Migrate code to git_filter_blob_contents.

Also removes the unnecessary check for filter 
length, since git_filters_apply does the right 
thing when there are none, and it's more efficient
than this.

src/checkout.c

@@ -32,49 +32,12 @@ typedef struct tree_walk_data
 } tree_walk_data;
 
 
-static int unfiltered_blob_contents(git_buf *out, git_repository *repo, const git_oid *blob_id)
-{
-	int retcode = GIT_ERROR;
-	git_blob *blob;
-
-	if (!(retcode = git_blob_lookup(&blob, repo, blob_id)))
-		retcode = git_blob__getbuf(out, blob);
-
-	return retcode;
-}
-
-static int filtered_blob_contents(git_buf *out, git_repository *repo, const git_oid *oid, const char *path)
-{
-	int retcode = GIT_ERROR;
-
-	git_buf unfiltered = GIT_BUF_INIT;
-	if (!unfiltered_blob_contents(&unfiltered, repo, oid)) {
-		git_vector filters = GIT_VECTOR_INIT;
-		int filter_count = git_filters_load(&filters, repo,
-														path, GIT_FILTER_TO_WORKTREE);
-		if (filter_count >= 0) {
-			git_buf_clear(out);
-			if (!filter_count) {
-				git_buf_put(out, git_buf_cstr(&unfiltered), git_buf_len(&unfiltered));
-				retcode = 0;
-			} else {
-				retcode = git_filters_apply(out, &unfiltered, &filters);
-			}
-		}
-
-		git_filters_free(&filters);
-	}
-
-	git_buf_free(&unfiltered);
-	return retcode;
-}
-
 static int blob_contents_to_file(git_repository *repo, git_buf *fnbuf, const git_oid *id, int mode)
 {
 	int retcode = GIT_ERROR;
 
 	git_buf filteredcontents = GIT_BUF_INIT;
-	if (!filtered_blob_contents(&filteredcontents, repo, id, git_buf_cstr(fnbuf))) {
+	if (!git_filter_blob_contents(&filteredcontents, repo, id, git_buf_cstr(fnbuf))) {
 		int fd = git_futils_creat_withpath(git_buf_cstr(fnbuf),
 													  GIT_DIR_MODE, mode);
 		if (fd >= 0) {

src/filter.c

@@ -11,6 +11,7 @@
 #include "filter.h"
 #include "repository.h"
 #include "git2/config.h"
+#include "blob.h"
 
 /* Tweaked from Core Git. I wonder what we could use this for... */
 void git_text_gather_stats(git_text_stats *stats, const git_buf *text)
@@ -163,3 +164,35 @@ int git_filters_apply(git_buf *dest, git_buf *source, git_vector *filters)
 
 	return 0;
 }
+
+static int unfiltered_blob_contents(git_buf *out, git_repository *repo, const git_oid *blob_id)
+{
+	int retcode = GIT_ERROR;
+	git_blob *blob;
+
+	if (!(retcode = git_blob_lookup(&blob, repo, blob_id)))
+		retcode = git_blob__getbuf(out, blob);
+
+	return retcode;
+}
+
+int git_filter_blob_contents(git_buf *out, git_repository *repo, const git_oid *oid, const char *path)
+{
+	int retcode = GIT_ERROR;
+
+	git_buf unfiltered = GIT_BUF_INIT;
+	if (!unfiltered_blob_contents(&unfiltered, repo, oid)) {
+		git_vector filters = GIT_VECTOR_INIT;
+		if (git_filters_load(&filters,
+									repo, path, GIT_FILTER_TO_WORKTREE) >= 0) {
+			git_buf_clear(out);
+			retcode = git_filters_apply(out, &unfiltered, &filters);
+		}
+
+		git_filters_free(&filters);
+	}
+
+	git_buf_free(&unfiltered);
+	return retcode;
+}
+

src/filter.h

@@ -119,4 +119,16 @@ extern void git_text_gather_stats(git_text_stats *stats, const git_buf *text);
  */
 extern int git_text_is_binary(git_text_stats *stats);
 
+
+/**
+ * Get the content of a blob after all filters have been run.
+ *
+ * @param out buffer to receive the contents
+ * @param repo repository containing the blob
+ * @param oid object id for the blob
+ * @param path path to the blob's output file, relative to the workdir root
+ * @return 0 on success, an error code otherwise
+ */
+extern int git_filter_blob_contents(git_buf *out, git_repository *repo, const git_oid *oid, const char *path);
+
 #endif