add std/appdirs (#20618)

lib/std/appdirs.nim

@@ -0,0 +1,73 @@
+from std/private/osappdirs import nil
+import std/paths
+import std/envvars
+
+proc getHomeDir*(): Path {.inline, tags: [ReadEnvEffect, ReadIOEffect].} =
+  ## Returns the home directory of the current user.
+  ##
+  ## This proc is wrapped by the `expandTilde proc`_
+  ## for the convenience of processing paths coming from user configuration files.
+  ##
+  ## See also:
+  ## * `getConfigDir proc`_
+  ## * `getTempDir proc`_
+  result = Path(osappdirs.getHomeDir())
+
+proc getConfigDir*(): Path {.inline, tags: [ReadEnvEffect, ReadIOEffect].} =
+  ## Returns the config directory of the current user for applications.
+  ##
+  ## On non-Windows OSs, this proc conforms to the XDG Base Directory
+  ## spec. Thus, this proc returns the value of the `XDG_CONFIG_HOME` environment
+  ## variable if it is set, otherwise it returns the default configuration
+  ## directory ("~/.config/").
+  ##
+  ## An OS-dependent trailing slash is always present at the end of the
+  ## returned string: `\\` on Windows and `/` on all other OSs.
+  ##
+  ## See also:
+  ## * `getHomeDir proc`_
+  ## * `getTempDir proc`_
+  result = Path(osappdirs.getConfigDir())
+
+proc getCacheDir*(): Path {.inline.} =
+  ## Returns the cache directory of the current user for applications.
+  ##
+  ## This makes use of the following environment variables:
+  ##
+  ## * On Windows: `getEnv("LOCALAPPDATA")`
+  ##
+  ## * On macOS: `getEnv("XDG_CACHE_HOME", getEnv("HOME") / "Library/Caches")`
+  ##
+  ## * On other platforms: `getEnv("XDG_CACHE_HOME", getEnv("HOME") / ".cache")`
+  ##
+  ## **See also:**
+  ## * `getHomeDir proc`_
+  ## * `getTempDir proc`_
+  ## * `getConfigDir proc`_
+  # follows https://crates.io/crates/platform-dirs
+  result = Path(osappdirs.getCacheDir())
+
+proc getCacheDir*(app: Path): Path {.inline.} =
+  ## Returns the cache directory for an application `app`.
+  ##
+  ## * On Windows, this uses: `getCacheDir() / app / "cache"`
+  ## * On other platforms, this uses: `getCacheDir() / app`
+  result = Path(osappdirs.getCacheDir(app.string))
+
+proc getTempDir*(): Path {.inline, tags: [ReadEnvEffect, ReadIOEffect].} =
+  ## Returns the temporary directory of the current user for applications to
+  ## save temporary files in.
+  ##
+  ## On Windows, it calls [GetTempPath](https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-gettemppathw).
+  ## On Posix based platforms, it will check `TMPDIR`, `TEMP`, `TMP` and `TEMPDIR` environment variables in order.
+  ## On all platforms, `/tmp` will be returned if the procs fails.
+  ##
+  ## You can override this implementation
+  ## by adding `-d:tempDir=mytempname` to your compiler invocation.
+  ##
+  ## .. Note:: This proc does not check whether the returned path exists.
+  ##
+  ## See also:
+  ## * `getHomeDir proc`_
+  ## * `getConfigDir proc`_
+  result = Path(osappdirs.getTempDir())

tests/stdlib/tfilesanddirs.nim

@@ -1,4 +1,4 @@
-import std/[paths, files, dirs]
+import std/[paths, files, dirs, appdirs]
 
 from stdtest/specialpaths import buildDir
 import std/[syncio, assertions]
@@ -21,3 +21,16 @@ block fileOperations:
     let fh = open(string(dname/file), fmReadWrite) # createFile
     fh.close()
     doAssert fileExists(Path(dname/file))
+
+block: # getCacheDir
+  doAssert getCacheDir().dirExists
+
+block: # moveFile
+  let tempDir = getTempDir() / Path("D20221022T151608")
+  createDir(tempDir)
+  defer: removeDir(tempDir)
+
+block: # moveDir
+  let tempDir = getTempDir() / Path("D20220609T161443")
+  createDir(tempDir)
+  defer: removeDir(tempDir)