rust-overlay.nix

# Define component resolution and utility functions.
self: super:

let
  inherit (builtins) compareVersions fromTOML match readFile tryEval;

  inherit (self.lib)
    any attrNames attrValues concatMapStrings concatStringsSep elem elemAt filter flatten foldl'
    hasPrefix head intersectLists isString length listToAttrs makeLibraryPath makeOverridable mapAttrs
    mapAttrsToList optional optionalAttrs optionalString remove replaceStrings substring subtractLists trace unique;

  # Remove keys from attrsets whose value is null.
  removeNulls = set:
    removeAttrs set
      (filter (name: set.${name} == null)
        (attrNames set));

  # FIXME: https://github.com/NixOS/nixpkgs/pull/146274
  toRustTarget = platform:
    if platform.isWasi then
      "${platform.parsed.cpu.name}-wasi"
    else
      self.rust.toRustTarget platform;

  # The platform where `rustc` is running.
  rustHostPlatform = toRustTarget self.stdenv.hostPlatform;
  # The platform of binary which `rustc` produces.
  rustTargetPlatform = toRustTarget self.stdenv.targetPlatform;

  mkComponentSet = self.callPackage ./mk-component-set.nix {
    inherit toRustTarget removeNulls;
  };

  mkAggregated = self.callPackage ./mk-aggregated.nix {};

  # Manifest selector.
  selectManifest = { channel, date ? null }: let
    inherit (self.rust-bin) manifests;

    assertWith = cond: msg: body: if cond then body else throw msg;

    # https://rust-lang.github.io/rustup/concepts/toolchains.html#toolchain-specification
    # <channel> = stable|beta|nightly|<major.minor>|<major.minor.patch>

    asVersion = match "[0-9]+\\.[0-9]+(\\.[0-9]+)?" channel;
    asNightlyDate = let m = match "nightly-([0-9]+-[0-9]+-[0-9]+)" channel; in
      if m == null then null else elemAt m 0;
    asBetaDate = let m = match "beta-([0-9]+-[0-9]+-[0-9]+)" channel; in
      if m == null then null else elemAt m 0;

    maxWith = zero: f: foldl' (lhs: rhs: if lhs == zero || f lhs rhs < 0 then rhs else lhs) zero;

    latestStableWithMajorMinor =
      maxWith "" compareVersions
        (filter (hasPrefix (channel + "."))
          (attrNames manifests.stable));

  in
    # "stable"
    if channel == "stable" then
      assertWith (date == null) "Stable version with specific date is not supported"
        manifests.stable.latest
    # "nightly"
    else if channel == "nightly" then
      manifests.nightly.${if date != null then date else "latest"} or (throw "Nightly ${date} is not available")
    # "beta"
    else if channel == "beta" then
      manifests.beta.${if date != null then date else "latest"} or (throw "Beta ${date} is not available")
    # "1.49.0" or "1.49"
    else if asVersion != null then
      assertWith (date == null) "Stable version with specific date is not supported" (
        # "1.49"
        if asVersion == [ null ] then
          manifests.stable.${latestStableWithMajorMinor} or (throw "No stable ${channel}.* is available")
        # "1.49.0"
        else
          manifests.stable.${channel} or (throw "Stable ${channel} is not available"))
    # "beta-2021-01-01"
    else if asBetaDate != null then
      assertWith (date == null) "Cannot specify date in both `channel` and `date`"
        manifests.beta.${asBetaDate} or (throw "Beta ${asBetaDate} is not available")
    # "nightly-2021-01-01"
    else if asNightlyDate != null then
      assertWith (date == null) "Cannot specify date in both `channel` and `date`"
        manifests.nightly.${asNightlyDate} or (throw "Nightly ${asNightlyDate} is not available")
    # Otherwise
    else throw "Unknown channel: ${channel}";

  # Select a toolchain and aggregate components by rustup's `rust-toolchain` file format.
  # See: https://rust-lang.github.io/rustup/concepts/profiles.html
  # Or see source: https://github.com/rust-lang/rustup/blob/84974df1387812269c7b29fa5f3bb1c6480a6500/doc/src/overrides.md#the-toolchain-file
  fromRustupToolchain = { path ? null, channel ? null, profile ? null, components ? [], targets ? [] }:
    if path != null then throw "`path` is not supported, please directly add it to your PATH instead"
    else if channel == null then throw "`channel` is required"
    else
      let
        toolchain = toolchainFromManifest (selectManifest { inherit channel; });
        profile' = if profile == null then "default" else profile;
        pkg =
          if toolchain._profiles != {} then
            toolchain._profiles.${profile'} or (throw ''
              Rust ${toolchain._version} doesn't have profile `${profile'}`.
              Available profiles are: ${concatStringsSep ", " (attrNames toolchain._profiles)}
            '')
          # Fallback to package `rust` when profiles are not supported and not specified.
          else if profile == null then
            toolchain.rust
          else
            throw "Cannot select profile `${profile'}` since rust ${toolchain._version} is too early to support profiles";
      in pkg.override {
        extensions = components;
        inherit targets;
      };

  # Same as `fromRustupToolchain` but read from a `rust-toolchain` file (legacy one-line string or in TOML).
  fromRustupToolchainFile = path: let
    content = readFile path;
    legacy = match "([^\r\n]+)\r?\n?" content;
  in if legacy != null
    then fromRustupToolchain { channel = head legacy; }
    else fromRustupToolchain (fromTOML content).toolchain;

  mkComponentSrc = { url, sha256 }:
    let
      url' = replaceStrings [" "] ["%20"] url; # This is required or download will fail.
      # Filter names like `llvm-tools-1.34.2 (6c2484dc3 2019-05-13)-aarch64-unknown-linux-gnu.tar.xz`
      matchParenPart = match ".*/([^ /]*) [(][^)]*[)](.*)" url;
      name = if matchParenPart == null then "" else (elemAt matchParenPart 0) + (elemAt matchParenPart 1);
    in
      self.fetchurl { inherit name sha256; url = url'; };

  # Resolve final components to install from mozilla-overlay style `extensions`, `targets` and `targetExtensions`.
  #
  # `componentSet` has a layout of `componentSet.<name>.<rust-target> : Derivation`.
  # `targetComponentsList` is a list of all component names for target platforms.
  # `name` is only used for error message.
  #
  # Returns a list of component derivations, or throw if failed.
  resolveComponents =
    { name
    , componentSet
    , allComponentSet
    , allPlatformSet
    , targetComponentsList
    , profileComponents
    , extensions
    , targets
    , targetExtensions
    }:
    let
      # Components for target platform like `rust-std`.
      collectTargetComponents = allowMissing: name:
        let
          targetSelected = flatten (map (tgt: componentSet.${tgt}.${name} or []) targets);
        in if !allowMissing -> targetSelected != [] then
          targetSelected
        else
          "Component `${name}` doesn't support any of targets: ${concatStringsSep ", " targets}";

      collectComponents = allowMissing: name:
        if elem name targetComponentsList then
          collectTargetComponents allowMissing name
        else
          # Components for host platform like `rustc`.
          componentSet.${rustHostPlatform}.${name} or (
            if allowMissing then []
            else "Host component `${name}` doesn't support `${rustHostPlatform}`");

      # Profile components can be skipped silently when missing.
      # Eg. `rust-mingw` on non-Windows platforms, or `rust-docs` on non-tier1 platforms.
      result =
        flatten (map (collectComponents true) profileComponents) ++
        flatten (map (collectComponents false) extensions) ++
        flatten (map (collectTargetComponents false) targetExtensions);

      isTargetUnused = target:
        !any (name: componentSet ? ${target}.${name})
          # FIXME: Get rid of the legacy component `rust`.
          (filter (name: name == "rust" || elem name targetComponentsList)
            (profileComponents ++ extensions)
          ++ targetExtensions);

      # Fail-fast for typo in `targets`, `extensions`, `targetExtensions`.
      fastErrors =
        flatten (
          map (tgt: optional (!(allPlatformSet ? ${tgt}))
            "Unknown target `${tgt}`, typo or not supported by this version?")
            targets ++
          map (name: optional (!(allComponentSet ? ${name}))
            "Unknown component `${name}`, typo or not support by this version?")
            (profileComponents ++ extensions ++ targetExtensions));

      errors =
        if fastErrors != [] then
          fastErrors
        else
          filter isString result ++
          map (tgt: "Target `${tgt}` is not supported by any components or extensions")
            (filter isTargetUnused targets);

      notes = [
        "note: profile components: ${toString profileComponents}"
      ] ++ optional (targets != []) "note: selected targets: ${toString targets}"
      ++ optional (extensions != []) "note: selected extensions: ${toString extensions}"
      ++ optional (targetExtensions != []) "note: selected targetExtensions: ${toString targetExtensions}"
      ++ flatten (map (platform:
        optional (componentSet ? ${platform})
          "note: components available for ${platform}: ${toString (attrNames componentSet.${platform})}"
        ) (unique ([ rustHostPlatform ] ++ targets)))
      ++ [
        ''
          note: check here to see all targets and which components are available on each targets:
                https://rust-lang.github.io/rustup-components-history
        ''
      ];

    in
      if errors == [] then result
      else throw ''
        Component resolution failed for ${name}
        ${concatStringsSep "\n" (errors ++ notes)}
      '';

  # Genereate the toolchain set from a parsed manifest.
  #
  # Manifest files are organized as follow:
  # { date = "2017-03-03";
  #   pkg.cargo.version= "0.18.0-nightly (5db6d64 2017-03-03)";
  #   pkg.cargo.target.x86_64-unknown-linux-gnu = {
  #     available = true;
  #     hash = "abce..."; # sha256
  #     url = "https://static.rust-lang.org/dist/....tar.gz";
  #     xz_hash = "abce..."; # sha256
  #     xz_url = "https://static.rust-lang.org/dist/....tar.xz";
  #   };
  # }
  #
  # The packages available usually are:
  #   cargo, rust-analysis, rust-docs, rust-src, rust-std, rustc, and
  #   rust, which aggregates them in one package.
  #
  # For each package the following options are available:
  #   extensions        - The extensions that should be installed for the package.
  #                       For example, install the package rust and add the extension rust-src.
  #   targets           - The package will always be installed for the host system, but with this option
  #                       extra targets can be specified, e.g. "mips-unknown-linux-musl". The target
  #                       will only apply to components of the package that support being installed for
  #                       a different architecture. For example, the rust package will install rust-std
  #                       for the host system and the targets.
  #   targetExtensions  - If you want to force extensions to be installed for the given targets, this is your option.
  #                       All extensions in this list will be installed for the target architectures.
  #                       *Attention* If you want to install an extension like rust-src, that has no fixed architecture (arch *),
  #                       you will need to specify this extension in the extensions options or it will not be installed!
  toolchainFromManifest = manifest: let
    maybeRename = name: manifest.renames.${name}.to or name;

    # platform -> true
    # For fail-fast test.
    allPlatformSet =
      listToAttrs (
        flatten (
          mapAttrsToList (compName: { target, ... }:
            map (platform: { name = platform; value = true; })
              (attrNames target)
          ) manifest.pkg));

    # componentName -> true
    # May also contains unavailable components. Just for fail-fast test.
    allComponentSet =
      mapAttrs (compName: _: true)
        (manifest.pkg // manifest.renames);

    # componentSet.x86_64-unknown-linux-gnu.cargo = <derivation>;
    componentSet =
      mapAttrs (platform: _:
        mkComponentSet {
          inherit (manifest) version renames;
          inherit platform;
          srcs = removeNulls
            (mapAttrs (compName: { target, ... }:
              let content = target.${platform} or target."*" or null; in
              if content == null then
                null
              else
                mkComponentSrc {
                  url = content.xz_url;
                  sha256 = content.xz_hash;
                }
            ) manifest.pkg);
        }
      ) allPlatformSet;

    mkProfile = name: profileComponents:
      makeOverridable ({ extensions, targets, targetExtensions }:
        mkAggregated {
          pname = "rust-${name}";
          version = manifest.version;
          availableComponents = componentSet.${rustHostPlatform};
          selectedComponents = resolveComponents {
            name = "rust-${name}-${manifest.version}";
            inherit allPlatformSet allComponentSet componentSet profileComponents targetExtensions;
            inherit (manifest) targetComponentsList;
            extensions = extensions;
            targets = unique ([
              rustHostPlatform # Build script requires host std.
              rustTargetPlatform
            ] ++ targets);
          };
        }
      ) {
        extensions = [];
        targets = [];
        targetExtensions = [];
      };

    profiles = mapAttrs mkProfile manifest.profiles;

    result =
      # Individual components.
      componentSet.${rustHostPlatform} //
      # Profiles.
      profiles // {
        # Legacy support for special pre-aggregated package.
        # It has more components than `default` profile but less than `complete` profile.
        rust =
          let
            pkg = mkProfile "legacy" [ "rust" ];
          in if profiles != {} then
            trace ''
              Rust ${manifest.version}:
              Pre-aggregated package `rust` is not encouraged for stable channel since it contains almost all and uncertain components.
              Consider use `default` profile like `rust-bin.stable.latest.default` and override it with extensions you need.
              See README for more information.
            '' pkg
          else
            pkg;
      };

  in
    # If the platform is not supported for the current version, return nothing here,
    # so others can easily check it by `toolchain ? default`.
    optionalAttrs (componentSet ? ${rustHostPlatform}) result //
    {
      # Internal use.
      _components = componentSet;
      _profiles = profiles;
      _version = manifest.version;
      _manifest = manifest;
    };

  # Same as `toolchainFromManifest` but read from a manifest file.
  toolchainFromManifestFile = path: toolchainFromManifest (fromTOML (readFile path));

  # Override all pkgs of a toolchain set.
  overrideToolchain = attrs: mapAttrs (name: pkg: pkg.override attrs);

  # From a git revision of rustc.
  # This does the same thing as crate `rustup-toolchain-install-master`.
  # But you need to manually provide component hashes.
  fromRustcRev = {
    # Package name of the derivation.
    pname ? "rust-custom",
    # Git revision of rustc.
    rev,
    # Version of the built package.
    version ? substring 0 7 rev,
    # Attrset with component name as key and its SRI hash as value.
    components,
    # Rust target to download.
    target ? rustTargetPlatform
  }: let
    hashToSrc = compName: hash:
      self.fetchurl {
        url = if compName == "rust-src"
          then "https://ci-artifacts.rust-lang.org/rustc-builds/${rev}/${compName}-nightly.tar.xz"
          else "https://ci-artifacts.rust-lang.org/rustc-builds/${rev}/${compName}-nightly-${target}.tar.xz";
        inherit hash;
      };
    components' = mkComponentSet {
      inherit version;
      platform = target;
      srcs = mapAttrs hashToSrc components;
    };
  in
    mkAggregated {
      inherit pname version;
      selectedComponents = attrValues components';
    };

  # Select latest nightly toolchain which makes selected profile builds.
  # Some components are missing in some nightly releases.
  # Usage:
  # `selectLatestNightlyWith (toolchain: toolchain.default.override { extensions = ["llvm-tools-preview"]; })`
  selectLatestNightlyWith = selector:
    let
      nightlyDates = attrNames (removeAttrs self.rust-bin.nightly [ "latest" ]);
      dateLength = length nightlyDates;
      go = idx:
        let ret = selector (self.rust-bin.nightly.${elemAt nightlyDates idx}); in
        if idx == 0 then
          ret
        else if dateLength - idx >= 256 then
          trace "Failed to select nightly version after 100 tries" ret
        else if ret != null && (tryEval ret.drvPath).success then
          ret
        else
          go (idx - 1);
    in
      go (length nightlyDates - 1);

in {
  # For each channel:
  #   rust-bin.stable.latest.{minimal,default,complete} # Profiles.
  #   rust-bin.stable.latest.rust   # Pre-aggregate from upstream.
  #   rust-bin.stable.latest.cargo  # Components...
  #   rust-bin.stable.latest.rustc
  #   rust-bin.stable.latest.rust-docs
  #   ...
  #
  # For a specific version of stable:
  #   rust-bin.stable."1.47.0".default
  #
  # For a specific date of beta:
  #   rust-bin.beta."2021-01-01".default
  #
  # For a specific date of nightly:
  #   rust-bin.nightly."2020-01-01".default
  rust-bin =
    (super.rust-bin or {}) //
    mapAttrs (channel: mapAttrs (version: toolchainFromManifest)) super.rust-bin.manifests //
    {
      inherit fromRustupToolchain fromRustupToolchainFile;
      inherit selectLatestNightlyWith;
      inherit fromRustcRev;
    };

  # All attributes below are for compatiblity with mozilla overlay.

  lib = (super.lib or {}) // {
    rustLib = (super.lib.rustLib or {}) // {
      manifest_v2_url = throw ''
        `manifest_v2_url` is not supported.
        Select a toolchain from `rust-bin` or using `rustChannelOf` instead.
        See also README at https://github.com/oxalica/rust-overlay
      '';
      fromManifest = throw ''
        `fromManifest` is not supported due to network access during evaluation.
        Select a toolchain from `rust-bin` or using `rustChannelOf` instead.
        See also README at https://github.com/oxalica/rust-overlay
      '';
      fromManifestFile = manifestFilePath: { stdenv, fetchurl, patchelf }@deps: trace ''
        `fromManifestFile` is deprecated.
        Select a toolchain from `rust-bin` or using `rustChannelOf` instead.
        See also README at https://github.com/oxalica/rust-overlay
      '' (overrideToolchain deps (toolchainFromManifestFile manifestFilePath));
    };
  };

  rustChannelOf = manifestArgs: toolchainFromManifest (selectManifest manifestArgs);

  latest = (super.latest or {}) // {
    rustChannels = {
      stable = self.rust-bin.stable.latest;
      beta = self.rust-bin.beta.latest;
      nightly = self.rust-bin.nightly.latest;
    };
  };

  rustChannelOfTargets = channel: date: targets:
    (self.rustChannelOf { inherit channel date; })
      .rust.override { inherit targets; };

  rustChannels = self.latest.rustChannels;
}