Add splitpath(p::AbstractString) to Base.Filesystem. (#28156)

base/exports.jl

@@ -832,6 +832,7 @@ export
     splitdir,
     splitdrive,
     splitext,
+    splitpath,
 
 # filesystem operations
     cd,

base/path.jl

@@ -15,7 +15,8 @@ export
     relpath,
     splitdir,
     splitdrive,
-    splitext
+    splitext,
+    splitpath
 
 if Sys.isunix()
     const path_separator    = "/"
@@ -129,6 +130,12 @@ julia> splitdir("/home/myuser")
 """
 function splitdir(path::String)
     a, b = splitdrive(path)
+    _splitdir_nodrive(a,b)
+end
+
+# Common splitdir functionality without splitdrive, needed for splitpath.
+_splitdir_nodrive(path::String) = _splitdir_nodrive("", path)
+function _splitdir_nodrive(a::String, b::String)
     m = match(path_dir_splitter,b)
     m === nothing && return (a,b)
     a = string(a, isempty(m.captures[1]) ? m.captures[2][1] : m.captures[1])
@@ -196,6 +203,41 @@ function pathsep(paths::AbstractString...)
     return path_separator
 end
 
+"""
+    splitpath(path::AbstractString) -> Vector{String}
+
+Split a file path into all its path components. This is the opposite of
+`joinpath`. Returns an array of substrings, one for each directory or file in
+the path, including the root directory if present.
+
+# Examples
+```jldoctest
+julia> splitpath("/home/myuser/example.jl")
+4-element Array{String,1}:
+ "/"
+ "home"
+ "myuser"
+ "example.jl"
+```
+"""
+function splitpath(p::String)
+    drive, p = splitdrive(p)
+    out = String[]
+    isempty(p) && (pushfirst!(out,p))  # "" means the current directory.
+    while !isempty(p)
+        dir, base = _splitdir_nodrive(p)
+        dir == p && (pushfirst!(out, dir); break)  # Reached root node.
+        if !isempty(base)  # Skip trailing '/' in basename
+            pushfirst!(out, base)
+        end
+        p = dir
+    end
+    if !isempty(drive)  # Tack the drive back on to the first element.
+        out[1] = drive*out[1]  # Note that length(out) is always >= 1.
+    end
+    return out
+end
+
 joinpath(a::AbstractString) = a
 
 """

doc/src/base/file.md

@@ -62,4 +62,5 @@ Base.Filesystem.expanduser
 Base.Filesystem.splitdir
 Base.Filesystem.splitdrive
 Base.Filesystem.splitext
+Base.Filesystem.splitpath
 ```

test/path.jl

@@ -85,6 +85,42 @@
     end
     @test relpath(S(joinpath("foo","bar")), S("foo")) == "bar"
 
+    @testset "splitpath" begin
+        @test splitpath(joinpath("a","b","c")) == ["a", "b", "c"]
+        @test splitpath("") == [""]
+
+        @test splitpath(joinpath("cats are", "gr8t")) == ["cats are", "gr8t"]
+        @test splitpath(joinpath("  ", " ")) == ["  ", " "]
+
+        # Unix-style paths are understood by all systems.
+        @test splitpath("/a/b") == ["/", "a", "b"]
+        @test splitpath("/") == ["/"]
+        @test splitpath("a/") == ["a"]
+        @test splitpath("a/b/") == ["a", "b"]
+        @test splitpath("a.dir/b.txt") == ["a.dir", "b.txt"]
+        @test splitpath("///") == ["/"]
+        @test splitpath("///a///b///") == ["/", "a", "b"]
+
+        if Sys.iswindows()
+            @test splitpath("C:\\\\a\\b\\c") == ["C:\\", "a", "b", "c"]
+            @test splitpath("C:\\\\") == ["C:\\"]
+            @test splitpath("J:\\") == ["J:\\"]
+            @test splitpath("C:") == ["C:"]
+            @test splitpath("C:a") == ["C:a"]
+            @test splitpath("C:a\\b") == ["C:a", "b"]
+
+            @test splitpath("a\\") == ["a"]
+            @test splitpath("a\\\\b\\\\") == ["a","b"]
+            @test splitpath("a.dir\\b.txt") == ["a.dir", "b.txt"]
+            @test splitpath("\\a\\b\\") == ["\\", "a","b"]
+            @test splitpath("\\\\a\\b") == ["\\\\a\\b"]  # This is actually a valid drive name in windows.
+
+            @test splitpath("/a/b\\c/d\\\\e") == ["/", "a", "b", "c", "d", "e"]
+            @test splitpath("/\\/\\") == ["/"]
+            @test splitpath("\\/\\a/\\//b") == ["\\","a","b"]
+        end
+    end
+
     @testset "splitting" begin
         @test joinpath(splitdir(S(homedir()))...) == homedir()
         @test string(splitdrive(S(homedir()))...) == homedir()