Commit Diff


commit - f579bf773398809ee97341a20c91eadd918bc1ad
commit + 40fa9110668d1077088748f2be2bf9d5d9813b86
blob - /dev/null
blob + ee242a032fca32feed0692199a8e8ff1a8a4a2dd (mode 644)
--- /dev/null
+++ test/expect019.diff
@@ -0,0 +1,204 @@
+--- test019.left.txt
++++ test019.right.txt
+@@ -40,8 +40,23 @@
+ #include "got_lib_object.h"
+ 
+ static const struct got_error *
+-diff_blobs(struct got_diffreg_result **resultp,
+-struct got_blob_object *blob1, struct got_blob_object *blob2,
++add_line_offset(off_t **line_offsets, size_t *nlines, off_t off)
++{
++	off_t *p;
++
++	p = reallocarray(*line_offsets, *nlines + 1, sizeof(off_t));
++	if (p == NULL)
++		return got_error_from_errno("reallocarray");
++	*line_offsets = p;
++	(*line_offsets)[*nlines] = off;
++	(*nlines)++;
++	return NULL;
++}
++
++static const struct got_error *
++diff_blobs(off_t **line_offsets, size_t *nlines,
++    struct got_diffreg_result **resultp, struct got_blob_object *blob1,
++    struct got_blob_object *blob2,
+     const char *label1, const char *label2, mode_t mode1, mode_t mode2,
+     int diff_context, int ignore_whitespace, FILE *outfile)
+ {
+@@ -52,7 +67,12 @@
+ 	char *idstr1 = NULL, *idstr2 = NULL;
+ 	size_t size1, size2;
+ 	struct got_diffreg_result *result;
++	off_t outoff = 0;
++	int n;
+ 
++	if (line_offsets && *line_offsets && *nlines > 0)
++		outoff = (*line_offsets)[*nlines - 1];
++
+ 	if (resultp)
+ 		*resultp = NULL;
+ 
+@@ -116,10 +136,32 @@
+ 				goto done;
+ 			}
+ 		}
+-		fprintf(outfile, "blob - %s%s\n", idstr1,
++		n = fprintf(outfile, "blob - %s%s\n", idstr1,
+ 		    modestr1 ? modestr1 : "");
+-		fprintf(outfile, "blob + %s%s\n", idstr2,
++		if (n < 0) {
++			err = got_error_from_errno("fprintf");
++			goto done;
++		}
++		outoff += n;
++		if (line_offsets) {
++			err = add_line_offset(line_offsets, nlines, outoff);
++			if (err)
++				goto done;
++		}
++
++		n = fprintf(outfile, "blob + %s%s\n", idstr2,
+ 		    modestr2 ? modestr2 : "");
++		if (n < 0) {
++			err = got_error_from_errno("fprintf");
++			goto done;
++		}
++		outoff += n;
++		if (line_offsets) {
++			err = add_line_offset(line_offsets, nlines, outoff);
++			if (err)
++				goto done;
++		}
++
+ 		free(modestr1);
+ 		free(modestr2);
+ 	}
+@@ -129,7 +171,7 @@
+ 		goto done;
+ 
+ 	if (outfile) {
+-		err = got_diffreg_output(NULL, NULL, result, f1, f2,
++		err = got_diffreg_output(line_offsets, nlines, result, f1, f2,
+ 		    label1 ? label1 : idstr1,
+ 		    label2 ? label2 : idstr2,
+ 		    GOT_DIFF_OUTPUT_UNIDIFF, diff_context, outfile);
+@@ -158,21 +200,21 @@
+     struct got_object_id *id2, const char *label1, const char *label2,
+     mode_t mode1, mode_t mode2, struct got_repository *repo)
+ {
+-	const struct got_error *err;
+ 	struct got_diff_blob_output_unidiff_arg *a = arg;
+ 
+-	err = diff_blobs(NULL, blob1, blob2, label1, label2, mode1, mode2,
+-	    a->diff_context, a->ignore_whitespace, a->outfile);
+-	return err;
++	return diff_blobs(&a->line_offsets, &a->nlines, NULL,
++	    blob1, blob2, label1, label2, mode1, mode2, a->diff_context,
++	    a->ignore_whitespace, a->outfile);
+ }
+ 
+ const struct got_error *
+-got_diff_blob(struct got_blob_object *blob1, struct got_blob_object *blob2,
++got_diff_blob(off_t **line_offsets, size_t *nlines,
++    struct got_blob_object *blob1, struct got_blob_object *blob2,
+     const char *label1, const char *label2, int diff_context,
+     int ignore_whitespace, FILE *outfile)
+ {
+-	return diff_blobs(NULL, blob1, blob2, label1, label2, 0, 0, diff_context,
+-	    ignore_whitespace, outfile);
++	return diff_blobs(line_offsets, nlines, NULL, blob1, blob2,
++	    label1, label2, 0, 0, diff_context, ignore_whitespace, outfile);
+ }
+ 
+ static const struct got_error *
+@@ -259,7 +301,8 @@
+ {
+ 	const struct got_error *err = NULL;
+ 
+-	err = diff_blobs(result, blob1, blob2, NULL, NULL, 0, 0, 3, 0, NULL);
++	err = diff_blobs(NULL, NULL, result, blob1, blob2,
++	    NULL, NULL, 0, 0, 3, 0, NULL);
+ 	if (err) {
+ 		got_diffreg_result_free(*result);
+ 		*result = NULL;
+@@ -702,7 +745,8 @@
+ }
+ 
+ const struct got_error *
+-got_diff_objects_as_blobs(struct got_object_id *id1, struct got_object_id *id2,
++got_diff_objects_as_blobs(off_t **line_offsets, size_t *nlines,
++    struct got_object_id *id1, struct got_object_id *id2,
+     const char *label1, const char *label2, int diff_context,
+     int ignore_whitespace, struct got_repository *repo, FILE *outfile)
+ {
+@@ -722,8 +766,8 @@
+ 		if (err)
+ 			goto done;
+ 	}
+-	err = got_diff_blob(blob1, blob2, label1, label2, diff_context,
+-	    ignore_whitespace, outfile);
++	err = got_diff_blob(line_offsets, nlines, blob1, blob2,
++	    label1, label2, diff_context, ignore_whitespace, outfile);
+ done:
+ 	if (blob1)
+ 		got_object_blob_close(blob1);
+@@ -733,13 +777,15 @@
+ }
+ 
+ const struct got_error *
+-got_diff_objects_as_trees(struct got_object_id *id1, struct got_object_id *id2,
++got_diff_objects_as_trees(off_t **line_offsets, size_t *nlines,
++    struct got_object_id *id1, struct got_object_id *id2,
+     char *label1, char *label2, int diff_context, int ignore_whitespace,
+     struct got_repository *repo, FILE *outfile)
+ {
+ 	const struct got_error *err;
+ 	struct got_tree_object *tree1 = NULL, *tree2 = NULL;
+ 	struct got_diff_blob_output_unidiff_arg arg;
++	int want_lineoffsets = (line_offsets != NULL && *line_offsets != NULL);
+ 
+ 	if (id1 == NULL && id2 == NULL)
+ 		return got_error(GOT_ERR_NO_OBJ);
+@@ -757,8 +803,20 @@
+ 	arg.diff_context = diff_context;
+ 	arg.ignore_whitespace = ignore_whitespace;
+ 	arg.outfile = outfile;
++	if (want_lineoffsets) {
++		arg.line_offsets = *line_offsets;
++		arg.nlines = *nlines;
++	} else {
++		arg.line_offsets = NULL;
++		arg.nlines = 0;
++	}
+ 	err = got_diff_tree(tree1, tree2, label1, label2, repo,
+ 	    got_diff_blob_output_unidiff, &arg, 1);
++
++	if (want_lineoffsets) {
++		*line_offsets = arg.line_offsets; /* was likely re-allocated */
++		*nlines = arg.nlines;
++	}
+ done:
+ 	if (tree1)
+ 		got_object_tree_close(tree1);
+@@ -768,8 +826,9 @@
+ }
+ 
+ const struct got_error *
+-got_diff_objects_as_commits(struct got_object_id *id1,
+-    struct got_object_id *id2, int diff_context, int ignore_whitespace,
++got_diff_objects_as_commits(off_t **line_offsets, size_t *nlines,
++    struct got_object_id *id1, struct got_object_id *id2,
++    int diff_context, int ignore_whitespace,
+     struct got_repository *repo, FILE *outfile)
+ {
+ 	const struct got_error *err;
+@@ -788,7 +847,7 @@
+ 	if (err)
+ 		goto done;
+ 
+-	err = got_diff_objects_as_trees(
++	err = got_diff_objects_as_trees(line_offsets, nlines,
+ 	    commit1 ? got_object_commit_get_tree_id(commit1) : NULL,
+ 	    got_object_commit_get_tree_id(commit2), "", "", diff_context,
+ 	    ignore_whitespace, repo, outfile);
blob - /dev/null
blob + ac4b5ececbb399b94f65fcb8c812c9394598fcc6 (mode 644)
--- /dev/null
+++ test/test019.left.txt
@@ -0,0 +1,845 @@
+/*
+ * Copyright (c) 2017 Stefan Sperling <stsp@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/queue.h>
+#include <sys/stat.h>
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <sha1.h>
+#include <zlib.h>
+
+#include "got_object.h"
+#include "got_repository.h"
+#include "got_error.h"
+#include "got_diff.h"
+#include "got_opentemp.h"
+#include "got_path.h"
+#include "got_cancel.h"
+#include "got_worktree.h"
+
+#include "got_lib_diff.h"
+#include "got_lib_delta.h"
+#include "got_lib_inflate.h"
+#include "got_lib_object.h"
+
+static const struct got_error *
+diff_blobs(struct got_diffreg_result **resultp,
+struct got_blob_object *blob1, struct got_blob_object *blob2,
+    const char *label1, const char *label2, mode_t mode1, mode_t mode2,
+    int diff_context, int ignore_whitespace, FILE *outfile)
+{
+	const struct got_error *err = NULL, *free_err;
+	FILE *f1 = NULL, *f2 = NULL;
+	char hex1[SHA1_DIGEST_STRING_LENGTH];
+	char hex2[SHA1_DIGEST_STRING_LENGTH];
+	char *idstr1 = NULL, *idstr2 = NULL;
+	size_t size1, size2;
+	struct got_diffreg_result *result;
+
+	if (resultp)
+		*resultp = NULL;
+
+	if (blob1) {
+		f1 = got_opentemp();
+		if (f1 == NULL)
+			return got_error_from_errno("got_opentemp");
+	}
+
+	if (blob2) {
+		f2 = got_opentemp();
+		if (f2 == NULL) {
+			err = got_error_from_errno("got_opentemp");
+			fclose(f1);
+			return err;
+		}
+	}
+
+	size1 = 0;
+	if (blob1) {
+		idstr1 = got_object_blob_id_str(blob1, hex1, sizeof(hex1));
+		err = got_object_blob_dump_to_file(&size1, NULL, NULL, f1,
+		    blob1);
+		if (err)
+			goto done;
+	} else
+		idstr1 = "/dev/null";
+
+	size2 = 0;
+	if (blob2) {
+		idstr2 = got_object_blob_id_str(blob2, hex2, sizeof(hex2));
+		err = got_object_blob_dump_to_file(&size2, NULL, NULL, f2,
+		    blob2);
+		if (err)
+			goto done;
+	} else
+		idstr2 = "/dev/null";
+
+	if (outfile) {
+		char *modestr1 = NULL, *modestr2 = NULL;
+		int modebits;
+		if (mode1 && mode1 != mode2) {
+			if (S_ISLNK(mode1))
+				modebits = S_IFLNK;
+			else
+				modebits = (S_IRWXU | S_IRWXG | S_IRWXO);
+			if (asprintf(&modestr1, " (mode %o)",
+			    mode1 & modebits) == -1) {
+				err = got_error_from_errno("asprintf");
+				goto done;
+			}
+		}
+		if (mode2 && mode1 != mode2) {
+			if (S_ISLNK(mode2))
+				modebits = S_IFLNK;
+			else
+				modebits = (S_IRWXU | S_IRWXG | S_IRWXO);
+			if (asprintf(&modestr2, " (mode %o)",
+			    mode2 & modebits) == -1) {
+				err = got_error_from_errno("asprintf");
+				goto done;
+			}
+		}
+		fprintf(outfile, "blob - %s%s\n", idstr1,
+		    modestr1 ? modestr1 : "");
+		fprintf(outfile, "blob + %s%s\n", idstr2,
+		    modestr2 ? modestr2 : "");
+		free(modestr1);
+		free(modestr2);
+	}
+	err = got_diffreg(&result, f1, f2, GOT_DIFF_ALGORITHM_MYERS,
+	    ignore_whitespace);
+	if (err)
+		goto done;
+
+	if (outfile) {
+		err = got_diffreg_output(NULL, NULL, result, f1, f2,
+		    label1 ? label1 : idstr1,
+		    label2 ? label2 : idstr2,
+		    GOT_DIFF_OUTPUT_UNIDIFF, diff_context, outfile);
+		if (err)
+			goto done;
+	}
+
+	if (resultp && err == NULL)
+		*resultp = result;
+	else {
+		free_err = got_diffreg_result_free(result);
+		if (free_err && err == NULL)
+			err = free_err;
+	}
+done:
+	if (f1 && fclose(f1) != 0 && err == NULL)
+		err = got_error_from_errno("fclose");
+	if (f2 && fclose(f2) != 0 && err == NULL)
+		err = got_error_from_errno("fclose");
+	return err;
+}
+
+const struct got_error *
+got_diff_blob_output_unidiff(void *arg, struct got_blob_object *blob1,
+    struct got_blob_object *blob2, struct got_object_id *id1,
+    struct got_object_id *id2, const char *label1, const char *label2,
+    mode_t mode1, mode_t mode2, struct got_repository *repo)
+{
+	const struct got_error *err;
+	struct got_diff_blob_output_unidiff_arg *a = arg;
+
+	err = diff_blobs(NULL, blob1, blob2, label1, label2, mode1, mode2,
+	    a->diff_context, a->ignore_whitespace, a->outfile);
+	return err;
+}
+
+const struct got_error *
+got_diff_blob(struct got_blob_object *blob1, struct got_blob_object *blob2,
+    const char *label1, const char *label2, int diff_context,
+    int ignore_whitespace, FILE *outfile)
+{
+	return diff_blobs(NULL, blob1, blob2, label1, label2, 0, 0, diff_context,
+	    ignore_whitespace, outfile);
+}
+
+static const struct got_error *
+diff_blob_file(struct got_diffreg_result **resultp,
+    struct got_blob_object *blob1, const char *label1, FILE *f2, size_t size2,
+    const char *label2, int diff_context, int ignore_whitespace, FILE *outfile)
+{
+	const struct got_error *err = NULL, *free_err;
+	FILE *f1 = NULL;
+	char hex1[SHA1_DIGEST_STRING_LENGTH];
+	char *idstr1 = NULL;
+	size_t size1;
+	struct got_diffreg_result *result = NULL;
+
+	if (resultp)
+		*resultp = NULL;
+
+	size1 = 0;
+	if (blob1) {
+		f1 = got_opentemp();
+		if (f1 == NULL)
+			return got_error_from_errno("got_opentemp");
+		idstr1 = got_object_blob_id_str(blob1, hex1, sizeof(hex1));
+		err = got_object_blob_dump_to_file(&size1, NULL, NULL, f1,
+		    blob1);
+		if (err)
+			goto done;
+	} else {
+		idstr1 = "/dev/null";
+	}
+
+	if (outfile) {
+		fprintf(outfile, "blob - %s\n", label1 ? label1 : idstr1);
+		fprintf(outfile, "file + %s\n",
+		    f2 == NULL ? "/dev/null" : label2);
+	}
+
+	err = got_diffreg(&result, f1, f2, GOT_DIFF_ALGORITHM_MYERS, 
+	    ignore_whitespace);
+	if (err)
+		goto done;
+
+	if (outfile) {
+		err = got_diffreg_output(NULL, NULL, result, f1, f2,
+		    label2, label2, GOT_DIFF_OUTPUT_UNIDIFF, diff_context,
+		    outfile);
+		if (err)
+			goto done;
+	}
+
+	if (resultp && err == NULL)
+		*resultp = result;
+	else if (result) {
+		free_err = got_diffreg_result_free(result);
+		if (free_err && err == NULL)
+			err = free_err;
+	}
+done:
+	if (f1 && fclose(f1) != 0 && err == NULL)
+		err = got_error_from_errno("fclose");
+	return err;
+}
+
+const struct got_error *
+got_diff_blob_file(struct got_blob_object *blob1, const char *label1,
+    FILE *f2, size_t size2, const char *label2, int diff_context,
+    int ignore_whitespace, FILE *outfile)
+{
+	return diff_blob_file(NULL, blob1, label1, f2, size2, label2,
+	    diff_context, ignore_whitespace, outfile);
+}
+
+const struct got_error *
+got_diff_blob_file_lines_changed(struct got_diffreg_result **result,
+    struct got_blob_object *blob1, FILE *f2, size_t size2)
+{
+	return diff_blob_file(result, blob1, NULL, f2, size2, NULL,
+	    0, 0, NULL);
+}
+
+const struct got_error *
+got_diff_blob_lines_changed(struct got_diffreg_result **result,
+    struct got_blob_object *blob1, struct got_blob_object *blob2)
+{
+	const struct got_error *err = NULL;
+
+	err = diff_blobs(result, blob1, blob2, NULL, NULL, 0, 0, 3, 0, NULL);
+	if (err) {
+		got_diffreg_result_free(*result);
+		*result = NULL;
+	}
+	return err;
+}
+
+static const struct got_error *
+diff_added_blob(struct got_object_id *id, const char *label, mode_t mode,
+    struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg)
+{
+	const struct got_error *err;
+	struct got_blob_object  *blob = NULL;
+	struct got_object *obj = NULL;
+
+	err = got_object_open(&obj, repo, id);
+	if (err)
+		return err;
+
+	err = got_object_blob_open(&blob, repo, obj, 8192);
+	if (err)
+		goto done;
+	err = cb(cb_arg, NULL, blob, NULL, id, NULL, label, 0, mode, repo);
+done:
+	got_object_close(obj);
+	if (blob)
+		got_object_blob_close(blob);
+	return err;
+}
+
+static const struct got_error *
+diff_modified_blob(struct got_object_id *id1, struct got_object_id *id2,
+    const char *label1, const char *label2, mode_t mode1, mode_t mode2,
+    struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg)
+{
+	const struct got_error *err;
+	struct got_object *obj1 = NULL;
+	struct got_object *obj2 = NULL;
+	struct got_blob_object *blob1 = NULL;
+	struct got_blob_object *blob2 = NULL;
+
+	err = got_object_open(&obj1, repo, id1);
+	if (err)
+		return err;
+	if (obj1->type != GOT_OBJ_TYPE_BLOB) {
+		err = got_error(GOT_ERR_OBJ_TYPE);
+		goto done;
+	}
+
+	err = got_object_open(&obj2, repo, id2);
+	if (err)
+		goto done;
+	if (obj2->type != GOT_OBJ_TYPE_BLOB) {
+		err = got_error(GOT_ERR_BAD_OBJ_DATA);
+		goto done;
+	}
+
+	err = got_object_blob_open(&blob1, repo, obj1, 8192);
+	if (err)
+		goto done;
+
+	err = got_object_blob_open(&blob2, repo, obj2, 8192);
+	if (err)
+		goto done;
+
+	err = cb(cb_arg, blob1, blob2, id1, id2, label1, label2, mode1, mode2,
+	    repo);
+done:
+	if (obj1)
+		got_object_close(obj1);
+	if (obj2)
+		got_object_close(obj2);
+	if (blob1)
+		got_object_blob_close(blob1);
+	if (blob2)
+		got_object_blob_close(blob2);
+	return err;
+}
+
+static const struct got_error *
+diff_deleted_blob(struct got_object_id *id, const char *label, mode_t mode,
+    struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg)
+{
+	const struct got_error *err;
+	struct got_blob_object  *blob = NULL;
+	struct got_object *obj = NULL;
+
+	err = got_object_open(&obj, repo, id);
+	if (err)
+		return err;
+
+	err = got_object_blob_open(&blob, repo, obj, 8192);
+	if (err)
+		goto done;
+	err = cb(cb_arg, blob, NULL, id, NULL, label, NULL, mode, 0, repo);
+done:
+	got_object_close(obj);
+	if (blob)
+		got_object_blob_close(blob);
+	return err;
+}
+
+static const struct got_error *
+diff_added_tree(struct got_object_id *id, const char *label,
+    struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
+    int diff_content)
+{
+	const struct got_error *err = NULL;
+	struct got_object *treeobj = NULL;
+	struct got_tree_object *tree = NULL;
+
+	err = got_object_open(&treeobj, repo, id);
+	if (err)
+		goto done;
+
+	if (treeobj->type != GOT_OBJ_TYPE_TREE) {
+		err = got_error(GOT_ERR_OBJ_TYPE);
+		goto done;
+	}
+
+	err = got_object_tree_open(&tree, repo, treeobj);
+	if (err)
+		goto done;
+
+	err = got_diff_tree(NULL, tree, NULL, label, repo, cb, cb_arg,
+	    diff_content);
+done:
+	if (tree)
+		got_object_tree_close(tree);
+	if (treeobj)
+		got_object_close(treeobj);
+	return err;
+}
+
+static const struct got_error *
+diff_modified_tree(struct got_object_id *id1, struct got_object_id *id2,
+    const char *label1, const char *label2, struct got_repository *repo,
+    got_diff_blob_cb cb, void *cb_arg, int diff_content)
+{
+	const struct got_error *err;
+	struct got_object *treeobj1 = NULL;
+	struct got_object *treeobj2 = NULL;
+	struct got_tree_object *tree1 = NULL;
+	struct got_tree_object *tree2 = NULL;
+
+	err = got_object_open(&treeobj1, repo, id1);
+	if (err)
+		goto done;
+
+	if (treeobj1->type != GOT_OBJ_TYPE_TREE) {
+		err = got_error(GOT_ERR_OBJ_TYPE);
+		goto done;
+	}
+
+	err = got_object_open(&treeobj2, repo, id2);
+	if (err)
+		goto done;
+
+	if (treeobj2->type != GOT_OBJ_TYPE_TREE) {
+		err = got_error(GOT_ERR_OBJ_TYPE);
+		goto done;
+	}
+
+	err = got_object_tree_open(&tree1, repo, treeobj1);
+	if (err)
+		goto done;
+
+	err = got_object_tree_open(&tree2, repo, treeobj2);
+	if (err)
+		goto done;
+
+	err = got_diff_tree(tree1, tree2, label1, label2, repo, cb, cb_arg,
+	    diff_content);
+
+done:
+	if (tree1)
+		got_object_tree_close(tree1);
+	if (tree2)
+		got_object_tree_close(tree2);
+	if (treeobj1)
+		got_object_close(treeobj1);
+	if (treeobj2)
+		got_object_close(treeobj2);
+	return err;
+}
+
+static const struct got_error *
+diff_deleted_tree(struct got_object_id *id, const char *label,
+    struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
+    int diff_content)
+{
+	const struct got_error *err;
+	struct got_object *treeobj = NULL;
+	struct got_tree_object *tree = NULL;
+
+	err = got_object_open(&treeobj, repo, id);
+	if (err)
+		goto done;
+
+	if (treeobj->type != GOT_OBJ_TYPE_TREE) {
+		err = got_error(GOT_ERR_OBJ_TYPE);
+		goto done;
+	}
+
+	err = got_object_tree_open(&tree, repo, treeobj);
+	if (err)
+		goto done;
+
+	err = got_diff_tree(tree, NULL, label, NULL, repo, cb, cb_arg,
+	    diff_content);
+done:
+	if (tree)
+		got_object_tree_close(tree);
+	if (treeobj)
+		got_object_close(treeobj);
+	return err;
+}
+
+static const struct got_error *
+diff_kind_mismatch(struct got_object_id *id1, struct got_object_id *id2,
+    const char *label1, const char *label2, struct got_repository *repo,
+    got_diff_blob_cb cb, void *cb_arg)
+{
+	/* XXX TODO */
+	return NULL;
+}
+
+static const struct got_error *
+diff_entry_old_new(struct got_tree_entry *te1,
+    struct got_tree_entry *te2, const char *label1, const char *label2,
+    struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
+    int diff_content)
+{
+	const struct got_error *err = NULL;
+	int id_match;
+
+	if (got_object_tree_entry_is_submodule(te1))
+		return NULL;
+
+	if (te2 == NULL) {
+		if (S_ISDIR(te1->mode))
+			err = diff_deleted_tree(&te1->id, label1, repo,
+			    cb, cb_arg, diff_content);
+		else {
+			if (diff_content)
+				err = diff_deleted_blob(&te1->id, label1,
+				    te1->mode, repo, cb, cb_arg);
+			else
+				err = cb(cb_arg, NULL, NULL, &te1->id, NULL,
+				    label1, NULL, te1->mode, 0, repo);
+		}
+		return err;
+	} else if (got_object_tree_entry_is_submodule(te2))
+		return NULL;
+
+	id_match = (got_object_id_cmp(&te1->id, &te2->id) == 0);
+	if (S_ISDIR(te1->mode) && S_ISDIR(te2->mode)) {
+		if (!id_match)
+			return diff_modified_tree(&te1->id, &te2->id,
+			    label1, label2, repo, cb, cb_arg, diff_content);
+	} else if ((S_ISREG(te1->mode) || S_ISLNK(te1->mode)) &&
+	    (S_ISREG(te2->mode) || S_ISLNK(te2->mode))) {
+		if (!id_match ||
+		    ((te1->mode & (S_IFLNK | S_IXUSR))) !=
+		    (te2->mode & (S_IFLNK | S_IXUSR))) {
+			if (diff_content)
+				return diff_modified_blob(&te1->id, &te2->id,
+				    label1, label2, te1->mode, te2->mode,
+				    repo, cb, cb_arg);
+			else
+				return cb(cb_arg, NULL, NULL, &te1->id,
+				    &te2->id, label1, label2, te1->mode,
+				    te2->mode, repo);
+		}
+	}
+
+	if (id_match)
+		return NULL;
+
+	return diff_kind_mismatch(&te1->id, &te2->id, label1, label2, repo,
+	    cb, cb_arg);
+}
+
+static const struct got_error *
+diff_entry_new_old(struct got_tree_entry *te2,
+    struct got_tree_entry *te1, const char *label2,
+    struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
+    int diff_content)
+{
+	if (te1 != NULL) /* handled by diff_entry_old_new() */
+		return NULL;
+
+	if (got_object_tree_entry_is_submodule(te2))
+		return NULL;
+
+	if (S_ISDIR(te2->mode))
+		return diff_added_tree(&te2->id, label2, repo, cb, cb_arg,
+		    diff_content);
+
+	if (diff_content)
+		return diff_added_blob(&te2->id, label2, te2->mode, repo, cb,
+		    cb_arg);
+
+	return cb(cb_arg, NULL, NULL, NULL, &te2->id, NULL, label2, 0,
+	    te2->mode, repo);
+}
+
+const struct got_error *
+got_diff_tree_collect_changed_paths(void *arg, struct got_blob_object *blob1,
+    struct got_blob_object *blob2, struct got_object_id *id1,
+    struct got_object_id *id2, const char *label1, const char *label2,
+    mode_t mode1, mode_t mode2, struct got_repository *repo)
+{
+	const struct got_error *err = NULL;
+	struct got_pathlist_head *paths = arg;
+	struct got_diff_changed_path *change = NULL;
+	char *path = NULL;
+
+	path = strdup(label2 ? label2 : label1);
+	if (path == NULL)
+		return got_error_from_errno("malloc");
+
+	change = malloc(sizeof(*change));
+	if (change == NULL) {
+		err = got_error_from_errno("malloc");
+		goto done;
+	}
+
+	change->status = GOT_STATUS_NO_CHANGE;
+	if (id1 == NULL)
+		change->status = GOT_STATUS_ADD;
+	else if (id2 == NULL)
+		change->status = GOT_STATUS_DELETE;
+	else {
+		if (got_object_id_cmp(id1, id2) != 0)
+			change->status = GOT_STATUS_MODIFY;
+		else if (mode1 != mode2)
+			change->status = GOT_STATUS_MODE_CHANGE;
+	}
+
+	err = got_pathlist_insert(NULL, paths, path, change);
+done:
+	if (err) {
+		free(path);
+		free(change);
+	}
+	return err;
+}
+
+const struct got_error *
+got_diff_tree(struct got_tree_object *tree1, struct got_tree_object *tree2,
+    const char *label1, const char *label2, struct got_repository *repo,
+    got_diff_blob_cb cb, void *cb_arg, int diff_content)
+{
+	const struct got_error *err = NULL;
+	struct got_tree_entry *te1 = NULL;
+	struct got_tree_entry *te2 = NULL;
+	char *l1 = NULL, *l2 = NULL;
+	int tidx1 = 0, tidx2 = 0;
+
+	if (tree1) {
+		te1 = got_object_tree_get_entry(tree1, 0);
+		if (te1 && asprintf(&l1, "%s%s%s", label1, label1[0] ? "/" : "",
+		    te1->name) == -1)
+			return got_error_from_errno("asprintf");
+	}
+	if (tree2) {
+		te2 = got_object_tree_get_entry(tree2, 0);
+		if (te2 && asprintf(&l2, "%s%s%s", label2, label2[0] ? "/" : "",
+		    te2->name) == -1)
+			return got_error_from_errno("asprintf");
+	}
+
+	do {
+		if (te1) {
+			struct got_tree_entry *te = NULL;
+			if (tree2)
+				te = got_object_tree_find_entry(tree2,
+				    te1->name);
+			if (te) {
+				free(l2);
+				l2 = NULL;
+				if (te && asprintf(&l2, "%s%s%s", label2,
+				    label2[0] ? "/" : "", te->name) == -1)
+					return
+					    got_error_from_errno("asprintf");
+			}
+			err = diff_entry_old_new(te1, te, l1, l2, repo, cb,
+			    cb_arg, diff_content);
+			if (err)
+				break;
+		}
+
+		if (te2) {
+			struct got_tree_entry *te = NULL;
+			if (tree1)
+				te = got_object_tree_find_entry(tree1,
+				    te2->name);
+			free(l2);
+			if (te) {
+				if (asprintf(&l2, "%s%s%s", label2,
+				    label2[0] ? "/" : "", te->name) == -1)
+					return
+					    got_error_from_errno("asprintf");
+			} else {
+				if (asprintf(&l2, "%s%s%s", label2,
+				    label2[0] ? "/" : "", te2->name) == -1)
+					return
+					    got_error_from_errno("asprintf");
+			}
+			err = diff_entry_new_old(te2, te, l2, repo,
+			    cb, cb_arg, diff_content);
+			if (err)
+				break;
+		}
+
+		free(l1);
+		l1 = NULL;
+		if (te1) {
+			tidx1++;
+			te1 = got_object_tree_get_entry(tree1, tidx1);
+			if (te1 &&
+			    asprintf(&l1, "%s%s%s", label1,
+			    label1[0] ? "/" : "", te1->name) == -1)
+				return got_error_from_errno("asprintf");
+		}
+		free(l2);
+		l2 = NULL;
+		if (te2) {
+			tidx2++;
+			te2 = got_object_tree_get_entry(tree2, tidx2);
+			if (te2 &&
+			    asprintf(&l2, "%s%s%s", label2,
+			        label2[0] ? "/" : "", te2->name) == -1)
+				return got_error_from_errno("asprintf");
+		}
+	} while (te1 || te2);
+
+	return err;
+}
+
+const struct got_error *
+got_diff_objects_as_blobs(struct got_object_id *id1, struct got_object_id *id2,
+    const char *label1, const char *label2, int diff_context,
+    int ignore_whitespace, struct got_repository *repo, FILE *outfile)
+{
+	const struct got_error *err;
+	struct got_blob_object *blob1 = NULL, *blob2 = NULL;
+
+	if (id1 == NULL && id2 == NULL)
+		return got_error(GOT_ERR_NO_OBJ);
+
+	if (id1) {
+		err = got_object_open_as_blob(&blob1, repo, id1, 8192);
+		if (err)
+			goto done;
+	}
+	if (id2) {
+		err = got_object_open_as_blob(&blob2, repo, id2, 8192);
+		if (err)
+			goto done;
+	}
+	err = got_diff_blob(blob1, blob2, label1, label2, diff_context,
+	    ignore_whitespace, outfile);
+done:
+	if (blob1)
+		got_object_blob_close(blob1);
+	if (blob2)
+		got_object_blob_close(blob2);
+	return err;
+}
+
+const struct got_error *
+got_diff_objects_as_trees(struct got_object_id *id1, struct got_object_id *id2,
+    char *label1, char *label2, int diff_context, int ignore_whitespace,
+    struct got_repository *repo, FILE *outfile)
+{
+	const struct got_error *err;
+	struct got_tree_object *tree1 = NULL, *tree2 = NULL;
+	struct got_diff_blob_output_unidiff_arg arg;
+
+	if (id1 == NULL && id2 == NULL)
+		return got_error(GOT_ERR_NO_OBJ);
+
+	if (id1) {
+		err = got_object_open_as_tree(&tree1, repo, id1);
+		if (err)
+			goto done;
+	}
+	if (id2) {
+		err = got_object_open_as_tree(&tree2, repo, id2);
+		if (err)
+			goto done;
+	}
+	arg.diff_context = diff_context;
+	arg.ignore_whitespace = ignore_whitespace;
+	arg.outfile = outfile;
+	err = got_diff_tree(tree1, tree2, label1, label2, repo,
+	    got_diff_blob_output_unidiff, &arg, 1);
+done:
+	if (tree1)
+		got_object_tree_close(tree1);
+	if (tree2)
+		got_object_tree_close(tree2);
+	return err;
+}
+
+const struct got_error *
+got_diff_objects_as_commits(struct got_object_id *id1,
+    struct got_object_id *id2, int diff_context, int ignore_whitespace,
+    struct got_repository *repo, FILE *outfile)
+{
+	const struct got_error *err;
+	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
+
+	if (id2 == NULL)
+		return got_error(GOT_ERR_NO_OBJ);
+
+	if (id1) {
+		err = got_object_open_as_commit(&commit1, repo, id1);
+		if (err)
+			goto done;
+	}
+
+	err = got_object_open_as_commit(&commit2, repo, id2);
+	if (err)
+		goto done;
+
+	err = got_diff_objects_as_trees(
+	    commit1 ? got_object_commit_get_tree_id(commit1) : NULL,
+	    got_object_commit_get_tree_id(commit2), "", "", diff_context,
+	    ignore_whitespace, repo, outfile);
+done:
+	if (commit1)
+		got_object_commit_close(commit1);
+	if (commit2)
+		got_object_commit_close(commit2);
+	return err;
+}
+
+const struct got_error *
+got_diff_files(struct got_diffreg_result **resultp,
+    FILE *f1, const char *label1, FILE *f2, const char *label2,
+    int diff_context, int ignore_whitespace, FILE *outfile)
+{
+	const struct got_error *err = NULL;
+	struct got_diffreg_result *diffreg_result = NULL;
+
+	if (resultp)
+		*resultp = NULL;
+
+	if (outfile) {
+		fprintf(outfile, "file - %s\n",
+		    f1 == NULL ? "/dev/null" : label1);
+		fprintf(outfile, "file + %s\n",
+		    f2 == NULL ? "/dev/null" : label2);
+	}
+
+	err = got_diffreg(&diffreg_result, f1, f2, GOT_DIFF_ALGORITHM_MYERS,
+	    ignore_whitespace);
+	if (err)
+		goto done;
+
+	if (outfile) {
+		err = got_diffreg_output(NULL, NULL, diffreg_result,
+		    f1, f2, label1, label2, GOT_DIFF_OUTPUT_UNIDIFF,
+		    diff_context, outfile);
+		if (err)
+			goto done;
+	}
+
+done:
+	if (resultp && err == NULL)
+		*resultp = diffreg_result;
+	else if (diffreg_result) {
+		const struct got_error *free_err;
+		free_err = got_diffreg_result_free(diffreg_result);
+		if (free_err && err == NULL)
+			err = free_err;
+	}
+
+	return err;
+}
blob - /dev/null
blob + 69c2895af058f1f1b87c15df8761bcd9bdc726b2 (mode 644)
--- /dev/null
+++ test/test019.right.txt
@@ -0,0 +1,904 @@
+/*
+ * Copyright (c) 2017 Stefan Sperling <stsp@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/queue.h>
+#include <sys/stat.h>
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <sha1.h>
+#include <zlib.h>
+
+#include "got_object.h"
+#include "got_repository.h"
+#include "got_error.h"
+#include "got_diff.h"
+#include "got_opentemp.h"
+#include "got_path.h"
+#include "got_cancel.h"
+#include "got_worktree.h"
+
+#include "got_lib_diff.h"
+#include "got_lib_delta.h"
+#include "got_lib_inflate.h"
+#include "got_lib_object.h"
+
+static const struct got_error *
+add_line_offset(off_t **line_offsets, size_t *nlines, off_t off)
+{
+	off_t *p;
+
+	p = reallocarray(*line_offsets, *nlines + 1, sizeof(off_t));
+	if (p == NULL)
+		return got_error_from_errno("reallocarray");
+	*line_offsets = p;
+	(*line_offsets)[*nlines] = off;
+	(*nlines)++;
+	return NULL;
+}
+
+static const struct got_error *
+diff_blobs(off_t **line_offsets, size_t *nlines,
+    struct got_diffreg_result **resultp, struct got_blob_object *blob1,
+    struct got_blob_object *blob2,
+    const char *label1, const char *label2, mode_t mode1, mode_t mode2,
+    int diff_context, int ignore_whitespace, FILE *outfile)
+{
+	const struct got_error *err = NULL, *free_err;
+	FILE *f1 = NULL, *f2 = NULL;
+	char hex1[SHA1_DIGEST_STRING_LENGTH];
+	char hex2[SHA1_DIGEST_STRING_LENGTH];
+	char *idstr1 = NULL, *idstr2 = NULL;
+	size_t size1, size2;
+	struct got_diffreg_result *result;
+	off_t outoff = 0;
+	int n;
+
+	if (line_offsets && *line_offsets && *nlines > 0)
+		outoff = (*line_offsets)[*nlines - 1];
+
+	if (resultp)
+		*resultp = NULL;
+
+	if (blob1) {
+		f1 = got_opentemp();
+		if (f1 == NULL)
+			return got_error_from_errno("got_opentemp");
+	}
+
+	if (blob2) {
+		f2 = got_opentemp();
+		if (f2 == NULL) {
+			err = got_error_from_errno("got_opentemp");
+			fclose(f1);
+			return err;
+		}
+	}
+
+	size1 = 0;
+	if (blob1) {
+		idstr1 = got_object_blob_id_str(blob1, hex1, sizeof(hex1));
+		err = got_object_blob_dump_to_file(&size1, NULL, NULL, f1,
+		    blob1);
+		if (err)
+			goto done;
+	} else
+		idstr1 = "/dev/null";
+
+	size2 = 0;
+	if (blob2) {
+		idstr2 = got_object_blob_id_str(blob2, hex2, sizeof(hex2));
+		err = got_object_blob_dump_to_file(&size2, NULL, NULL, f2,
+		    blob2);
+		if (err)
+			goto done;
+	} else
+		idstr2 = "/dev/null";
+
+	if (outfile) {
+		char *modestr1 = NULL, *modestr2 = NULL;
+		int modebits;
+		if (mode1 && mode1 != mode2) {
+			if (S_ISLNK(mode1))
+				modebits = S_IFLNK;
+			else
+				modebits = (S_IRWXU | S_IRWXG | S_IRWXO);
+			if (asprintf(&modestr1, " (mode %o)",
+			    mode1 & modebits) == -1) {
+				err = got_error_from_errno("asprintf");
+				goto done;
+			}
+		}
+		if (mode2 && mode1 != mode2) {
+			if (S_ISLNK(mode2))
+				modebits = S_IFLNK;
+			else
+				modebits = (S_IRWXU | S_IRWXG | S_IRWXO);
+			if (asprintf(&modestr2, " (mode %o)",
+			    mode2 & modebits) == -1) {
+				err = got_error_from_errno("asprintf");
+				goto done;
+			}
+		}
+		n = fprintf(outfile, "blob - %s%s\n", idstr1,
+		    modestr1 ? modestr1 : "");
+		if (n < 0) {
+			err = got_error_from_errno("fprintf");
+			goto done;
+		}
+		outoff += n;
+		if (line_offsets) {
+			err = add_line_offset(line_offsets, nlines, outoff);
+			if (err)
+				goto done;
+		}
+
+		n = fprintf(outfile, "blob + %s%s\n", idstr2,
+		    modestr2 ? modestr2 : "");
+		if (n < 0) {
+			err = got_error_from_errno("fprintf");
+			goto done;
+		}
+		outoff += n;
+		if (line_offsets) {
+			err = add_line_offset(line_offsets, nlines, outoff);
+			if (err)
+				goto done;
+		}
+
+		free(modestr1);
+		free(modestr2);
+	}
+	err = got_diffreg(&result, f1, f2, GOT_DIFF_ALGORITHM_MYERS,
+	    ignore_whitespace);
+	if (err)
+		goto done;
+
+	if (outfile) {
+		err = got_diffreg_output(line_offsets, nlines, result, f1, f2,
+		    label1 ? label1 : idstr1,
+		    label2 ? label2 : idstr2,
+		    GOT_DIFF_OUTPUT_UNIDIFF, diff_context, outfile);
+		if (err)
+			goto done;
+	}
+
+	if (resultp && err == NULL)
+		*resultp = result;
+	else {
+		free_err = got_diffreg_result_free(result);
+		if (free_err && err == NULL)
+			err = free_err;
+	}
+done:
+	if (f1 && fclose(f1) != 0 && err == NULL)
+		err = got_error_from_errno("fclose");
+	if (f2 && fclose(f2) != 0 && err == NULL)
+		err = got_error_from_errno("fclose");
+	return err;
+}
+
+const struct got_error *
+got_diff_blob_output_unidiff(void *arg, struct got_blob_object *blob1,
+    struct got_blob_object *blob2, struct got_object_id *id1,
+    struct got_object_id *id2, const char *label1, const char *label2,
+    mode_t mode1, mode_t mode2, struct got_repository *repo)
+{
+	struct got_diff_blob_output_unidiff_arg *a = arg;
+
+	return diff_blobs(&a->line_offsets, &a->nlines, NULL,
+	    blob1, blob2, label1, label2, mode1, mode2, a->diff_context,
+	    a->ignore_whitespace, a->outfile);
+}
+
+const struct got_error *
+got_diff_blob(off_t **line_offsets, size_t *nlines,
+    struct got_blob_object *blob1, struct got_blob_object *blob2,
+    const char *label1, const char *label2, int diff_context,
+    int ignore_whitespace, FILE *outfile)
+{
+	return diff_blobs(line_offsets, nlines, NULL, blob1, blob2,
+	    label1, label2, 0, 0, diff_context, ignore_whitespace, outfile);
+}
+
+static const struct got_error *
+diff_blob_file(struct got_diffreg_result **resultp,
+    struct got_blob_object *blob1, const char *label1, FILE *f2, size_t size2,
+    const char *label2, int diff_context, int ignore_whitespace, FILE *outfile)
+{
+	const struct got_error *err = NULL, *free_err;
+	FILE *f1 = NULL;
+	char hex1[SHA1_DIGEST_STRING_LENGTH];
+	char *idstr1 = NULL;
+	size_t size1;
+	struct got_diffreg_result *result = NULL;
+
+	if (resultp)
+		*resultp = NULL;
+
+	size1 = 0;
+	if (blob1) {
+		f1 = got_opentemp();
+		if (f1 == NULL)
+			return got_error_from_errno("got_opentemp");
+		idstr1 = got_object_blob_id_str(blob1, hex1, sizeof(hex1));
+		err = got_object_blob_dump_to_file(&size1, NULL, NULL, f1,
+		    blob1);
+		if (err)
+			goto done;
+	} else {
+		idstr1 = "/dev/null";
+	}
+
+	if (outfile) {
+		fprintf(outfile, "blob - %s\n", label1 ? label1 : idstr1);
+		fprintf(outfile, "file + %s\n",
+		    f2 == NULL ? "/dev/null" : label2);
+	}
+
+	err = got_diffreg(&result, f1, f2, GOT_DIFF_ALGORITHM_MYERS, 
+	    ignore_whitespace);
+	if (err)
+		goto done;
+
+	if (outfile) {
+		err = got_diffreg_output(NULL, NULL, result, f1, f2,
+		    label2, label2, GOT_DIFF_OUTPUT_UNIDIFF, diff_context,
+		    outfile);
+		if (err)
+			goto done;
+	}
+
+	if (resultp && err == NULL)
+		*resultp = result;
+	else if (result) {
+		free_err = got_diffreg_result_free(result);
+		if (free_err && err == NULL)
+			err = free_err;
+	}
+done:
+	if (f1 && fclose(f1) != 0 && err == NULL)
+		err = got_error_from_errno("fclose");
+	return err;
+}
+
+const struct got_error *
+got_diff_blob_file(struct got_blob_object *blob1, const char *label1,
+    FILE *f2, size_t size2, const char *label2, int diff_context,
+    int ignore_whitespace, FILE *outfile)
+{
+	return diff_blob_file(NULL, blob1, label1, f2, size2, label2,
+	    diff_context, ignore_whitespace, outfile);
+}
+
+const struct got_error *
+got_diff_blob_file_lines_changed(struct got_diffreg_result **result,
+    struct got_blob_object *blob1, FILE *f2, size_t size2)
+{
+	return diff_blob_file(result, blob1, NULL, f2, size2, NULL,
+	    0, 0, NULL);
+}
+
+const struct got_error *
+got_diff_blob_lines_changed(struct got_diffreg_result **result,
+    struct got_blob_object *blob1, struct got_blob_object *blob2)
+{
+	const struct got_error *err = NULL;
+
+	err = diff_blobs(NULL, NULL, result, blob1, blob2,
+	    NULL, NULL, 0, 0, 3, 0, NULL);
+	if (err) {
+		got_diffreg_result_free(*result);
+		*result = NULL;
+	}
+	return err;
+}
+
+static const struct got_error *
+diff_added_blob(struct got_object_id *id, const char *label, mode_t mode,
+    struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg)
+{
+	const struct got_error *err;
+	struct got_blob_object  *blob = NULL;
+	struct got_object *obj = NULL;
+
+	err = got_object_open(&obj, repo, id);
+	if (err)
+		return err;
+
+	err = got_object_blob_open(&blob, repo, obj, 8192);
+	if (err)
+		goto done;
+	err = cb(cb_arg, NULL, blob, NULL, id, NULL, label, 0, mode, repo);
+done:
+	got_object_close(obj);
+	if (blob)
+		got_object_blob_close(blob);
+	return err;
+}
+
+static const struct got_error *
+diff_modified_blob(struct got_object_id *id1, struct got_object_id *id2,
+    const char *label1, const char *label2, mode_t mode1, mode_t mode2,
+    struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg)
+{
+	const struct got_error *err;
+	struct got_object *obj1 = NULL;
+	struct got_object *obj2 = NULL;
+	struct got_blob_object *blob1 = NULL;
+	struct got_blob_object *blob2 = NULL;
+
+	err = got_object_open(&obj1, repo, id1);
+	if (err)
+		return err;
+	if (obj1->type != GOT_OBJ_TYPE_BLOB) {
+		err = got_error(GOT_ERR_OBJ_TYPE);
+		goto done;
+	}
+
+	err = got_object_open(&obj2, repo, id2);
+	if (err)
+		goto done;
+	if (obj2->type != GOT_OBJ_TYPE_BLOB) {
+		err = got_error(GOT_ERR_BAD_OBJ_DATA);
+		goto done;
+	}
+
+	err = got_object_blob_open(&blob1, repo, obj1, 8192);
+	if (err)
+		goto done;
+
+	err = got_object_blob_open(&blob2, repo, obj2, 8192);
+	if (err)
+		goto done;
+
+	err = cb(cb_arg, blob1, blob2, id1, id2, label1, label2, mode1, mode2,
+	    repo);
+done:
+	if (obj1)
+		got_object_close(obj1);
+	if (obj2)
+		got_object_close(obj2);
+	if (blob1)
+		got_object_blob_close(blob1);
+	if (blob2)
+		got_object_blob_close(blob2);
+	return err;
+}
+
+static const struct got_error *
+diff_deleted_blob(struct got_object_id *id, const char *label, mode_t mode,
+    struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg)
+{
+	const struct got_error *err;
+	struct got_blob_object  *blob = NULL;
+	struct got_object *obj = NULL;
+
+	err = got_object_open(&obj, repo, id);
+	if (err)
+		return err;
+
+	err = got_object_blob_open(&blob, repo, obj, 8192);
+	if (err)
+		goto done;
+	err = cb(cb_arg, blob, NULL, id, NULL, label, NULL, mode, 0, repo);
+done:
+	got_object_close(obj);
+	if (blob)
+		got_object_blob_close(blob);
+	return err;
+}
+
+static const struct got_error *
+diff_added_tree(struct got_object_id *id, const char *label,
+    struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
+    int diff_content)
+{
+	const struct got_error *err = NULL;
+	struct got_object *treeobj = NULL;
+	struct got_tree_object *tree = NULL;
+
+	err = got_object_open(&treeobj, repo, id);
+	if (err)
+		goto done;
+
+	if (treeobj->type != GOT_OBJ_TYPE_TREE) {
+		err = got_error(GOT_ERR_OBJ_TYPE);
+		goto done;
+	}
+
+	err = got_object_tree_open(&tree, repo, treeobj);
+	if (err)
+		goto done;
+
+	err = got_diff_tree(NULL, tree, NULL, label, repo, cb, cb_arg,
+	    diff_content);
+done:
+	if (tree)
+		got_object_tree_close(tree);
+	if (treeobj)
+		got_object_close(treeobj);
+	return err;
+}
+
+static const struct got_error *
+diff_modified_tree(struct got_object_id *id1, struct got_object_id *id2,
+    const char *label1, const char *label2, struct got_repository *repo,
+    got_diff_blob_cb cb, void *cb_arg, int diff_content)
+{
+	const struct got_error *err;
+	struct got_object *treeobj1 = NULL;
+	struct got_object *treeobj2 = NULL;
+	struct got_tree_object *tree1 = NULL;
+	struct got_tree_object *tree2 = NULL;
+
+	err = got_object_open(&treeobj1, repo, id1);
+	if (err)
+		goto done;
+
+	if (treeobj1->type != GOT_OBJ_TYPE_TREE) {
+		err = got_error(GOT_ERR_OBJ_TYPE);
+		goto done;
+	}
+
+	err = got_object_open(&treeobj2, repo, id2);
+	if (err)
+		goto done;
+
+	if (treeobj2->type != GOT_OBJ_TYPE_TREE) {
+		err = got_error(GOT_ERR_OBJ_TYPE);
+		goto done;
+	}
+
+	err = got_object_tree_open(&tree1, repo, treeobj1);
+	if (err)
+		goto done;
+
+	err = got_object_tree_open(&tree2, repo, treeobj2);
+	if (err)
+		goto done;
+
+	err = got_diff_tree(tree1, tree2, label1, label2, repo, cb, cb_arg,
+	    diff_content);
+
+done:
+	if (tree1)
+		got_object_tree_close(tree1);
+	if (tree2)
+		got_object_tree_close(tree2);
+	if (treeobj1)
+		got_object_close(treeobj1);
+	if (treeobj2)
+		got_object_close(treeobj2);
+	return err;
+}
+
+static const struct got_error *
+diff_deleted_tree(struct got_object_id *id, const char *label,
+    struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
+    int diff_content)
+{
+	const struct got_error *err;
+	struct got_object *treeobj = NULL;
+	struct got_tree_object *tree = NULL;
+
+	err = got_object_open(&treeobj, repo, id);
+	if (err)
+		goto done;
+
+	if (treeobj->type != GOT_OBJ_TYPE_TREE) {
+		err = got_error(GOT_ERR_OBJ_TYPE);
+		goto done;
+	}
+
+	err = got_object_tree_open(&tree, repo, treeobj);
+	if (err)
+		goto done;
+
+	err = got_diff_tree(tree, NULL, label, NULL, repo, cb, cb_arg,
+	    diff_content);
+done:
+	if (tree)
+		got_object_tree_close(tree);
+	if (treeobj)
+		got_object_close(treeobj);
+	return err;
+}
+
+static const struct got_error *
+diff_kind_mismatch(struct got_object_id *id1, struct got_object_id *id2,
+    const char *label1, const char *label2, struct got_repository *repo,
+    got_diff_blob_cb cb, void *cb_arg)
+{
+	/* XXX TODO */
+	return NULL;
+}
+
+static const struct got_error *
+diff_entry_old_new(struct got_tree_entry *te1,
+    struct got_tree_entry *te2, const char *label1, const char *label2,
+    struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
+    int diff_content)
+{
+	const struct got_error *err = NULL;
+	int id_match;
+
+	if (got_object_tree_entry_is_submodule(te1))
+		return NULL;
+
+	if (te2 == NULL) {
+		if (S_ISDIR(te1->mode))
+			err = diff_deleted_tree(&te1->id, label1, repo,
+			    cb, cb_arg, diff_content);
+		else {
+			if (diff_content)
+				err = diff_deleted_blob(&te1->id, label1,
+				    te1->mode, repo, cb, cb_arg);
+			else
+				err = cb(cb_arg, NULL, NULL, &te1->id, NULL,
+				    label1, NULL, te1->mode, 0, repo);
+		}
+		return err;
+	} else if (got_object_tree_entry_is_submodule(te2))
+		return NULL;
+
+	id_match = (got_object_id_cmp(&te1->id, &te2->id) == 0);
+	if (S_ISDIR(te1->mode) && S_ISDIR(te2->mode)) {
+		if (!id_match)
+			return diff_modified_tree(&te1->id, &te2->id,
+			    label1, label2, repo, cb, cb_arg, diff_content);
+	} else if ((S_ISREG(te1->mode) || S_ISLNK(te1->mode)) &&
+	    (S_ISREG(te2->mode) || S_ISLNK(te2->mode))) {
+		if (!id_match ||
+		    ((te1->mode & (S_IFLNK | S_IXUSR))) !=
+		    (te2->mode & (S_IFLNK | S_IXUSR))) {
+			if (diff_content)
+				return diff_modified_blob(&te1->id, &te2->id,
+				    label1, label2, te1->mode, te2->mode,
+				    repo, cb, cb_arg);
+			else
+				return cb(cb_arg, NULL, NULL, &te1->id,
+				    &te2->id, label1, label2, te1->mode,
+				    te2->mode, repo);
+		}
+	}
+
+	if (id_match)
+		return NULL;
+
+	return diff_kind_mismatch(&te1->id, &te2->id, label1, label2, repo,
+	    cb, cb_arg);
+}
+
+static const struct got_error *
+diff_entry_new_old(struct got_tree_entry *te2,
+    struct got_tree_entry *te1, const char *label2,
+    struct got_repository *repo, got_diff_blob_cb cb, void *cb_arg,
+    int diff_content)
+{
+	if (te1 != NULL) /* handled by diff_entry_old_new() */
+		return NULL;
+
+	if (got_object_tree_entry_is_submodule(te2))
+		return NULL;
+
+	if (S_ISDIR(te2->mode))
+		return diff_added_tree(&te2->id, label2, repo, cb, cb_arg,
+		    diff_content);
+
+	if (diff_content)
+		return diff_added_blob(&te2->id, label2, te2->mode, repo, cb,
+		    cb_arg);
+
+	return cb(cb_arg, NULL, NULL, NULL, &te2->id, NULL, label2, 0,
+	    te2->mode, repo);
+}
+
+const struct got_error *
+got_diff_tree_collect_changed_paths(void *arg, struct got_blob_object *blob1,
+    struct got_blob_object *blob2, struct got_object_id *id1,
+    struct got_object_id *id2, const char *label1, const char *label2,
+    mode_t mode1, mode_t mode2, struct got_repository *repo)
+{
+	const struct got_error *err = NULL;
+	struct got_pathlist_head *paths = arg;
+	struct got_diff_changed_path *change = NULL;
+	char *path = NULL;
+
+	path = strdup(label2 ? label2 : label1);
+	if (path == NULL)
+		return got_error_from_errno("malloc");
+
+	change = malloc(sizeof(*change));
+	if (change == NULL) {
+		err = got_error_from_errno("malloc");
+		goto done;
+	}
+
+	change->status = GOT_STATUS_NO_CHANGE;
+	if (id1 == NULL)
+		change->status = GOT_STATUS_ADD;
+	else if (id2 == NULL)
+		change->status = GOT_STATUS_DELETE;
+	else {
+		if (got_object_id_cmp(id1, id2) != 0)
+			change->status = GOT_STATUS_MODIFY;
+		else if (mode1 != mode2)
+			change->status = GOT_STATUS_MODE_CHANGE;
+	}
+
+	err = got_pathlist_insert(NULL, paths, path, change);
+done:
+	if (err) {
+		free(path);
+		free(change);
+	}
+	return err;
+}
+
+const struct got_error *
+got_diff_tree(struct got_tree_object *tree1, struct got_tree_object *tree2,
+    const char *label1, const char *label2, struct got_repository *repo,
+    got_diff_blob_cb cb, void *cb_arg, int diff_content)
+{
+	const struct got_error *err = NULL;
+	struct got_tree_entry *te1 = NULL;
+	struct got_tree_entry *te2 = NULL;
+	char *l1 = NULL, *l2 = NULL;
+	int tidx1 = 0, tidx2 = 0;
+
+	if (tree1) {
+		te1 = got_object_tree_get_entry(tree1, 0);
+		if (te1 && asprintf(&l1, "%s%s%s", label1, label1[0] ? "/" : "",
+		    te1->name) == -1)
+			return got_error_from_errno("asprintf");
+	}
+	if (tree2) {
+		te2 = got_object_tree_get_entry(tree2, 0);
+		if (te2 && asprintf(&l2, "%s%s%s", label2, label2[0] ? "/" : "",
+		    te2->name) == -1)
+			return got_error_from_errno("asprintf");
+	}
+
+	do {
+		if (te1) {
+			struct got_tree_entry *te = NULL;
+			if (tree2)
+				te = got_object_tree_find_entry(tree2,
+				    te1->name);
+			if (te) {
+				free(l2);
+				l2 = NULL;
+				if (te && asprintf(&l2, "%s%s%s", label2,
+				    label2[0] ? "/" : "", te->name) == -1)
+					return
+					    got_error_from_errno("asprintf");
+			}
+			err = diff_entry_old_new(te1, te, l1, l2, repo, cb,
+			    cb_arg, diff_content);
+			if (err)
+				break;
+		}
+
+		if (te2) {
+			struct got_tree_entry *te = NULL;
+			if (tree1)
+				te = got_object_tree_find_entry(tree1,
+				    te2->name);
+			free(l2);
+			if (te) {
+				if (asprintf(&l2, "%s%s%s", label2,
+				    label2[0] ? "/" : "", te->name) == -1)
+					return
+					    got_error_from_errno("asprintf");
+			} else {
+				if (asprintf(&l2, "%s%s%s", label2,
+				    label2[0] ? "/" : "", te2->name) == -1)
+					return
+					    got_error_from_errno("asprintf");
+			}
+			err = diff_entry_new_old(te2, te, l2, repo,
+			    cb, cb_arg, diff_content);
+			if (err)
+				break;
+		}
+
+		free(l1);
+		l1 = NULL;
+		if (te1) {
+			tidx1++;
+			te1 = got_object_tree_get_entry(tree1, tidx1);
+			if (te1 &&
+			    asprintf(&l1, "%s%s%s", label1,
+			    label1[0] ? "/" : "", te1->name) == -1)
+				return got_error_from_errno("asprintf");
+		}
+		free(l2);
+		l2 = NULL;
+		if (te2) {
+			tidx2++;
+			te2 = got_object_tree_get_entry(tree2, tidx2);
+			if (te2 &&
+			    asprintf(&l2, "%s%s%s", label2,
+			        label2[0] ? "/" : "", te2->name) == -1)
+				return got_error_from_errno("asprintf");
+		}
+	} while (te1 || te2);
+
+	return err;
+}
+
+const struct got_error *
+got_diff_objects_as_blobs(off_t **line_offsets, size_t *nlines,
+    struct got_object_id *id1, struct got_object_id *id2,
+    const char *label1, const char *label2, int diff_context,
+    int ignore_whitespace, struct got_repository *repo, FILE *outfile)
+{
+	const struct got_error *err;
+	struct got_blob_object *blob1 = NULL, *blob2 = NULL;
+
+	if (id1 == NULL && id2 == NULL)
+		return got_error(GOT_ERR_NO_OBJ);
+
+	if (id1) {
+		err = got_object_open_as_blob(&blob1, repo, id1, 8192);
+		if (err)
+			goto done;
+	}
+	if (id2) {
+		err = got_object_open_as_blob(&blob2, repo, id2, 8192);
+		if (err)
+			goto done;
+	}
+	err = got_diff_blob(line_offsets, nlines, blob1, blob2,
+	    label1, label2, diff_context, ignore_whitespace, outfile);
+done:
+	if (blob1)
+		got_object_blob_close(blob1);
+	if (blob2)
+		got_object_blob_close(blob2);
+	return err;
+}
+
+const struct got_error *
+got_diff_objects_as_trees(off_t **line_offsets, size_t *nlines,
+    struct got_object_id *id1, struct got_object_id *id2,
+    char *label1, char *label2, int diff_context, int ignore_whitespace,
+    struct got_repository *repo, FILE *outfile)
+{
+	const struct got_error *err;
+	struct got_tree_object *tree1 = NULL, *tree2 = NULL;
+	struct got_diff_blob_output_unidiff_arg arg;
+	int want_lineoffsets = (line_offsets != NULL && *line_offsets != NULL);
+
+	if (id1 == NULL && id2 == NULL)
+		return got_error(GOT_ERR_NO_OBJ);
+
+	if (id1) {
+		err = got_object_open_as_tree(&tree1, repo, id1);
+		if (err)
+			goto done;
+	}
+	if (id2) {
+		err = got_object_open_as_tree(&tree2, repo, id2);
+		if (err)
+			goto done;
+	}
+	arg.diff_context = diff_context;
+	arg.ignore_whitespace = ignore_whitespace;
+	arg.outfile = outfile;
+	if (want_lineoffsets) {
+		arg.line_offsets = *line_offsets;
+		arg.nlines = *nlines;
+	} else {
+		arg.line_offsets = NULL;
+		arg.nlines = 0;
+	}
+	err = got_diff_tree(tree1, tree2, label1, label2, repo,
+	    got_diff_blob_output_unidiff, &arg, 1);
+
+	if (want_lineoffsets) {
+		*line_offsets = arg.line_offsets; /* was likely re-allocated */
+		*nlines = arg.nlines;
+	}
+done:
+	if (tree1)
+		got_object_tree_close(tree1);
+	if (tree2)
+		got_object_tree_close(tree2);
+	return err;
+}
+
+const struct got_error *
+got_diff_objects_as_commits(off_t **line_offsets, size_t *nlines,
+    struct got_object_id *id1, struct got_object_id *id2,
+    int diff_context, int ignore_whitespace,
+    struct got_repository *repo, FILE *outfile)
+{
+	const struct got_error *err;
+	struct got_commit_object *commit1 = NULL, *commit2 = NULL;
+
+	if (id2 == NULL)
+		return got_error(GOT_ERR_NO_OBJ);
+
+	if (id1) {
+		err = got_object_open_as_commit(&commit1, repo, id1);
+		if (err)
+			goto done;
+	}
+
+	err = got_object_open_as_commit(&commit2, repo, id2);
+	if (err)
+		goto done;
+
+	err = got_diff_objects_as_trees(line_offsets, nlines,
+	    commit1 ? got_object_commit_get_tree_id(commit1) : NULL,
+	    got_object_commit_get_tree_id(commit2), "", "", diff_context,
+	    ignore_whitespace, repo, outfile);
+done:
+	if (commit1)
+		got_object_commit_close(commit1);
+	if (commit2)
+		got_object_commit_close(commit2);
+	return err;
+}
+
+const struct got_error *
+got_diff_files(struct got_diffreg_result **resultp,
+    FILE *f1, const char *label1, FILE *f2, const char *label2,
+    int diff_context, int ignore_whitespace, FILE *outfile)
+{
+	const struct got_error *err = NULL;
+	struct got_diffreg_result *diffreg_result = NULL;
+
+	if (resultp)
+		*resultp = NULL;
+
+	if (outfile) {
+		fprintf(outfile, "file - %s\n",
+		    f1 == NULL ? "/dev/null" : label1);
+		fprintf(outfile, "file + %s\n",
+		    f2 == NULL ? "/dev/null" : label2);
+	}
+
+	err = got_diffreg(&diffreg_result, f1, f2, GOT_DIFF_ALGORITHM_MYERS,
+	    ignore_whitespace);
+	if (err)
+		goto done;
+
+	if (outfile) {
+		err = got_diffreg_output(NULL, NULL, diffreg_result,
+		    f1, f2, label1, label2, GOT_DIFF_OUTPUT_UNIDIFF,
+		    diff_context, outfile);
+		if (err)
+			goto done;
+	}
+
+done:
+	if (resultp && err == NULL)
+		*resultp = diffreg_result;
+	else if (diffreg_result) {
+		const struct got_error *free_err;
+		free_err = got_diffreg_result_free(diffreg_result);
+		if (free_err && err == NULL)
+			err = free_err;
+	}
+
+	return err;
+}