libuv_readlink_function

base/exports.jl

@@ -1280,6 +1280,7 @@ export
     mv,
     operm,
     pwd,
+    readlink,
     rm,
     stat,
     symlink,

base/fs.jl

@@ -23,6 +23,7 @@ export File,
        rename,
        sendfile,
        symlink,
+       readlink,
        chmod,
        futime,
        JL_O_WRONLY,
@@ -163,6 +164,18 @@ end
 @windowsxp_only symlink(p::AbstractString, np::AbstractString) =
     error("WindowsXP does not support soft symlinks")
 
+function readlink(path::AbstractString)
+    req = Libc.malloc(_sizeof_uv_fs)
+    ret = ccall(:uv_fs_readlink, Int32,
+        (Ptr{Void}, Ptr{Void}, Ptr{UInt8}, Ptr{Void}),
+        eventloop(), req, path, C_NULL)
+    uv_error("readlink", ret)
+    tgt = bytestring(ccall(:jl_uv_fs_t_ptr, Ptr{Cchar}, (Ptr{Void}, ), req))
+    ccall(:uv_fs_req_cleanup, Void, (Ptr{Void}, ), req)
+    Libc.free(req)
+    tgt
+end
+
 function chmod(p::AbstractString, mode::Integer)
     err = ccall(:jl_fs_chmod, Int32, (Ptr{UInt8}, Cint), p, mode)
     uv_error("chmod",err)

doc/helpdb.jl

@@ -5021,6 +5021,12 @@ Millisecond(v)
 
 "),
 
+("Base","readlink","readlink(path) -> AbstractString
+
+    Returns the value of a symbolic link \"path\".
+
+"),
+
 ("Base","chmod","chmod(path, mode)
 
    Change the permissions mode of \"path\" to \"mode\". Only integer

doc/stdlib/file.rst

@@ -40,6 +40,10 @@
       This function raises an error under operating systems that do not support
       soft symbolic links, such as Windows XP.
 
+.. function:: readlink(path) -> AbstractString
+
+   Returns the value of a symbolic link ``path``.
+
 .. function:: chmod(path, mode)
 
    Change the permissions mode of ``path`` to ``mode``. Only integer ``mode``\ s

test/file.jl

@@ -1,24 +1,40 @@
 #############################################
 # Create some temporary files & directories #
 #############################################
-
 starttime = time()
+pwd_ = pwd()
 dir = mktempdir()
 file = joinpath(dir, "afile.txt")
 close(open(file,"w")) # like touch, but lets the operating system update the timestamp for greater precision on some platforms (windows)
 
-@unix_only begin
-    link = joinpath(dir, "afilelink.txt")
-    symlink(file, link)
-end
-
 subdir = joinpath(dir, "adir")
 mkdir(subdir)
+subdir2 = joinpath(dir, "adir2")
+mkdir(subdir2)
+
 @non_windowsxp_only begin
     dirlink = joinpath(dir, "dirlink")
     symlink(subdir, dirlink)
+    # relative link
+    cd(subdir)
+    relsubdirlink = joinpath(subdir, "rel_subdirlink")
+    reldir = joinpath("..", "adir2")
+    symlink(reldir, relsubdirlink)
+    cd(pwd_)
 end
 
+@unix_only begin
+    link = joinpath(dir, "afilelink.txt")
+    symlink(file, link)
+    # relative link
+    cd(subdir)
+    rellink = joinpath(subdir, "rel_afilelink.txt")
+    relfile = joinpath("..", "afile.txt")
+    symlink(relfile, rellink)
+    cd(pwd_)
+end
+
+
 #######################################################################
 # This section tests some of the features of the stat-based file info #
 #######################################################################
@@ -50,9 +66,12 @@ end
 
 # test links
 @unix_only @test islink(link) == true
+@unix_only @test readlink(link) == file
+
 @non_windowsxp_only begin
     @test islink(dirlink) == true
     @test isdir(dirlink) == true
+    @test readlink(dirlink) == subdir * @windows? "\\" : ""
 end
 
 # rename file
@@ -412,11 +431,17 @@ test_LibcFILE(Libc.FILE(f,Libc.modestr(true,false)))
 ############
 # Clean up #
 ############
-@unix_only rm(link)
-@non_windowsxp_only rm(dirlink)
-
+@unix_only begin
+    rm(link)
+    rm(rellink)
+end
+@non_windowsxp_only begin
+    rm(dirlink)
+    rm(relsubdirlink)
+end
 rm(file)
 rm(subdir)
+rm(subdir2)
 rm(dir)
 
 # The following fail on Windows with "stat: operation not permitted (EPERM)"