io.pathnames: Add canonicalize-path.

The idea is to make a canonical representation of any path, taking into
account . and .. and unicode-prefix on Windows.

The use case is in a shell you have a current-directory and you can do
crazy commands like ``cd ../foo/bar/baz/../.././././`` and get the
canonical/shortened directory name. You can also use this word to
compare if two paths are the same.

basis/io/files/windows/windows.factor

@@ -8,7 +8,7 @@ io.files.types io.pathnames io.ports io.streams.c io.streams.null
 io.timeouts kernel libc literals locals math math.bitwise namespaces
 sequences specialized-arrays system threads tr vectors windows
 windows.errors windows.handles windows.kernel32 windows.shell32
-windows.time windows.types windows.winsock ;
+windows.time windows.types windows.winsock splitting ;
 SPECIALIZED-ARRAY: ushort
 IN: io.files.windows
 
@@ -326,11 +326,14 @@ M: windows root-directory? ( path -- ? )
         [ drop f ]
     } cond ;
 
-: prepend-prefix ( string -- string' )
+: prepend-unicode-prefix ( string -- string' )
     dup unicode-prefix head? [
         unicode-prefix prepend
     ] unless ;
 
+: remove-unicode-prefix ( string -- string' )
+    unicode-prefix ?head drop ;
+
 TR: normalize-separators "/" "\\" ;
 
 <PRIVATE
@@ -340,13 +343,20 @@ TR: normalize-separators "/" "\\" ;
 
 PRIVATE>
 
+M: windows canonicalize-path
+    remove-unicode-prefix canonicalize-path* ;
+
+M: object root-path remove-unicode-prefix root-path* ;
+
+M: object relative-path remove-unicode-prefix relative-path* ;
+
 M: windows normalize-path ( string -- string' )
     dup unc-path? [
         normalize-separators
     ] [
         absolute-path
         normalize-separators
-        prepend-prefix
+        prepend-unicode-prefix
     ] if ;
 
 <PRIVATE

core/io/pathnames/pathnames-tests.factor

@@ -1,6 +1,6 @@
 USING: io.backend io.directories io.files.private io.files.temp
-io.files.unique io.pathnames kernel locals math namespaces
-system tools.test ;
+io.files.unique io.pathnames kernel locals math multiline
+namespaces sequences system tools.test ;
 
 { "passwd" } [ "/etc/passwd" file-name ] unit-test
 { "awk" } [ "/usr/libexec/awk/" file-name ] unit-test
@@ -81,3 +81,80 @@ H{
 
 { t } [ "~" home [ "foo" append-path ] bi@ [ normalize-path ] same? ] unit-test
 { t } [ os windows? "~\\~/" "~/~/" ? "~" "~" append-path [ path-components ] same? ] unit-test
+
+! Absolute paths
+os windows? [
+    { "c:/" } [ "c:/" canonicalize-path ] unit-test
+    { "c:/" } [ "c:/." canonicalize-path ] unit-test
+    { "c:/" } [ "c:/.." canonicalize-path ] unit-test
+    { "c:/" } [ "c:/Users/.." canonicalize-path ] unit-test
+    { "c:/" } [ "c:/Users/../" canonicalize-path ] unit-test
+    { "c:/" } [ "c:/Users/../." canonicalize-path ] unit-test
+    { "c:/" } [ "c:/Users/.././" canonicalize-path ] unit-test
+    { "c:/" } [ "c:/Users/.././././././" canonicalize-path ] unit-test
+    { "c:/" } [ "c:/Users/../././/////./././/././././//././././././." canonicalize-path ] unit-test
+    { "c:/" } [ "c:/Users/../../../..////.././././././/../" canonicalize-path ] unit-test
+    { "c:/Users" } [ "c:/Users/../../../Users" canonicalize-path ] unit-test
+
+    { "c:/Users" } [ "c:/Users" canonicalize-path ] unit-test
+    { "c:/Users" } [ "c:/Users/." canonicalize-path ] unit-test
+    { "c:/Users\\foo\\bar" } [ "c:/Users/foo/bar" canonicalize-path ] unit-test
+] [
+    { "/" } [ "/" canonicalize-path ] unit-test
+    { "/" } [ "/." canonicalize-path ] unit-test
+    { "/" } [ "/.." canonicalize-path ] unit-test
+    { "/" } [ "/Users/.." canonicalize-path ] unit-test
+    { "/" } [ "/Users/../" canonicalize-path ] unit-test
+    { "/" } [ "/Users/../." canonicalize-path ] unit-test
+    { "/" } [ "/Users/.././" canonicalize-path ] unit-test
+    { "/" } [ "/Users/.././././././" canonicalize-path ] unit-test
+    { "/" } [ "/Users/../././/////./././/././././//././././././." canonicalize-path ] unit-test
+    { "/" } [ "/Users/../../../..////.././././././/../" canonicalize-path ] unit-test
+    { "/Users" } [ "/Users/../../../Users" canonicalize-path ] unit-test
+
+    { "/Users" } [ "/Users" canonicalize-path ] unit-test
+    { "/Users" } [ "/Users/." canonicalize-path ] unit-test
+    { "/Users/foo/bar" } [ "/Users/foo/bar" canonicalize-path ] unit-test
+] if
+
+
+! Relative paths
+{ "." } [ f canonicalize-path ] unit-test
+{ "." } [ "" canonicalize-path ] unit-test
+{ "." } [ "." canonicalize-path ] unit-test
+{ "." } [ "./" canonicalize-path ] unit-test
+{ "." } [ "./." canonicalize-path ] unit-test
+{ ".." } [ ".." canonicalize-path ] unit-test
+{ ".." } [ "../" canonicalize-path ] unit-test
+{ ".." } [ "../." canonicalize-path ] unit-test
+{ ".." } [ ".././././././//." canonicalize-path ] unit-test
+
+{ t } [ "../.." canonicalize-path { "../.." "..\\.." } member? ] unit-test
+{ t } [ "../../" canonicalize-path { "../.." "..\\.." } member? ] unit-test
+{ t } [ "../.././././/./././" canonicalize-path { "../.." "..\\.." } member? ] unit-test
+
+
+! Root paths
+os windows? [
+    { "d:\\" } [ "d:\\" root-path ] unit-test
+    { "d:\\" } [ "d:\\\\\\\\//////" root-path ] unit-test
+    { "c:\\" } [ "c:\\Users\\merlen" root-path ] unit-test
+    { "c:\\" } [ "c:\\\\\\//Users//\\//merlen//" root-path ] unit-test
+    { "d:\\" } [ "d:\\././././././/../../../" root-path ] unit-test
+    { "d:\\" } [ "d:\\merlen\\dog" root-path ] unit-test
+
+    { "d:\\" } [ "\\\\?\\d:\\" root-path ] unit-test
+    { "d:\\" } [ "\\\\?\\d:\\\\\\\\//////" root-path ] unit-test
+    { "c:\\" } [ "\\\\?\\c:\\Users\\merlen" root-path ] unit-test
+    { "c:\\" } [ "\\\\?\\c:\\\\\\//Users//\\//merlen//" root-path ] unit-test
+    { "d:\\" } [ "\\\\?\\d:\\././././././/../../../" root-path ] unit-test
+    { "d:\\" } [ "\\\\?\\d:\\merlen\\dog" root-path ] unit-test
+] [
+    { "/" } [ "/" root-path ] unit-test
+    { "/" } [ "//" root-path ] unit-test
+    { "/" } [ "/Users" root-path ] unit-test
+    { "/" } [ "//Users" root-path ] unit-test
+    { "/" } [ "/Users/foo/bar////././." root-path ] unit-test
+    { "/" } [ "/Users/foo/bar////.//../../../../../../////./." root-path ] unit-test
+    { "/" } [ "/Users/////" root-path ] unit-test
+] if

core/io/pathnames/pathnames.factor

@@ -1,7 +1,7 @@
 ! Copyright (C) 2004, 2009 Slava Pestov, Doug Coleman.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors combinators io.backend kernel math math.order
-namespaces sequences splitting strings system ;
+USING: accessors combinators io.backend io.files.windows kernel
+math math.order namespaces sequences splitting strings system ;
 IN: io.pathnames
 
 SYMBOL: current-directory
@@ -166,6 +166,53 @@ M: string absolute-path
 M: object normalize-path ( path -- path' )
     absolute-path ;
 
+: root-path* ( path -- path' )
+    dup absolute-path? [
+        dup [ path-separator? ] find
+        drop 1 + head
+    ] when ;
+
+HOOK: root-path os ( path -- path' )
+
+M: object root-path root-path* ;
+
+: relative-path* ( path -- relative-path )
+    dup absolute-path? [
+        dup [ path-separator? ] find
+        drop 1 + tail
+    ] when ;
+
+HOOK: relative-path os ( path -- path' )
+
+M: object relative-path relative-path* ;
+
+: canonicalize-path* ( path -- path' )
+    [
+        relative-path
+        [ path-separator? ] split-when
+        [ { "." "" } member? ] reject
+        V{ } clone [
+            dup ".." = [
+                over empty?
+                [ over push ]
+                [ over ?last ".." = [ over push ] [ drop dup pop* ] if ] if
+            ] [
+                over push
+            ] if
+        ] reduce
+    ] keep dup absolute-path? [
+        [
+            [ ".." = ] trim-head
+            path-separator join
+        ] dip root-path prepend-path
+    ] [
+        drop path-separator join [ "." ] when-empty
+    ] if ;
+
+HOOK: canonicalize-path io-backend ( path -- path' )
+
+M: object canonicalize-path canonicalize-path* ;
+
 TUPLE: pathname string ;
 
 C: <pathname> pathname