[gnome-builder] makecache: walk through makecache a line at a time

[Christian Hergert <chergert src gnome org>]

commit ba60f6edbd59f18f6db5b3eea7adc8e2440b0f02
Author: Christian Hergert <christian hergert me>
Date:   Tue Mar 24 15:11:54 2015 -0700

    makecache: walk through makecache a line at a time
    
    This allows us to avoid using MULTI_LINE regex (not really a big deal), but
    more importantly, it allows us to check for additional types of matches
    while walking through the content.
    
    In particular, we need to track the current subdir, which will be doable
    now in a single pass through the data.

 libide/autotools/ide-makecache.c |   93 +++++++++++++++++++++++++++++++++-----
 1 files changed, 81 insertions(+), 12 deletions(-)
---
diff --git a/libide/autotools/ide-makecache.c b/libide/autotools/ide-makecache.c
index 5554bcd..254ea5d 100644
--- a/libide/autotools/ide-makecache.c
+++ b/libide/autotools/ide-makecache.c
@@ -63,6 +63,13 @@ typedef struct
   gchar  *relative_path;
 } FileFlagsLookup;
 
+typedef struct
+{
+  const gchar *contents;
+  gsize        length;
+  gssize       pos;
+} ReadLines;
+
 G_DEFINE_TYPE (IdeMakecache, ide_makecache, IDE_TYPE_OBJECT)
 
 enum {
@@ -74,6 +81,60 @@ enum {
 static GParamSpec *gParamSpecs [LAST_PROP];
 
 static void
+read_lines_init (ReadLines   *rl,
+                 const gchar *contents,
+                 gsize        length)
+{
+  g_assert (rl);
+  g_assert (contents);
+
+  if (length < G_MAXSIZE)
+    {
+      rl->contents = contents;
+      rl->length = length;
+      rl->pos = 0;
+    }
+  else
+    {
+      rl->contents = NULL;
+      rl->length = 0;
+      rl->pos = 0;
+    }
+}
+
+static const gchar *
+read_lines_next (ReadLines *rl,
+                 gsize     *length)
+{
+  const gchar *ret = NULL;
+
+  g_assert (rl);
+  g_assert (length);
+
+  if ((rl->contents == NULL) || (rl->pos >= rl->length))
+    {
+      *length = 0;
+      return NULL;
+    }
+
+  ret = &rl->contents [rl->pos];
+
+  for (; rl->pos < rl->length; rl->pos++)
+    {
+      if (rl->contents [rl->pos] == '\n')
+        {
+          *length = &rl->contents [rl->pos] - ret;
+          rl->pos++;
+          return ret;
+        }
+    }
+
+  *length = &rl->contents [rl->pos] - ret;
+
+  return ret;
+}
+
+static void
 file_flags_lookup_free (gpointer data)
 {
   FileFlagsLookup *lookup = data;
@@ -212,7 +273,10 @@ ide_makecache_get_file_targets_searched (IdeMakecache *self,
   g_autoptr(GMatchInfo) match_info = NULL;
   g_autoptr(GHashTable) found = NULL;
   g_autoptr(GPtrArray) targets = NULL;
+  const gchar *line;
+  ReadLines rl = { 0 };
   gsize len;
+  gsize line_len;
 
   IDE_ENTRY;
 
@@ -222,7 +286,7 @@ ide_makecache_get_file_targets_searched (IdeMakecache *self,
   escaped = g_regex_escape_string (path, -1);
   regexstr = g_strdup_printf ("^([^:\n ]+):.*\\b(%s)\\b", escaped);
 
-  regex = g_regex_new (regexstr, G_REGEX_MULTILINE, 0, NULL);
+  regex = g_regex_new (regexstr, 0, 0, NULL);
   if (!regex)
     IDE_RETURN (NULL);
 
@@ -242,22 +306,27 @@ ide_makecache_get_file_targets_searched (IdeMakecache *self,
   }
 #endif
 
-  if (g_regex_match_full (regex, content, len, 0, 0, &match_info, NULL))
+  read_lines_init (&rl, content, len);
+
+  while ((line = read_lines_next (&rl, &line_len)))
     {
-      while (g_match_info_matches (match_info))
+      if (g_regex_match_full (regex, line, line_len, 0, 0, &match_info, NULL))
         {
-          g_autofree gchar *target = NULL;
+          while (g_match_info_matches (match_info))
+            {
+              g_autofree gchar *target = NULL;
 
-          target = g_match_info_fetch (match_info, 1);
+              target = g_match_info_fetch (match_info, 1);
 
-          if (is_target_interesting (target) && !g_hash_table_contains (found, target))
-            {
-              g_hash_table_insert (found, target, NULL);
-              g_ptr_array_add (targets, target);
-              target = NULL;
-            }
+              if (is_target_interesting (target) && !g_hash_table_contains (found, target))
+                {
+                  g_hash_table_insert (found, target, NULL);
+                  g_ptr_array_add (targets, target);
+                  target = NULL;
+                }
 
-          g_match_info_next (match_info, NULL);
+              g_match_info_next (match_info, NULL);
+            }
         }
     }