diff options
Diffstat (limited to 'nix/utils')
| -rw-r--r-- | nix/utils/OWNERS | 3 | ||||
| -rw-r--r-- | nix/utils/default.nix | 176 | ||||
| -rw-r--r-- | nix/utils/tests/.skip-subtree | 1 | ||||
| -rw-r--r-- | nix/utils/tests/default.nix | 110 | ||||
| -rw-r--r-- | nix/utils/tests/directory/file | 0 | ||||
| l--------- | nix/utils/tests/missing | 1 | ||||
| l--------- | nix/utils/tests/symlink-directory | 1 | ||||
| l--------- | nix/utils/tests/symlink-file | 1 | ||||
| l--------- | nix/utils/tests/symlink-symlink-directory | 1 | ||||
| l--------- | nix/utils/tests/symlink-symlink-file | 1 |
10 files changed, 295 insertions, 0 deletions
diff --git a/nix/utils/OWNERS b/nix/utils/OWNERS new file mode 100644 index 0000000000..f16dd105d7 --- /dev/null +++ b/nix/utils/OWNERS @@ -0,0 +1,3 @@ +inherited: true +owners: + - sterni diff --git a/nix/utils/default.nix b/nix/utils/default.nix new file mode 100644 index 0000000000..a29f346519 --- /dev/null +++ b/nix/utils/default.nix @@ -0,0 +1,176 @@ +{ depot, lib, ... }: + +let + /* Get the basename of a store path without + the leading hash. + + Type: (path | drv | string) -> string + + Example: + storePathName ./foo.c + => "foo.c" + + storePathName (writeText "foo.c" "int main() { return 0; }") + => "foo.c" + + storePathName "${hello}/bin/hello" + => "hello" + */ + storePathName = p: + if lib.isDerivation p + then p.name + else if builtins.isPath p + then builtins.baseNameOf p + else if builtins.isString p || (builtins.isAttrs p && (p ? outPath || p ? __toString)) + then + let + strPath = toString p; + # strip leading storeDir and trailing slashes + noStoreDir = lib.removeSuffix "/" + (lib.removePrefix "${builtins.storeDir}/" strPath); + # a basename of a child of a store path isn't really + # referring to a store path, so removing the string + # context is safe (e. g. "hello" for "${hello}/bin/hello"). + basename = builtins.unsafeDiscardStringContext + (builtins.baseNameOf strPath); + in + # If p is a direct child of storeDir, we need to remove + # the leading hash as well to make sure that: + # `storePathName drv == storePathName (toString drv)`. + if noStoreDir == basename + then builtins.substring 33 (-1) basename + else basename + else builtins.throw "Don't know how to get (base)name of " + + lib.generators.toPretty { } p; + + /* Retrieves the drvPath attribute from a given derivation, but ensures that + the resulting string only depends on the `.drv` file in the nix store and + not on its realised outputs as well. + + Type: drv -> string + */ + onlyDrvPath = drv: + let + inherit (drv) drvPath; + unsafeDrvPath = builtins.unsafeDiscardStringContext drvPath; + in + builtins.appendContext unsafeDrvPath { + ${unsafeDrvPath} = { path = true; }; + }; + + /* Query the type of a path exposing the same information as would be by + `builtins.readDir`, but for a single, specific target path. + + The information is returned as a tagged value, i. e. an attribute set with + exactly one attribute where the type of the path is encoded in the name + of the single attribute. The allowed tags and values are as follows: + + * `regular`: is a regular file, always `true` if returned + * `directory`: is a directory, always `true` if returned + * `missing`: path does not exist, always `true` if returned + * `symlink`: path is a symlink, always `true` if returned + + Type: path(-like) -> tag + + `tag` refers to the attribute set format of `//nix/tag`. + + Example: + pathType ./foo.c + => { regular = true; } + + pathType /home/lukas + => { directory = true; } + + pathType ./result + => { symlink = true; } + + pathType ./link-to-file + => { symlink = true; } + + pathType /does/not/exist + => { missing = true; } + + # Check if a path exists + !(pathType /file ? missing) + + # Check if a path is a directory or a symlink to a directory + # A handy shorthand for this is provided as `realPathIsDirectory`. + pathType /path ? directory || (pathType /path).symlink or null == "directory" + + # Match on the result using //nix/tag + nix.tag.match (nix.utils.pathType ./result) { + symlink = _: "symlink"; + directory = _: "directory"; + regular = _: "regular"; + missing = _: "path does not exist"; + } + => "symlink" + + # Query path type + nix.tag.tagName (pathType /path) + */ + pathType = path: + let + # baseNameOf is very annoyed if we proceed with string context. + # We need to call toString to prevent unsafeDiscardStringContext + # from importing a path into store which messes with base- and + # dirname of course. + path' = builtins.unsafeDiscardStringContext (toString path); + # To read the containing directory we absolutely need + # to keep the string context, otherwise a derivation + # would not be realized before our check (at eval time) + containingDir = builtins.readDir (builtins.dirOf path); + # Construct tag to use for the value + thisPathType = containingDir.${builtins.baseNameOf path'} or "missing"; + # Trick to check if the symlink target exists and is a directory: + # if we append a "/." to the string version of the path, Nix won't + # canocalize it (which would strip any "/." in the path), so if + # path' + "/." exists, we know that the symlink points to an existing + # directory. If not, either the target doesn't exist or is a regular file. + # TODO(sterni): is there a way to check reliably if the symlink target exists? + isSymlinkDir = builtins.pathExists (path' + "/."); + in + { + ${thisPathType} = true; + }; + + pathType' = path: + let + p = pathType path; + in + if p ? missing + then builtins.throw "${lib.generators.toPretty {} path} does not exist" + else p; + + /* Check whether the given path is a directory. + Throws if the path in question doesn't exist. + + Type: path(-like) -> bool + */ + isDirectory = path: pathType' path ? directory; + + /* Check whether the given path is a regular file. + Throws if the path in question doesn't exist. + + Type: path(-like) -> bool + */ + isRegularFile = path: pathType' path ? regular; + + /* Check whether the given path is a symbolic link. + Throws if the path in question doesn't exist. + + Type: path(-like) -> bool + */ + isSymlink = path: pathType' path ? symlink; + +in +{ + inherit + storePathName + onlyDrvPath + pathType + isDirectory + isRegularFile + isSymlink + ; +} diff --git a/nix/utils/tests/.skip-subtree b/nix/utils/tests/.skip-subtree new file mode 100644 index 0000000000..1efb1b9476 --- /dev/null +++ b/nix/utils/tests/.skip-subtree @@ -0,0 +1 @@ +subdirectories are just test cases diff --git a/nix/utils/tests/default.nix b/nix/utils/tests/default.nix new file mode 100644 index 0000000000..d5159a8433 --- /dev/null +++ b/nix/utils/tests/default.nix @@ -0,0 +1,110 @@ +{ depot, lib, ... }: + +let + inherit (depot.nix.runTestsuite) + runTestsuite + it + assertEq + assertThrows + assertDoesNotThrow + ; + + inherit (depot.nix.utils) + isDirectory + isRegularFile + isSymlink + pathType + storePathName + onlyDrvPath + ; + + assertUtilsPred = msg: act: exp: [ + (assertDoesNotThrow "${msg} does not throw" act) + (assertEq msg (builtins.tryEval act).value exp) + ]; + + pathPredicates = it "judges paths correctly" (lib.flatten [ + # isDirectory + (assertUtilsPred "directory isDirectory" + (isDirectory ./directory) + true) + (assertUtilsPred "symlink not isDirectory" + (isDirectory ./symlink-directory) + false) + (assertUtilsPred "file not isDirectory" + (isDirectory ./directory/file) + false) + # isRegularFile + (assertUtilsPred "file isRegularFile" + (isRegularFile ./directory/file) + true) + (assertUtilsPred "symlink not isRegularFile" + (isRegularFile ./symlink-file) + false) + (assertUtilsPred "directory not isRegularFile" + (isRegularFile ./directory) + false) + # isSymlink + (assertUtilsPred "symlink to file isSymlink" + (isSymlink ./symlink-file) + true) + (assertUtilsPred "symlink to directory isSymlink" + (isSymlink ./symlink-directory) + true) + (assertUtilsPred "symlink to symlink isSymlink" + (isSymlink ./symlink-symlink-file) + true) + (assertUtilsPred "symlink to missing file isSymlink" + (isSymlink ./missing) + true) + (assertUtilsPred "directory not isSymlink" + (isSymlink ./directory) + false) + (assertUtilsPred "file not isSymlink" + (isSymlink ./directory/file) + false) + # missing files throw + (assertThrows "isDirectory throws on missing file" + (isDirectory ./does-not-exist)) + (assertThrows "isRegularFile throws on missing file" + (isRegularFile ./does-not-exist)) + (assertThrows "isSymlink throws on missing file" + (isSymlink ./does-not-exist)) + ]); + + cheddarStorePath = + builtins.unsafeDiscardStringContext depot.tools.cheddar.outPath; + + cleanedSource = lib.cleanSource ./.; + + storePathNameTests = it "correctly gets the basename of a store path" [ + (assertEq "base name of a derivation" + (storePathName depot.tools.cheddar) + depot.tools.cheddar.name) + (assertEq "base name of a store path string" + (storePathName cheddarStorePath) + depot.tools.cheddar.name) + (assertEq "base name of a path within a store path" + (storePathName "${cheddarStorePath}/bin/cheddar") "cheddar") + (assertEq "base name of a path" + (storePathName ../default.nix) "default.nix") + (assertEq "base name of a cleanSourced path" + (storePathName cleanedSource) + cleanedSource.name) + ]; + + onlyDrvPathTests = it "correctly updates the string context of drvPath" [ + (assertEq "onlyDrvPath only produces path dependencies" + (builtins.all + (dep: dep.path or false) + (builtins.attrValues + (builtins.getContext (onlyDrvPath depot.tools.cheddar)))) + true) + ]; +in + +runTestsuite "nix.utils" [ + pathPredicates + storePathNameTests + onlyDrvPathTests +] diff --git a/nix/utils/tests/directory/file b/nix/utils/tests/directory/file new file mode 100644 index 0000000000..e69de29bb2 --- /dev/null +++ b/nix/utils/tests/directory/file diff --git a/nix/utils/tests/missing b/nix/utils/tests/missing new file mode 120000 index 0000000000..cfa0a46515 --- /dev/null +++ b/nix/utils/tests/missing @@ -0,0 +1 @@ +does-not-exist \ No newline at end of file diff --git a/nix/utils/tests/symlink-directory b/nix/utils/tests/symlink-directory new file mode 120000 index 0000000000..6d0450cc24 --- /dev/null +++ b/nix/utils/tests/symlink-directory @@ -0,0 +1 @@ +directory \ No newline at end of file diff --git a/nix/utils/tests/symlink-file b/nix/utils/tests/symlink-file new file mode 120000 index 0000000000..cd5d01792a --- /dev/null +++ b/nix/utils/tests/symlink-file @@ -0,0 +1 @@ +directory/file \ No newline at end of file diff --git a/nix/utils/tests/symlink-symlink-directory b/nix/utils/tests/symlink-symlink-directory new file mode 120000 index 0000000000..5d6ba5247e --- /dev/null +++ b/nix/utils/tests/symlink-symlink-directory @@ -0,0 +1 @@ +symlink-directory \ No newline at end of file diff --git a/nix/utils/tests/symlink-symlink-file b/nix/utils/tests/symlink-symlink-file new file mode 120000 index 0000000000..f8d9ce3659 --- /dev/null +++ b/nix/utils/tests/symlink-symlink-file @@ -0,0 +1 @@ +symlink-file \ No newline at end of file |