Fix error messages when readdir cannot open a directory on MS-Windows

 src/dired.c (read_dirent): Accept an additional argument
 FIRST_ENTRY.  If readdir fails with ENOENT or EACCES the first
 time it is called, report the error as if it happened in
 open_directory.
 (directory_files_internal, file_name_completion): Adjust callers
 or read_dirent.

2 files changed, 29 insertions, 5 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 67b6fa01b59..fc4258c9bfb 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2015-01-30  Eli Zaretskii  <eliz@gnu.org>
+
+	* dired.c (read_dirent): Accept an additional argument
+	FIRST_ENTRY.  If readdir fails with ENOENT or EACCES the first
+	time it is called, report the error as if it happened in
+	open_directory.
+	(directory_files_internal, file_name_completion): Adjust callers
+	or read_dirent.
+
 2015-01-30  Paul Eggert  <eggert@cs.ucla.edu>
 
 	Refactor calls to opendir for simplicity
diff --git a/src/dired.c b/src/dired.c
index 7982c1fb8eb..56d6de2d352 100644
--- a/src/dired.c
+++ b/src/dired.c
@@ -124,10 +124,11 @@ directory_files_internal_unwind (void *dh)
 
 /* Return the next directory entry from DIR; DIR's name is DIRNAME.
    If there are no more directory entries, return a null pointer.
-   Signal any unrecoverable errors.  */
+   Signal any unrecoverable errors.  FIRST_ENTRY true means this is
+   the first call after open_directory.  */
 
 static struct dirent *
-read_dirent (DIR *dir, Lisp_Object dirname)
+read_dirent (DIR *dir, Lisp_Object dirname, bool first_entry)
 {
   while (true)
     {
@@ -136,7 +137,16 @@ read_dirent (DIR *dir, Lisp_Object dirname)
       if (dp || errno == 0)
 	return dp;
       if (! (errno == EAGAIN || errno == EINTR))
-	report_file_error ("Reading directory", dirname);
+	{
+	  /* The MS-Windows implementation of 'opendir' doesn't
+	     actually open a directory until the first call to
+	     'readdir'.  If 'readdir' fails to open the directory, it
+	     sets errno to ENOENT or EACCES, see w32.c.  */
+	  if (first_entry && (errno == ENOENT || errno == EACCES))
+	    report_file_error ("Opening directory", dirname);
+	  else
+	    report_file_error ("Reading directory", dirname);
+	}
       QUIT;
     }
 }
@@ -239,7 +249,8 @@ directory_files_internal (Lisp_Object directory, Lisp_Object full,
     needsep = 1;
 
   /* Loop reading directory entries.  */
-  for (struct dirent *dp; (dp = read_dirent (d, directory)); )
+  bool first_entry = true;
+  for (struct dirent *dp; (dp = read_dirent (d, directory, first_entry)); )
     {
       ptrdiff_t len = dirent_namelen (dp);
       Lisp_Object name = make_unibyte_string (dp->d_name, len);
@@ -247,6 +258,8 @@ directory_files_internal (Lisp_Object directory, Lisp_Object full,
       struct gcpro gcpro1, gcpro2;
       GCPRO2 (finalname, name);
 
+      first_entry = false;
+
       /* Note: DECODE_FILE can GC; it should protect its argument,
 	 though.  */
       name = DECODE_FILE (name);
@@ -486,11 +499,13 @@ file_name_completion (Lisp_Object file, Lisp_Object dirname, bool all_flag,
   record_unwind_protect_ptr (directory_files_internal_unwind, d);
 
   /* Loop reading directory entries.  */
-  for (struct dirent *dp; (dp = read_dirent (d, dirname)); )
+  bool first_entry = true;
+  for (struct dirent *dp; (dp = read_dirent (d, dirname, first_entry)); )
     {
       ptrdiff_t len = dirent_namelen (dp);
       bool canexclude = 0;
 
+      first_entry = false;
       QUIT;
       if (len < SCHARS (encoded_file)
 	  || (scmp (dp->d_name, SSDATA (encoded_file),