[libgit2-glib] Use delta and hunk cache during diff foreach

[Jesse van den Kieboom <jessevdk src gnome org>]

commit ba08e5d924fe51c952dfe0ad976e9ebbdd0ccf2f
Author: Jesse van den Kieboom <jessevdk gnome org>
Date:   Mon Aug 15 15:17:20 2016 +0200

    Use delta and hunk cache during diff foreach

 libgit2-glib/ggit-diff.c |   81 ++++++++++++++++++++++++++++++++++-----------
 1 files changed, 61 insertions(+), 20 deletions(-)
---
diff --git a/libgit2-glib/ggit-diff.c b/libgit2-glib/ggit-diff.c
index 7adb055..c7e9707 100644
--- a/libgit2-glib/ggit-diff.c
+++ b/libgit2-glib/ggit-diff.c
@@ -54,6 +54,9 @@ typedef struct {
 
        gpointer user_data;
 
+       GHashTable *cached_deltas;
+       GHashTable *cached_hunks;
+
        GgitDiffFileCallback file_cb;
        GgitDiffBinaryCallback binary_cb;
        GgitDiffHunkCallback hunk_cb;
@@ -68,6 +71,50 @@ enum
        PROP_REPOSITORY
 };
 
+static GgitDiffDelta *
+wrap_diff_delta_cached (CallbackWrapperData  *data,
+                        const git_diff_delta *delta)
+{
+       GgitDiffDelta *gdelta;
+
+       if (!delta)
+       {
+               return NULL;
+       }
+
+       gdelta = g_hash_table_lookup (data->cached_deltas, delta);
+
+       if (!gdelta)
+       {
+               gdelta = _ggit_diff_delta_wrap (delta);
+               g_hash_table_insert (data->cached_deltas, (gpointer) delta, gdelta);
+       }
+
+       return gdelta;
+}
+
+static GgitDiffHunk *
+wrap_diff_hunk_cached (CallbackWrapperData *data,
+                       const git_diff_hunk *hunk)
+{
+       GgitDiffHunk *ghunk;
+
+       if (!hunk)
+       {
+               return NULL;
+       }
+
+       ghunk = g_hash_table_lookup (data->cached_hunks, hunk);
+
+       if (!ghunk)
+       {
+               ghunk = _ggit_diff_hunk_wrap (hunk);
+               g_hash_table_insert (data->cached_hunks, (gpointer) hunk, ghunk);
+       }
+
+       return ghunk;
+}
+
 static gint
 ggit_diff_file_callback_wrapper (const git_diff_delta *delta,
                                  gfloat                progress,
@@ -77,7 +124,7 @@ ggit_diff_file_callback_wrapper (const git_diff_delta *delta,
        GgitDiffDelta *gdelta;
        gint ret;
 
-       gdelta = _ggit_diff_delta_wrap (delta);
+       gdelta = wrap_diff_delta_cached (data, delta);
 
        data->encoding = NULL;
 
@@ -114,8 +161,6 @@ ggit_diff_file_callback_wrapper (const git_diff_delta *delta,
 
        ret = data->file_cb (gdelta, progress, data->user_data);
 
-       ggit_diff_delta_unref (gdelta);
-
        return ret;
 }
 
@@ -129,12 +174,11 @@ ggit_diff_binary_callback_wrapper (const git_diff_delta  *delta,
        GgitDiffBinary *gbinary;
        gint ret;
 
-       gdelta = _ggit_diff_delta_wrap (delta);
+       gdelta = wrap_diff_delta_cached (data, delta);
        gbinary = _ggit_diff_binary_wrap (binary);
 
        ret = data->binary_cb (gdelta, gbinary, data->user_data);
 
-       ggit_diff_delta_unref (gdelta);
        ggit_diff_binary_unref (gbinary);
 
        return ret;
@@ -150,14 +194,11 @@ ggit_diff_hunk_callback_wrapper (const git_diff_delta *delta,
        GgitDiffHunk *ghunk;
        gint ret;
 
-       gdelta = _ggit_diff_delta_wrap (delta);
-       ghunk = _ggit_diff_hunk_wrap (hunk);
+       gdelta = wrap_diff_delta_cached (data, delta);
+       ghunk = wrap_diff_hunk_cached (data, hunk);
 
        ret = data->hunk_cb (gdelta, ghunk, data->user_data);
 
-       ggit_diff_hunk_unref (ghunk);
-       ggit_diff_delta_unref (gdelta);
-
        return ret;
 }
 
@@ -169,7 +210,7 @@ ggit_diff_line_callback_wrapper (const git_diff_delta *delta,
 {
        CallbackWrapperData *data = user_data;
        GgitDiffDelta *gdelta;
-       GgitDiffHunk *ghunk;
+       GgitDiffHunk *ghunk = NULL;
        GgitDiffLine *gline;
        gint ret;
        const gchar *encoding = NULL;
@@ -186,8 +227,9 @@ ggit_diff_line_callback_wrapper (const git_diff_delta *delta,
                encoding = priv->encoding;
        }
 
-       gdelta = _ggit_diff_delta_wrap (delta);
-       ghunk = hunk == NULL ? NULL : _ggit_diff_hunk_wrap (hunk);
+       gdelta = wrap_diff_delta_cached (data, delta);
+       ghunk = wrap_diff_hunk_cached (data, hunk);
+
        gline = line == NULL ? NULL : _ggit_diff_line_wrap (line, encoding);
 
        ret = data->line_cb (gdelta, ghunk, gline, data->user_data);
@@ -197,13 +239,6 @@ ggit_diff_line_callback_wrapper (const git_diff_delta *delta,
                ggit_diff_line_unref (gline);
        }
 
-       if (ghunk != NULL)
-       {
-               ggit_diff_hunk_unref (ghunk);
-       }
-
-       ggit_diff_delta_unref (gdelta);
-
        return ret;
 }
 
@@ -575,6 +610,9 @@ ggit_diff_foreach (GgitDiff              *diff,
        wrapper_data.diff = diff;
        wrapper_data.encoding = NULL;
 
+       wrapper_data.cached_deltas = g_hash_table_new_full (g_direct_hash, g_direct_equal, NULL, 
(GDestroyNotify) ggit_diff_delta_unref);
+       wrapper_data.cached_hunks = g_hash_table_new_full (g_direct_hash, g_direct_equal, NULL, 
(GDestroyNotify) ggit_diff_hunk_unref);
+
        if (file_cb != NULL)
        {
                real_file_cb = ggit_diff_file_callback_wrapper;
@@ -604,6 +642,9 @@ ggit_diff_foreach (GgitDiff              *diff,
                                real_hunk_cb, real_line_cb,
                                &wrapper_data);
 
+       g_hash_table_destroy (wrapper_data.cached_deltas);
+       g_hash_table_destroy (wrapper_data.cached_hunks);
+
        if (ret != GIT_OK)
        {
                _ggit_error_set (error, ret);