[gimp] libgimpbase: Support changing GIMP2_DIRECTORY at run-time

[Martin Nordholts <martinn src gnome org>]

commit 5d9dde1d479bf153f63ee9c03571069fcb8266b2
Author: Martin Nordholts <martinn src gnome org>
Date:   Fri Jan 29 17:47:30 2010 +0100

    libgimpbase: Support changing GIMP2_DIRECTORY at run-time
    
    In order to be able to change GIMP2_DIRECTORY during run-time, check
    for changes to GIMP2_DIRECTORY in gimp_directory().
    
    This is typically useful in test case where you could read from one
    GIMP2_DIRECTORY at start-up and then write to a different
    GIMP2_DIRECTORY at shut down.
    
    The documentation for this function does not suggest that the value is
    cached and thus the old behavior can be considered a bug. It is hard
    to imagine why anyone would change GIMP2_DIRECTORY at run-time in a
    script for example and *not* expect gimp_directory() to return the
    updated gimp_dir.

 libgimpbase/gimpenv.c |   42 ++++++++++++++++++++++++++++++++++++++----
 1 files changed, 38 insertions(+), 4 deletions(-)
---
diff --git a/libgimpbase/gimpenv.c b/libgimpbase/gimpenv.c
index d2448ba..bdbfda0 100644
--- a/libgimpbase/gimpenv.c
+++ b/libgimpbase/gimpenv.c
@@ -151,16 +151,50 @@ gimp_env_init (gboolean plug_in)
 const gchar *
 gimp_directory (void)
 {
-  static gchar *gimp_dir = NULL;
+  static gchar *gimp_dir          = NULL;
+  static gchar *last_env_gimp_dir = NULL;
 
   const gchar  *env_gimp_dir;
   const gchar  *home_dir;
 
+  env_gimp_dir = g_getenv ("GIMP2_DIRECTORY");
+
   if (gimp_dir)
-    return gimp_dir;
+    {
+      gboolean gimp2_directory_changed = FALSE;
 
-  env_gimp_dir = g_getenv ("GIMP2_DIRECTORY");
-  home_dir     = g_get_home_dir ();
+      /* We have constructed the gimp_dir already. We can return
+       * gimp_dir unless some parameter gimp_dir depends on has
+       * changed. For now we just check for changes to GIMP2_DIRECTORY
+       */
+      gimp2_directory_changed =
+        (env_gimp_dir == NULL &&
+         last_env_gimp_dir != NULL) ||
+        (env_gimp_dir != NULL &&
+         last_env_gimp_dir == NULL) ||
+        (env_gimp_dir != NULL &&
+         last_env_gimp_dir != NULL &&
+         strcmp (env_gimp_dir, last_env_gimp_dir) != 0);
+
+      if (! gimp2_directory_changed)
+        {
+          return gimp_dir;
+        }
+      else
+        {
+          /* Free the old gimp_dir and go on to update it */
+          g_free (gimp_dir);
+          gimp_dir = NULL;
+        }
+    }
+
+  /* Remember the GIMP2_DIRECTORY to next invocation so we can check
+   * if it changes
+   */
+  g_free (last_env_gimp_dir);
+  last_env_gimp_dir = g_strdup (env_gimp_dir);
+
+  home_dir = g_get_home_dir ();
 
   if (env_gimp_dir)
     {