1 files changed, 214 insertions, 0 deletions
diff --git a/engine/dconf-engine-profile.c b/engine/dconf-engine-profile.c
new file mode 100644
index 0000000..0413f32
--- /dev/null
+++ b/engine/dconf-engine-profile.c
@@ -0,0 +1,214 @@
+/*
+ * Copyright © 2010 Codethink Limited
+ * Copyright © 2012 Canonical Limited
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the licence, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ * Author: Ryan Lortie <desrt@desrt.ca>
+ */
+
+#include "dconf-engine-profile.h"
+
+#include <string.h>
+#include <stdio.h>
+
+#include "dconf-engine-source.h"
+
+/* This comment attempts to document the exact semantics of
+ * profile-loading.
+ *
+ * In no situation should the result of profile loading be an abort.
+ * There must be a defined outcome for all possible situations.
+ * Warnings may be issued to stderr, however.
+ *
+ * The first step is to determine what profile is to be used.  If a
+ * profile is explicitly specified by the API then it has the top
+ * priority.  Otherwise, if the DCONF_PROFILE environment variable is
+ * set, it takes next priority.
+ *
+ * In both of those cases, if the named profile starts with a slash
+ * character then it is taken to be an absolute pathname.  If it does
+ * not start with a slash then it is assumed to specify a profile file
+ * relative to /etc/dconf/profile/ (ie: DCONF_PROFILE=test for profile
+ * file /etc/dconf/profile/test).
+ *
+ * If opening the profile file fails then the null profile is used.
+ * This is a profile that contains zero sources.  All keys will be
+ * unwritable and all reads will return NULL.
+ *
+ * In the case that no explicit profile was given and DCONF_PROFILE is
+ * unset, dconf attempts to open and use a profile called "user" (ie:
+ * profile file /etc/dconf/profile/user).  If that fails then the
+ * fallback is to act as if the profile file existed and contained a
+ * single line: "user-db:user".
+ *
+ * Note that the fallback case for a missing profile file is different
+ * in the case where a profile was explicitly specified (either by the
+ * API or the environment) and the case where one was not.
+ *
+ * Once a profile file is opened, each line is treated as a possible
+ * source.  Comments and empty lines are ignored.
+ *
+ * All valid source specification lines need to start with 'user-db:' or
+ * 'system-db:'.  If a line doesn't start with one of these then it gets
+ * ignored.  If all the lines in the file get ignored then the result is
+ * effectively the null profile.
+ *
+ * If the first source is a "user-db:" then the resulting profile will
+ * be writable.  No profile starting with a "system-db:" source can ever
+ * be writable.
+ *
+ * Note: even if the source fails to initialise (due to a missing file,
+ * for example) it will remain in the source list.  This could have a
+ * performance cost: in the case of a system-db, for example, dconf will
+ * check if the file has come into existence on every read.
+ */
+
+static DConfEngineSource **
+dconf_engine_null_profile (gint *n_sources)
+{
+  *n_sources = 0;
+
+  return NULL;
+}
+
+static DConfEngineSource **
+dconf_engine_default_profile (gint *n_sources)
+{
+  DConfEngineSource **sources;
+
+  sources = g_new (DConfEngineSource *, 1);
+  sources[0] = dconf_engine_source_new_default ();
+  *n_sources = 1;
+
+  return sources;
+}
+
+static DConfEngineSource *
+dconf_engine_profile_handle_line (gchar *line)
+{
+  gchar *end;
+
+  /* remove whitespace at the front */
+  while (g_ascii_isspace (*line))
+    line++;
+
+  /* find the end of the line (or start of comments) */
+  end = line + strcspn (line, "#\n");
+
+  /* remove whitespace at the end */
+  while (end > line && g_ascii_isspace (end[-1]))
+    end--;
+
+  /* if we're left with nothing, return NULL */
+  if (line == end)
+    return NULL;
+
+  *end = '\0';
+
+  return dconf_engine_source_new (line);
+}
+
+static DConfEngineSource **
+dconf_engine_read_profile_file (FILE *file,
+                                gint *n_sources)
+{
+  DConfEngineSource **sources;
+  gchar line[80];
+  gint n = 0, a;
+
+  sources = g_new (DConfEngineSource *, (a = 4));
+
+  while (fgets (line, sizeof line, file))
+    {
+      DConfEngineSource *source;
+
+      /* The input file has long lines. */
+      if G_UNLIKELY (!strchr (line, '\n'))
+        {
+          GString *long_line;
+
+          long_line = g_string_new (line);
+          while (fgets (line, sizeof line, file))
+            {
+              g_string_append (long_line, line);
+              if (strchr (line, '\n'))
+                break;
+            }
+
+          source = dconf_engine_profile_handle_line (long_line->str);
+          g_string_free (long_line, TRUE);
+        }
+
+      else
+        source = dconf_engine_profile_handle_line (line);
+
+      if (source != NULL)
+        {
+          if (n == a)
+            sources = g_renew (DConfEngineSource *, sources, a *= 2);
+
+          sources[n++] = source;
+        }
+    }
+
+  *n_sources = n;
+
+  return g_realloc_n (sources, n, sizeof (DConfEngineSource *));
+}
+
+DConfEngineSource **
+dconf_engine_profile_open (const gchar *profile,
+                           gint        *n_sources)
+{
+  DConfEngineSource **sources;
+  FILE *file;
+
+  if (profile == NULL)
+    profile = g_getenv ("DCONF_PROFILE");
+
+  if (profile == NULL)
+    {
+      file = fopen ("/etc/dconf/profile/user", "r");
+
+      /* Only in the case that no profile was specified do we use this
+       * fallback.
+       */
+      if (file == NULL)
+        return dconf_engine_default_profile (n_sources);
+    }
+  else if (profile[0] != '/')
+    {
+      gchar *filename = g_build_filename ("/etc/dconf/profile", profile, NULL);
+      file = fopen (filename, "r");
+      g_free (filename);
+    }
+  else
+    file = fopen (profile, "r");
+
+  if (file != NULL)
+    {
+      sources = dconf_engine_read_profile_file (file, n_sources);
+      fclose (file);
+    }
+  else
+    {
+      g_warning ("unable to open named profile (%s): using the null configuration.", profile);
+      sources = dconf_engine_null_profile (n_sources);
+    }
+
+  return sources;
+}