lib/std: handle `last_error` for FileStat-related services in Path

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/lib/standard/file.nit b/lib/standard/file.nit
index 03a671e..b06a93d 100644 (file)
--- a/lib/standard/file.nit
+++ b/lib/standard/file.nit
@@ -385,11 +385,14 @@ class Path
        var last_error: nullable IOError = null is writable
 
        # Does the file at `path` exists?
+       #
+       # If the file does not exists, `last_error` is set to the information.
        fun exists: Bool do return stat != null
 
        # Information on the file at `self` following symbolic links
        #
        # Returns `null` if there is no file at `self`.
+       # `last_error` is updated to contains the error information on error, and null on success.
        #
        #     assert "/etc/".to_path.stat.is_dir
        #     assert "/etc/issue".to_path.stat.is_file
@@ -401,12 +404,18 @@ class Path
        # if stat != null then # Does `p` exist?
        #     print "It's size is {stat.size}"
        #     if stat.is_dir then print "It's a directory"
+       # else
+       #     print p.last_error.to_s
        # end
        # ~~~
        fun stat: nullable FileStat
        do
                var stat = path.to_cstring.file_stat
-               if stat.address_is_null then return null
+               if stat.address_is_null then
+                       last_error = new IOError("Cannot open `{path}`: {sys.errno.strerror}")
+                       return null
+               end
+               last_error = null
                return new FileStat(stat)
        end
 
@@ -416,7 +425,11 @@ class Path
        fun link_stat: nullable FileStat
        do
                var stat = path.to_cstring.file_lstat
-               if stat.address_is_null then return null
+               if stat.address_is_null then
+                       last_error = new IOError("Cannot open `{path}`: {sys.errno.strerror}")
+                       return null
+               end
+               last_error = null
                return new FileStat(stat)
        end