data between threads. One thread for all writes to SQLite, one thread for waiting on select. Boost Asynch supposedly makes sockets all look alike, but I am frightened of their work guard stuff – looks to me fragile and incomprehensible. Looks to me that no one understands boost asynch work guard, not even the man who wrote it. And they should not be using boost bind, which has been obsolete since lambdas have been available, indicating bitrot. Because work guard is incomprehensible and subject to change, will just keep the boost io object busy with a polling timer. And I am having trouble finding boost asynch documented as a sockets library. Maybe I am just looking in the wrong place. [A nice clean tutorial depicting strictly synchronous tcp.](https://www.binarytides.com/winsock-socket-programming-tutorial/) [Libpcap and Win10PCap](https://en.wikipedia.org/wiki/Pcap#Wrapper_libraries_for_libpcap) provide very low level, OS independent, access to packets, OS independent because they are below the OS, rather than above it. [Example code for visual studio.](https://www.csie.nuk.edu.tw/~wuch/course/csc521/lab/ex1-winpcap/) [Simple sequential procedural socket programming for windows sockets.](https://www.binarytides.com/winsock-socket-programming-tutorial/) If I program from the base upwards, the bottom most level would be a single thread sitting on a select statement. Whenever the select fired, would execute a corresponding functor transfering data between userspace and system space. One thread, and only one thread, responsible for timer events and transferring network data between userspace and systemspace. If further work required in userspace that could take significant time (disk operations, database operations, cryptographic operations) that functor under that thread would stuff another functor into a waitless stack, and a bunch of threads would be waiting for that waitless stack to be signaled, and one of those other threads would execute that functor. The reason we have a single userpace thread handling the select and transfers between userpace and systemspace is that that is a very fast and very common operation, and we don’t want to have unnecessary thread switches, wherein one thread does something, then immediately afterwards another thread does almost the same thing. All quickie tasks should be handled sequentially by one thread that works a state machine of functors. The way to do asynch is to wrap sockets in classes that reflect the intended use and function of the socket. Call each instance of such a class a connection. Each connection has its own state machine state and its own **message dispatcher, event handler, event pump, message pump**. A single thread calls select and poll, and drives all connection instances in all transfers of data between userspace and systemspace. Connections also have access to a thread pool for doing operations (such as file, database and cryptography, that may involve waits. The hello world program for this system is to create a derived server class that does a trivial transformation on input, and has a path in server name space, and a client class that sends a trivial input, and displays the result. Microsoft WSAAsync\[Socketprocedure\] is a family of socket procedures designed to operate with, and be driven by, the Window ui system, wherein sockets are linked to windows, and driven by the windows message loop. Could benefit considerably by being wrapped in connection classes. I am guessing that wxWidgets has a similar system for driving sockets, wherein a wxSocket is plugged in to the wxWidget message loop. On windows, wxWidget wraps WSASelect, which is the behavior we need. Microsoft has written the asynch sockets you need, and wxWidgets has wrapped them in an OS independent fashion. WSAAsyncSelect WSAEventSelect select Using wxSockets commits us to having a single thread managing everything. To get around the power limit inherent in that, have multiple peers under multiple names accessing the same database, and have a temporary and permanent redirect facility – so that if you access `peername,` your connection, and possibly your link, get rewritten to `p2.peername` by peers trying to balance load. Microsoft tells us: > receiving, applications use the WSARecv or WSARecvFrom functions to supply buffers into which data is to be received. If one or more buffers are posted prior to the time when data has been received by the network, that data could be placed in the user’s buffers immediately as it arrives. Thus, it can avoid the copy operation that would otherwise occur at the time the recv or recvfrom function is invoked. Moral is, we should use the sockets that wrap WSA. # Tcl Tcl is a really great language, and I wish it would become the language of my new web, as JavaScript is the language of the existing web. When I search for Tcl, I am apt to find a long out of date repository preserved for historical reasons, but there is an active repository obscured by the existence of the out of date repository. Javascript is a great language, and has a vast ecosystem of tools, but it is controlled from top to bottom by our enemies, and using it is inherently insecure. It consists of a string (which is implemented under the hood as a copy on write rope, with some substrings of the rope actually being run time typed C++ types that can be serialized and deserialized to strings) and a name table, one name table per interpreter, and at least one interpreter per thread. The entries in the name table can be strings, C++ functions, or run time typed C++ types, which may or may not be serializable or deserializable, but conceptually, it is all one big string, and the name table is used to find C and C++ functions which interpret the string following the command. Execution consists of executing commands found in the string, which transform it into a new string, which in turn gets transformed into a new string, until it gets transformed into the final result. All code is metacode. If elements of the string need to be deserialized to and from a C++ run time type, (because the command does not expect that run time type) but cannot be, because there is no deserialization for that run time type, you get a run time error, but most of the time you get, under the hood, C++ code executing C++ types – it is only conceptually a string being continually transformed into another string. The default integer is infinite precision, because integers are conceptually arbitrary length strings of numbers. To sandbox third party code, including third party gui code, just restrict the nametable to have no dangerous commands, and to be unable to load c++ modules that could provide dangerous commands. It is faster to bring up a UI in Tcl than in C. We get, for free, OS independence. Tcl used to be the best level language for attaching C programs to, and for testing C programs, or it would be if SWIG actually worked. The various C components of Tcl provide an OS independent layer on top of both Linux and Windows, and it has the best multithread and asynch system. It is also a metaprogramming language. Every Tcl program is a metaprogram – you always write code that writes code. The Gui is necessarily implemented as asynch, something like the JavaScript dom in html, but with explicit calls to the event/idle loop. Multithreading is implemented as multiple interpreters, at least one interpreter per thread, sending messages to each other. # Time After spending far too much time on this issue, which is has sucked in far too many engineers and far too much thought, and generated far too many libraries, I found the solution was c++11 Chrono: For short durations, we use the steady time in milliseconds, where each machine has its own epoch, and no two machines have exactly the same milliseconds. For longer durations, we use the system time in seconds, where all machines are expected to be within a couple of seconds of each other. For the human readable system time in seconds to be displayed on a particular machine, we use the ISO format 2012‑01‑14_15:39:34+10:00 (timezone with 10 hour offset equivalent to Greenwich time 2012‑01‑14_05:39:34+00:00) [For long durations, we use signed system time in seconds, for short durations unsigned steady time in milliseconds.](./libraries/rotime.cpp) Windows and Unix both use time in seconds, but accessed and manipulated in incompatible ways. Boost has numerous different and not altogether compatible time libraries, all of them overly clever and all of them overly complicated. wxWidgets has OS independent time based on milliseconds past the epoch which however fails to compress under Cap\'n Proto. I was favourably impressed by the approach to time taken in tcp packets, that the time had to be approximately linear, and in milliseconds or larger, but they were entirely relaxed about the two ends of a tcp connection using different clocks with different, and variable, speeds. It turns out you can go a mighty long way without a global time, and to the extent that you do need a global time, should be equivalent to that used in email, which magically hides the leap seconds issue. # UTF‑8 strings Are supported by the wxWidgets wxString, which provide support to and from wide character variants and locale variants. (We don't want locale variants, they are obsolete. The whole world is switching to UTF, but our software and operating environments lag) `wString::ToUTF8()` and `wString::FromUTF8()` do what you would expect. On visual studio, need to set your source files to have bom, so that Visual Studio knows that they are UTF‑8, need to set the compiler environment in Visual Studio to UTF‑8 with `/Zc:__cplusplus /utf-8 %(AdditionalOptions)` And you need to set the run time environment of the program to UTF‑8 with a manifest. You will need to place all UTF‑8 string literals and string constants in a resource file, which you will use for translated versions. If you fail to set the compilation and run time environment to UTF‑8 then for extra confusion, your debugger and compiler will *look* as if they are handling UTF‑8 characters correctly as single byte characters, while at least wxString alerts you that something bad is happening by run time translating to the null string. Automatic string conversion in wxWidgets is *not* UTF‑8, and if you have any unusual symbols in your string, you get a run time error and the empty string. So wxString automagic conversions will rape you in the ass at runtime, and for double the confusion, your correctly translated UTF‑8 strings will look like errors. Hence the need to make sure that the whole environment from source code to run time execution is consistently UTF‑8, which has to be separately ensured in three separate place. When wxWidgets is compiled using `#define wxUSE_UNICODE_UTF8 1`, it provides UTF‑8 iterators and caches a character index, so that accessing a character by index near a recently used character is fast. The usual iterators `wx.begin()`, `wx.end()`, const and reverse iterators are available. I assume something bad happens if you advance a reverse iterator after writing to it. wxWidgets compiled with `#define wxUSE_UNICODE_UTF8 1` is the way of the future, but not the way of the present. Still a work in progress Does not build under Windows. Windows now provide UTF8 entries to all its system functions, which should make it easy. wxWidgets provides `wxRegEx` which, because wxWidgets provides index by entity, should just work. Eventually. Maybe the next release. # [UTF8-CPP](http://utfcpp.sourceforge.net/ "UTF-8 with C++ in a Portable Way") A powerful library for handling UTF‑8. This somewhat duplicates the facilities provided by wxWidgets with `wxUSE_UNICODE_UTF8==1` For most purposes, wxString should suffice, when it actually works with UTF8. Which it does not yet on windows. We shall see. wxWidgets recommends not using wxString except to communicate with wxWidgets, and not using it as general UTF‑8 system. Which is certainly the current state of play with wxWidgets. For regex to work correctly, probably need to do it on wxString's native UTF‑16 (windows) or UTF‑32 (unix), but it supposedly works on `UTF8`, assuming you can successfully compile it, which you cannot. # Cap\'n Proto [Designed for a download from github and run cmake install.](https://capnproto.org/install.html) As all software should be. But for mere serialization to of data to a form invariant between machine architectures and different compilers and different compilers on the same machine, overkill for our purposes. Too much capability. # Awesome C++ [Awesome C++] A curated list of awesome C/C++ frameworks, libraries, resources, and shiny things [Awesome C++]:https://cpp.libhunt.com "A curated list of awesome C/C++ frameworks, libraries, resources, and shiny things" {target="_blank"} I encountered this when looking at the Wt C++ Web framework, which seems to be mighty cool except I don't think I have any use for a web framework. But [Awesome C++] has a very pile of things that I might use. Wt has the interesting design principle that every open web page maps to a windows class, every widget on the web page, maps to a windows class, every row in the sql table maps to a windows class. Cool design. # Opaque password protocol [Opaque] is PAKE done right. [Opaque]:https://blog.cryptographyengineering.com/2018/10/19/lets-talk-about-pake/ "Let’s talk about PAKE" {target="_blank"} Server stores a per user salt, the users public key, and the user's secret key encrypted with a secret that only the user ever learns. Secret is generated by the user from the salt and his password by interaction with the server without the the user learning the salt, nor the hash of the salt, nor the server the password or the hash of the password. User then strengthens the secret generated from salt and password applying a large work factor to it, and decrypts the private key with it. User and server then proceed with standard public key cryptography. If the server is evil, or the bad guys seize the server, everything is still encrypted and they have to run, not a hundred million trial passwords against all users, but a hundred million passwords against *each* user. And user can make the process of trying a password far more costly and slow than just generating a hash. Opaque zero knowledge is designed to be as unfriendly as possible to big organizations harvesting data on an industrial scale. The essential design principle of this password protocol is that breaking a hundred million passwords by password guessing should be a hundred million times as costly as breaking one password by password guessing. The protocol is primarily designed to obstruct the NSA's mass harvesting. It has the enormous advantage that if you have one strong password which you use for many accounts, one evil server cannot easily attack your accounts on other servers. To do that, it has to try every password - which runs into your password strengthening.