Optimization to load only needed .pc files

Currently pkg-config scans all .pc files from the search path during
initialization. That makes some of the code simpler and works fine when
there are not many .pc files on the system. When there are a lot of .pc
files, then this represents a lot of wasted effort.

Rework the package gathering so that it happens as needed. To support
the --list-all mode, the scanning at initialization can still be done.

https://bugs.freedesktop.org/show_bug.cgi?id=98215

3 files changed, 59 insertions, 98 deletions

diff --git a/main.c b/main.c
index 227ed35..9b27d9a 100644
--- a/main.c
+++ b/main.c
@@ -643,7 +643,7 @@ main (int argc, char **argv)
         return 1;
     }
 
-  package_init ();
+  package_init (want_list);
 
   if (want_list)
     {
diff --git a/pkg.c b/pkg.c
index 5aa4380..a8a3fcd 100644
--- a/pkg.c
+++ b/pkg.c
@@ -43,11 +43,8 @@
 static void verify_package (Package *pkg);
 
 static GHashTable *packages = NULL;
-static GHashTable *locations = NULL;
-static GHashTable *path_positions = NULL;
 static GHashTable *globals = NULL;
 static GList *search_dirs = NULL;
-static int scanned_dir_count = 0;
 
 gboolean disable_uninstalled = FALSE;
 gboolean ignore_requires = FALSE;
@@ -121,6 +118,8 @@ name_ends_in_uninstalled (const char *str)
     return FALSE;
 }
 
+static Package *
+internal_get_package (const char *name, gboolean warn);
 
 /* Look for .pc files in the given directory and add them into
  * locations, ignoring duplicates
@@ -129,7 +128,7 @@ static void
 scan_dir (char *dirname)
 {
   GDir *dir;
-  const gchar *d_name;
+  const gchar *filename;
 
   int dirnamelen = strlen (dirname);
   /* Use a copy of dirname cause Win32 opendir doesn't like
@@ -161,59 +160,20 @@ scan_dir (char *dirname)
   dir = g_dir_open (dirname_copy, 0 , NULL);
   g_free (dirname_copy);
 
-  scanned_dir_count += 1;
-
   if (!dir)
     {
-      debug_spew ("Cannot open directory #%i '%s' in package search path: %s\n",
-                  scanned_dir_count, dirname, g_strerror (errno));
+      debug_spew ("Cannot open directory '%s' in package search path: %s\n",
+                  dirname, g_strerror (errno));
       return;
     }
 
-  debug_spew ("Scanning directory #%i '%s'\n", scanned_dir_count, dirname);
-  
-  while ((d_name = g_dir_read_name(dir)))
-    {
-      int len = strlen (d_name);
+  debug_spew ("Scanning directory '%s'\n", dirname);
 
-      if (ends_in_dotpc (d_name))
-        {
-          char *pkgname = g_malloc (len - EXT_LEN + 1);
-
-          debug_spew ("File '%s' appears to be a .pc file\n", d_name);
-          
-          strncpy (pkgname, d_name, len - EXT_LEN);
-          pkgname[len-EXT_LEN] = '\0';
-
-          if (g_hash_table_lookup (locations, pkgname))
-            {
-              debug_spew ("File '%s' ignored, we already know about package '%s'\n", d_name, pkgname);
-              g_free (pkgname);
-            }
-          else
-            {
-              char *filename = g_malloc (dirnamelen + 1 + len + 1);
-              strncpy (filename, dirname, dirnamelen);
-              filename[dirnamelen] = G_DIR_SEPARATOR;
-              strcpy (filename + dirnamelen + 1, d_name);
-              
-	      if (g_file_test(filename, G_FILE_TEST_IS_REGULAR) == TRUE) {
-		  g_hash_table_insert (locations, pkgname, filename);
-		  g_hash_table_insert (path_positions, pkgname,
-				       GINT_TO_POINTER (scanned_dir_count));
-		  debug_spew ("Will find package '%s' in file '%s'\n",
-			      pkgname, filename);
-	      } else {
-		  debug_spew ("Ignoring '%s' while looking for '%s'; not a "
-			      "regular file.\n", pkgname, filename);
-	      }
-	    }
-        }
-      else
-        {
-          debug_spew ("Ignoring file '%s' in search directory; not a .pc file\n",
-                      d_name);
-        }
+  while ((filename = g_dir_read_name(dir)))
+    {
+      char *path = g_build_filename (dirname, filename, NULL);
+      internal_get_package (path, FALSE);
+      g_free (path);
     }
   g_dir_close (dir);
 }
@@ -243,31 +203,31 @@ add_virtual_pkgconfig_package (void)
 }
 
 void
-package_init ()
+package_init (gboolean want_list)
 {
-  static gboolean initted = FALSE;
-
-  if (!initted)
-    {
-      initted = TRUE;
+  if (packages)
+    return;
       
-      packages = g_hash_table_new (g_str_hash, g_str_equal);
-      locations = g_hash_table_new (g_str_hash, g_str_equal);
-      path_positions = g_hash_table_new (g_str_hash, g_str_equal);
-      
-      add_virtual_pkgconfig_package ();
+  packages = g_hash_table_new (g_str_hash, g_str_equal);
 
-      g_list_foreach (search_dirs, (GFunc)scan_dir, NULL);
-    }
+  if (want_list)
+    g_list_foreach (search_dirs, (GFunc)scan_dir, NULL);
+  else
+    /* Should not add virtual pkgconfig package when listing to be
+     * compatible with old code that only listed packages from real
+     * files */
+    add_virtual_pkgconfig_package ();
 }
 
 static Package *
 internal_get_package (const char *name, gboolean warn)
 {
   Package *pkg = NULL;
-  char *key;
-  const char *location;
+  char *key = NULL;
+  char *location = NULL;
+  unsigned int path_position = 0;
   GList *iter;
+  GList *dir_iter;
   
   pkg = g_hash_table_lookup (packages, name);
 
@@ -280,7 +240,8 @@ internal_get_package (const char *name, gboolean warn)
   if ( ends_in_dotpc (name) )
     {
       debug_spew ("Considering '%s' to be a filename rather than a package name\n", name);
-      location = name;
+      location = g_strdup (name);
+      key = g_strdup (name);
     }
   else
     {
@@ -303,7 +264,18 @@ internal_get_package (const char *name, gboolean warn)
             }
         }
       
-      location = g_hash_table_lookup (locations, name);
+      for (dir_iter = search_dirs; dir_iter != NULL;
+           dir_iter = g_list_next (dir_iter))
+        {
+          path_position++;
+          location = g_strdup_printf ("%s%c%s.pc", (char*)dir_iter->data,
+                                      G_DIR_SEPARATOR, name);
+          if (g_file_test (location, G_FILE_TEST_IS_REGULAR))
+            break;
+          g_free (location);
+          location = NULL;
+        }
+
     }
   
   if (location == NULL)
@@ -317,21 +289,13 @@ internal_get_package (const char *name, gboolean warn)
       return NULL;
     }
 
-  if (location != name)
+  if (key == NULL)
     key = g_strdup (name);
   else
     {
       /* need to strip package name out of the filename */
-      int len = strlen (name);
-      const char *end = name + (len - EXT_LEN);
-      const char *start = end;
-
-      while (start != name && *start != G_DIR_SEPARATOR)
-        --start;
-
-      g_assert (end >= start);
-
-      key = g_strndup (start, end - start);
+      key = g_path_get_basename (name);
+      key[strlen (key) - EXT_LEN] = '\0';
     }
 
   debug_spew ("Reading '%s' from file '%s'\n", name, location);
@@ -339,17 +303,18 @@ internal_get_package (const char *name, gboolean warn)
                             ignore_private_libs, ignore_requires_private);
   g_free (key);
 
+  if (pkg != NULL && strstr (location, "uninstalled.pc"))
+    pkg->uninstalled = TRUE;
+
+  g_free (location);
+
   if (pkg == NULL)
     {
       debug_spew ("Failed to parse '%s'\n", location);
       return NULL;
     }
 
-  if (strstr (location, "uninstalled.pc"))
-    pkg->uninstalled = TRUE;
-
-  pkg->path_position =
-    GPOINTER_TO_INT (g_hash_table_lookup (path_positions, pkg->key));
+  pkg->path_position = path_position;
 
   debug_spew ("Path position of '%s' is %d\n",
               pkg->key, pkg->path_position);
@@ -1170,19 +1135,15 @@ max_len_foreach (gpointer key, gpointer value, gpointer data)
 static void
 packages_foreach (gpointer key, gpointer value, gpointer data)
 {
-  Package *pkg = get_package (key);
-
-  if (pkg != NULL)
-    {
-      char *pad;
+  Package *pkg = value;
+  char *pad;
 
-      pad = g_strnfill (GPOINTER_TO_INT (data) - strlen (pkg->key), ' ');
+  pad = g_strnfill (GPOINTER_TO_INT (data) - strlen (pkg->key), ' ');
       
-      printf ("%s%s%s - %s\n",
-              pkg->key, pad, pkg->name, pkg->description);
+  printf ("%s%s%s - %s\n",
+          pkg->key, pad, pkg->name, pkg->description);
 
-      g_free (pad);
-    }
+  g_free (pad);
 }
 
 void
@@ -1193,8 +1154,8 @@ print_package_list (void)
   ignore_requires = TRUE;
   ignore_requires_private = TRUE;
 
-  g_hash_table_foreach (locations, max_len_foreach, &mlen);
-  g_hash_table_foreach (locations, packages_foreach, GINT_TO_POINTER (mlen + 1));
+  g_hash_table_foreach (packages, max_len_foreach, &mlen);
+  g_hash_table_foreach (packages, packages_foreach, GINT_TO_POINTER (mlen + 1));
 }
 
 void
diff --git a/pkg.h b/pkg.h
index 13cc2c6..c6732bd 100644
--- a/pkg.h
+++ b/pkg.h
@@ -98,7 +98,7 @@ char *   packages_get_var          (GList      *pkgs,
 
 void add_search_dir (const char *path);
 void add_search_dirs (const char *path, const char *separator);
-void package_init (void);
+void package_init (gboolean want_list);
 int compare_versions (const char * a, const char *b);
 gboolean version_test (ComparisonType comparison,
                        const char *a,