Add hunk/file headers to git_diff_patch_size

This allows git_diff_patch_size to account for hunk headers and
file headers in the returned size.  This required some refactoring
of the code that is used to print file headers so that it could be
invoked by the git_diff_patch_size API.

Also this increases the test coverage and fixes an off-by-one bug
in the size calculation when newline changes happen at the end of
the file.

1 files changed, 42 insertions, 37 deletions

diff --git a/src/diff_print.c b/src/diff_print.c
index 0de548813..cdb813176 100644
--- a/src/diff_print.c
+++ b/src/diff_print.c
@@ -198,13 +198,13 @@ int git_diff_print_raw(
 	return error;
 }
 
-static int diff_print_oid_range(diff_print_info *pi, const git_diff_delta *delta)
+static int diff_print_oid_range(
+	git_buf *out, const git_diff_delta *delta, int oid_strlen)
 {
-	git_buf *out = pi->buf;
 	char start_oid[GIT_OID_HEXSZ+1], end_oid[GIT_OID_HEXSZ+1];
 
-	git_oid_tostr(start_oid, pi->oid_strlen, &delta->old_file.oid);
-	git_oid_tostr(end_oid, pi->oid_strlen, &delta->new_file.oid);
+	git_oid_tostr(start_oid, oid_strlen, &delta->old_file.oid);
+	git_oid_tostr(end_oid, oid_strlen, &delta->new_file.oid);
 
 	/* TODO: Match git diff more closely */
 	if (delta->old_file.mode == delta->new_file.mode) {
@@ -228,35 +228,29 @@ static int diff_print_oid_range(diff_print_info *pi, const git_diff_delta *delta
 	return 0;
 }
 
-static int diff_print_patch_file(
-	const git_diff_delta *delta, float progress, void *data)
+int git_diff_delta__format_file_header(
+	git_buf *out,
+	const git_diff_delta *delta,
+	const char *oldpfx,
+	const char *newpfx,
+	int oid_strlen)
 {
-	diff_print_info *pi = data;
-	const char *oldpfx = pi->diff ? pi->diff->opts.old_prefix : NULL;
 	const char *oldpath = delta->old_file.path;
-	const char *newpfx = pi->diff ? pi->diff->opts.new_prefix : NULL;
 	const char *newpath = delta->new_file.path;
-	uint32_t opts_flags = pi->diff ? pi->diff->opts.flags : GIT_DIFF_NORMAL;
-
-	GIT_UNUSED(progress);
-
-	if (S_ISDIR(delta->new_file.mode) ||
-		delta->status == GIT_DELTA_UNMODIFIED ||
-		delta->status == GIT_DELTA_IGNORED ||
-		(delta->status == GIT_DELTA_UNTRACKED &&
-		 (opts_flags & GIT_DIFF_INCLUDE_UNTRACKED_CONTENT) == 0))
-		return 0;
 
 	if (!oldpfx)
 		oldpfx = DIFF_OLD_PREFIX_DEFAULT;
 	if (!newpfx)
 		newpfx = DIFF_NEW_PREFIX_DEFAULT;
+	if (!oid_strlen)
+		oid_strlen = GIT_ABBREV_DEFAULT + 1;
 
-	git_buf_clear(pi->buf);
-	git_buf_printf(pi->buf, "diff --git %s%s %s%s\n",
-		oldpfx, delta->old_file.path, newpfx, delta->new_file.path);
+	git_buf_clear(out);
+
+	git_buf_printf(out, "diff --git %s%s %s%s\n",
+		oldpfx, oldpath, newpfx, newpath);
 
-	if (diff_print_oid_range(pi, delta) < 0)
+	if (diff_print_oid_range(out, delta, oid_strlen) < 0)
 		return -1;
 
 	if (git_oid_iszero(&delta->old_file.oid)) {
@@ -269,28 +263,39 @@ static int diff_print_patch_file(
 	}
 
 	if ((delta->flags & GIT_DIFF_FLAG_BINARY) == 0) {
-		git_buf_printf(pi->buf, "--- %s%s\n", oldpfx, oldpath);
-		git_buf_printf(pi->buf, "+++ %s%s\n", newpfx, newpath);
+		git_buf_printf(out, "--- %s%s\n", oldpfx, oldpath);
+		git_buf_printf(out, "+++ %s%s\n", newpfx, newpath);
+	} else {
+		git_buf_printf(
+			out, "Binary files %s%s and %s%s differ\n",
+			oldpfx, oldpath, newpfx, newpath);
 	}
 
-	if (git_buf_oom(pi->buf))
-		return -1;
+	return git_buf_oom(out) ? -1 : 0;
+}
 
-	if (pi->print_cb(delta, NULL, GIT_DIFF_LINE_FILE_HDR,
-			git_buf_cstr(pi->buf), git_buf_len(pi->buf), pi->payload))
-		return callback_error();
+static int diff_print_patch_file(
+	const git_diff_delta *delta, float progress, void *data)
+{
+	diff_print_info *pi = data;
+	const char *oldpfx = pi->diff ? pi->diff->opts.old_prefix : NULL;
+	const char *newpfx = pi->diff ? pi->diff->opts.new_prefix : NULL;
+	uint32_t opts_flags = pi->diff ? pi->diff->opts.flags : GIT_DIFF_NORMAL;
 
-	if ((delta->flags & GIT_DIFF_FLAG_BINARY) == 0)
+	GIT_UNUSED(progress);
+
+	if (S_ISDIR(delta->new_file.mode) ||
+		delta->status == GIT_DELTA_UNMODIFIED ||
+		delta->status == GIT_DELTA_IGNORED ||
+		(delta->status == GIT_DELTA_UNTRACKED &&
+		 (opts_flags & GIT_DIFF_INCLUDE_UNTRACKED_CONTENT) == 0))
 		return 0;
 
-	git_buf_clear(pi->buf);
-	git_buf_printf(
-		pi->buf, "Binary files %s%s and %s%s differ\n",
-		oldpfx, oldpath, newpfx, newpath);
-	if (git_buf_oom(pi->buf))
+	if (git_diff_delta__format_file_header(
+			pi->buf, delta, oldpfx, newpfx, pi->oid_strlen) < 0)
 		return -1;
 
-	if (pi->print_cb(delta, NULL, GIT_DIFF_LINE_BINARY,
+	if (pi->print_cb(delta, NULL, GIT_DIFF_LINE_FILE_HDR,
 			git_buf_cstr(pi->buf), git_buf_len(pi->buf), pi->payload))
 		return callback_error();