diffcore-rename: split out the delta counting code.

This is to rework diffcore break/rename/copy detection code
so that it does not affected when deltifier code gets improved.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/Makefile b/Makefile
index 19578fc..a5eb0c4 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -196,7 +196,8 @@ LIB_H = \
 
 DIFF_OBJS = \
        diff.o diffcore-break.o diffcore-order.o diffcore-pathspec.o \
-       diffcore-pickaxe.o diffcore-rename.o tree-diff.o combine-diff.o
+       diffcore-pickaxe.o diffcore-rename.o tree-diff.o combine-diff.o \
+       diffcore-delta.o
 
 LIB_OBJS = \
        blob.o commit.o connect.o count-delta.o csum-file.o \

diff --git a/diffcore-break.c b/diffcore-break.c
index 95b5eb4..0fc2b86 100644 (file)
--- a/diffcore-break.c
+++ b/diffcore-break.c
@@ -4,8 +4,6 @@
 #include "cache.h"
 #include "diff.h"
 #include "diffcore.h"
-#include "delta.h"
-#include "count-delta.h"
 
 static int should_break(struct diff_filespec *src,
                        struct diff_filespec *dst,
@@ -47,7 +45,6 @@ static int should_break(struct diff_filespec *src,
         * The value we return is 1 if we want the pair to be broken,
         * or 0 if we do not.
         */
-       void *delta;
        unsigned long delta_size, base_size, src_copied, literal_added;
        int to_break = 0;
 
@@ -69,19 +66,11 @@ static int should_break(struct diff_filespec *src,
        if (base_size < MINIMUM_BREAK_SIZE)
                return 0; /* we do not break too small filepair */
 
-       delta = diff_delta(src->data, src->size,
-                          dst->data, dst->size,
-                          &delta_size, 0);
-       if (!delta)
-               return 0; /* error but caught downstream */
-
-       /* Estimate the edit size by interpreting delta. */
-       if (count_delta(delta, delta_size,
-                       &src_copied, &literal_added)) {
-               free(delta);
-               return 0; /* we cannot tell */
-       }
-       free(delta);
+       if (diffcore_count_changes(src->data, src->size,
+                                  dst->data, dst->size,
+                                  0,
+                                  &src_copied, &literal_added))
+               return 0;
 
        /* Compute merge-score, which is "how much is removed
         * from the source material".  The clean-up stage will

diff --git a/diffcore-delta.c b/diffcore-delta.c
new file mode 100644 (file)
index 0000000..1e6a691
--- /dev/null
+++ b/diffcore-delta.c
@@ -0,0 +1,43 @@
+#include "cache.h"
+#include "diff.h"
+#include "diffcore.h"
+#include "delta.h"
+#include "count-delta.h"
+
+static int diffcore_count_changes_1(void *src, unsigned long src_size,
+                                   void *dst, unsigned long dst_size,
+                                   unsigned long delta_limit,
+                                   unsigned long *src_copied,
+                                   unsigned long *literal_added)
+{
+       void *delta;
+       unsigned long delta_size;
+
+       delta = diff_delta(src, src_size,
+                          dst, dst_size,
+                          &delta_size, delta_limit);
+       if (!delta)
+               /* If delta_limit is exceeded, we have too much differences */
+               return -1;
+
+       /* Estimate the edit size by interpreting delta. */
+       if (count_delta(delta, delta_size, src_copied, literal_added)) {
+               free(delta);
+               return -1;
+       }
+       free(delta);
+       return 0;
+}
+
+int diffcore_count_changes(void *src, unsigned long src_size,
+                          void *dst, unsigned long dst_size,
+                          unsigned long delta_limit,
+                          unsigned long *src_copied,
+                          unsigned long *literal_added)
+{
+       return diffcore_count_changes_1(src, src_size,
+                                       dst, dst_size,
+                                       delta_limit,
+                                       src_copied,
+                                       literal_added);
+}

diff --git a/diffcore-rename.c b/diffcore-rename.c
index ffd126a..55cf1c3 100644 (file)
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -4,8 +4,6 @@
 #include "cache.h"
 #include "diff.h"
 #include "diffcore.h"
-#include "delta.h"
-#include "count-delta.h"
 
 /* Table of rename/copy destinations */
 
@@ -135,7 +133,6 @@ static int estimate_similarity(struct diff_filespec *src,
         * match than anything else; the destination does not even
         * call into this function in that case.
         */
-       void *delta;
        unsigned long delta_size, base_size, src_copied, literal_added;
        unsigned long delta_limit;
        int score;
@@ -165,28 +162,13 @@ static int estimate_similarity(struct diff_filespec *src,
        if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
                return 0; /* error but caught downstream */
 
-       delta_limit = base_size * (MAX_SCORE-minimum_score) / MAX_SCORE;
-       delta = diff_delta(src->data, src->size,
-                          dst->data, dst->size,
-                          &delta_size, delta_limit);
-       if (!delta)
-               /* If delta_limit is exceeded, we have too much differences */
-               return 0;
-
-       /* A delta that has a lot of literal additions would have
-        * big delta_size no matter what else it does.
-        */
-       if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE) {
-               free(delta);
-               return 0;
-       }
 
-       /* Estimate the edit size by interpreting delta. */
-       if (count_delta(delta, delta_size, &src_copied, &literal_added)) {
-               free(delta);
+       delta_limit = base_size * (MAX_SCORE-minimum_score) / MAX_SCORE;
+       if (diffcore_count_changes(src->data, src->size,
+                                  dst->data, dst->size,
+                                  delta_limit,
+                                  &src_copied, &literal_added))
                return 0;
-       }
-       free(delta);
 
        /* Extent of damage */
        if (src->size + literal_added < src_copied)

diff --git a/diffcore.h b/diffcore.h
index 12cd816..dba4f17 100644 (file)
--- a/diffcore.h
+++ b/diffcore.h
@@ -101,4 +101,10 @@ void diff_debug_queue(const char *, struct diff_queue_struct *);
 #define diff_debug_queue(a,b) do {} while(0)
 #endif
 
+extern int diffcore_count_changes(void *src, unsigned long src_size,
+                                 void *dst, unsigned long dst_size,
+                                 unsigned long delta_limit,
+                                 unsigned long *src_copied,
+                                 unsigned long *literal_added);
+
 #endif