[gimp/metadata-browser] app: Don't overload head_size with different meanings

[Roman Joost <romanofski src gnome org>]

commit 3fbbe2d1861cabfdcfadc775d5aa792b8ba981f9
Author: Mukund Sivaraman <muks banu com>
Date:   Sun Oct 2 18:35:26 2011 +0530

    app: Don't overload head_size with different meanings
    
    The code in file_procedure_find() tries to lazy-open the image file, so
    it's not opened if unnecessary. To keep track of whether the image was
    opened or not, it overrides head_size to keep track of this. head_size
    is also assigned the return value of fread() in the loop. The patch
    separates this by introducing another variable.
    
    I think it's best to move the file opening code outside the while loop,
    as it's most likely bound to be opened anyway, and the penalty is not
    too bad.

 app/file/file-procedure.c |   25 +++++++++++--------------
 1 files changed, 11 insertions(+), 14 deletions(-)
---
diff --git a/app/file/file-procedure.c b/app/file/file-procedure.c
index 146d9d7..375339a 100644
--- a/app/file/file-procedure.c
+++ b/app/file/file-procedure.c
@@ -113,7 +113,8 @@ file_procedure_find (GSList       *procs,
     {
       GimpPlugInProcedure *size_matched_proc = NULL;
       FILE                *ifp               = NULL;
-      gint                 head_size         = -2;
+      gboolean             opened            = FALSE;
+      gint                 head_size         = 0;
       gint                 size_match_count  = 0;
       guchar               head[256];
 
@@ -124,21 +125,17 @@ file_procedure_find (GSList       *procs,
 
           if (file_proc->magics_list)
             {
-              if (head_size == -2)
+              if (G_UNLIKELY (!opened))
                 {
-                  head_size = 0;
-
-                  if ((ifp = g_fopen (filename, "rb")) != NULL)
-                    {
-                      head_size = fread ((gchar *) head, 1, sizeof (head), ifp);
-                    }
+                  ifp = g_fopen (filename, "rb");
+                  if (ifp != NULL)
+                    head_size = fread ((gchar *) head, 1, sizeof (head), ifp);
                   else
-                    {
-                      g_set_error_literal (error,
-                                           G_FILE_ERROR,
-                                           g_file_error_from_errno (errno),
-                                           g_strerror (errno));
-                    }
+                    g_set_error_literal (error,
+                                         G_FILE_ERROR,
+                                         g_file_error_from_errno (errno),
+                                         g_strerror (errno));
+                  opened = TRUE;
                 }
 
               if (head_size >= 4)