stdlib/os: handle symlinks in copy/move functions

- Added optional `options` argument to `copyFile`, `copyFileToDir`, and
  `copyFileWithPermissions`. By default, symlinks are followed (copy files
  symlinks point to).
- `copyDir` and `copyDirWithPermissions` copy symlinks as symlinks (instead of
  skipping them as it was before).
- `moveFile` and `moveDir` move symlinks as symlinks (instead of skipping them
  sometimes as it was before).
- Added optional `followSymlinks` argument to `setFilePermissions`.

See also: nim-lang/RFCs#319

Co-authored-by: Timothee Cour <[email protected]>

Author: Roman Inflianskas

changelog.md

@@ -111,6 +111,16 @@ with other backends. see #9125. Use `-d:nimLegacyJsRound` for previous behavior.
 
 - Removed the optional `longestMatch` parameter of the `critbits._WithPrefix` iterators (it never worked reliably)
 
+
+- Added optional `options` argument to `copyFile`, `copyFileToDir`, and
+  `copyFileWithPermissions`. By default, symlinks are followed (copy files
+  symlinks point to).
+- `copyDir` and `copyDirWithPermissions` copy symlinks as symlinks (instead of
+  skipping them as it was before).
+- `moveFile` and `moveDir` move symlinks as they are (instead of skipping them
+  sometimes as it was before).
+- Added optional `followSymlinks` argument to `setFilePermissions`.
+
 ## Language changes
 
 - `nimscript` now handles `except Exception as e`.

lib/posix/posix.nim

@@ -586,6 +586,8 @@ proc fstatvfs*(a1: cint, a2: var Statvfs): cint {.
   importc, header: "<sys/statvfs.h>".}
 
 proc chmod*(a1: cstring, a2: Mode): cint {.importc, header: "<sys/stat.h>", sideEffect.}
+when hasLchmod:
+  proc lchmod*(a1: cstring, a2: Mode): cint {.importc, header: "<sys/stat.h>", sideEffect.}
 proc fchmod*(a1: cint, a2: Mode): cint {.importc, header: "<sys/stat.h>", sideEffect.}
 proc fstat*(a1: cint, a2: var Stat): cint {.importc, header: "<sys/stat.h>", sideEffect.}
 proc lstat*(a1: cstring, a2: var Stat): cint {.importc, header: "<sys/stat.h>", sideEffect.}

lib/posix/posix_haiku.nim

@@ -13,6 +13,7 @@ when defined(nimHasStyleChecks):
 const
   hasSpawnH = true # should exist for every Posix system nowadays
   hasAioH = defined(linux)
+  hasLchmod* = false
 
 when defined(linux) and not defined(android):
   # On Linux:

lib/posix/posix_linux_amd64.nim

@@ -15,6 +15,7 @@
 const
   hasSpawnH = not defined(haiku) # should exist for every Posix system nowadays
   hasAioH = defined(linux)
+  hasLchmod* = false
 
 # On Linux:
 # timer_{create,delete,settime,gettime},

lib/posix/posix_macos_amd64.nim

@@ -13,6 +13,7 @@ when defined(nimHasStyleChecks):
 const
   hasSpawnH = true # should exist for every Posix system nowadays
   hasAioH = false
+  hasLchmod* = true
 
 type
   DIR* {.importc: "DIR", header: "<dirent.h>",

lib/posix/posix_nintendoswitch.nim

@@ -12,6 +12,7 @@
 const
   hasSpawnH = true
   hasAioH = false
+  hasLchmod* = false
 
 type
   DIR* {.importc: "DIR", header: "<dirent.h>",

lib/posix/posix_openbsd_amd64.nim

@@ -13,6 +13,7 @@ when defined(nimHasStyleChecks):
 const
   hasSpawnH = true # should exist for every Posix system nowadays
   hasAioH = false
+  hasLchmod* = false
 
 type
   DIR* {.importc: "DIR", header: "<dirent.h>",

lib/posix/posix_other.nim

@@ -14,10 +14,12 @@ when defined(freertos):
   const
     hasSpawnH = false # should exist for every Posix system nowadays
     hasAioH = false
+    hasLchmod* = false
 else:
   const
     hasSpawnH = true # should exist for every Posix system nowadays
     hasAioH = defined(linux)
+    hasLchmod* = false
 
 when defined(linux) and not defined(android):
   # On Linux: