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[PATCH] Add `git diff2`, a GNU diff workalike

From
Johannes Schindelin <johannes.schindelin@gmx.de>
Date
Feb 18, 2007, 11:44 UTC
Message-ID
<Pine.LNX.4.63.0702181243520.22628@wbgn013.biozentrum.uni-wuerzburg.de>
In-Reply-To
<7vtzxknrzp.fsf@assigned-by-dhcp.cox.net>

Git really has a wonderful diff engine. For example, colored diffs really shine, and there are other useful options like --check, --check, etc. I always dreamt of using this diff engine also outside of a git repository.

With this commit, you can say
	git diff2 file1 file2
to compare the (possibly untracked) files "file1" and "file2", and
	git diff2 dir1 dir2
to compare the directories "dir1" and "dir2".
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
	Junio tricked me into writing documentation, so be gentle.
	Back to bed.
 .gitignore                  |    1 +
 Documentation/cmd-list.perl |    1 +
 Documentation/git-diff2.txt |   63 +++++++++++++++++
 Makefile                    |    1 +
 builtin-diff2.c             |  163 +++++++++++++++++++++++++++++++++++++++++++
 builtin.h                   |    1 +
 diff.c                      |    3 +-
 git.c                       |    1 +
 8 files changed, 233 insertions(+), 1 deletions(-)
 create mode 100644 Documentation/git-diff2.txt
 create mode 100644 builtin-diff2.c
diff --git a/.gitignore b/.gitignore
index f15155d..7c653fb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -31,6 +31,7 @@ git-cvsimport
 git-cvsserver
 git-daemon
 git-diff
+git-diff2
 git-diff-files
 git-diff-index
 git-diff-tree
diff --git a/Documentation/cmd-list.perl b/Documentation/cmd-list.perl
index a2d6268..e2b0bd3 100755
--- a/Documentation/cmd-list.perl
+++ b/Documentation/cmd-list.perl
@@ -90,6 +90,7 @@ git-describe                            mainporcelain
 git-diff-files                          plumbinginterrogators
 git-diff-index                          plumbinginterrogators
 git-diff                                mainporcelain
+git-diff2                               mainporcelain
 git-diff-tree                           plumbinginterrogators
 git-fast-import				ancillarymanipulators
 git-fetch                               mainporcelain
diff --git a/Documentation/git-diff2.txt b/Documentation/git-diff2.txt
new file mode 100644
index 0000000..8909119
--- /dev/null
+++ b/Documentation/git-diff2.txt
@@ -0,0 +1,63 @@
+git-diff2(1)
+===========
+
+NAME
+----
+git-diff2 - Show changes between files, directories and symlinks
+
+
+SYNOPSIS
+--------
+'git-diff2' [ --diff-options ] <path1> <path2>
+
+DESCRIPTION
+-----------
+Show changes between two files, directories or symlinks.
+
+'git-diff2' [--options] [--] <path1> <path2>::
+
+	This command operates independently of a git repository.
+	It is meant to bring the full power of git's diff engine
+	to your files, without having to check them into a git
+	repository first.
+
+
+OPTIONS
+-------
+include::diff-options.txt[]
+
+<path1> <path2>::
+	The <paths> parameters are used to determine which files
+	should be compared against each other.
+
+
+EXAMPLES
+--------
+
+See the differences README.new has relative to README::
++
+------------
+$ git diff2 README README.new
+------------
++
+
+Check if there is white space breakage in the changes leading from
+old/ to new/::
++
+------------
+$ git diff2 --check old/ new/
+------------
++
+
+Author
+------
+Written by Johannes Schindelin <johannes.schindelin@gmx.de>
+
+Documentation
+--------------
+Documentation by Johannes Schindelin and the git-list <git@vger.kernel.org>.
+
+GIT
+---
+Part of the gitlink:git[7] suite
+
diff --git a/Makefile b/Makefile
index ebecbbd..39a1a09 100644
--- a/Makefile
+++ b/Makefile
@@ -278,6 +278,7 @@ BUILTIN_OBJS = \
 	builtin-count-objects.o \
 	builtin-describe.o \
 	builtin-diff.o \
+	builtin-diff2.o \
 	builtin-diff-files.o \
 	builtin-diff-index.o \
 	builtin-diff-tree.o \
diff --git a/builtin-diff2.c b/builtin-diff2.c
new file mode 100644
index 0000000..1de82c1
--- /dev/null
+++ b/builtin-diff2.c
@@ -0,0 +1,163 @@
+#include "cache.h"
+#include "diff.h"
+#include "diffcore.h"
+#include "path-list.h"
+
+static const char diff2_usage[] = "git diff2 [diff-opts] file1 file2";
+
+static int read_directory(const char *path, struct path_list *list)
+{
+	DIR *dir;
+	struct dirent *e;
+
+	if (!(dir = opendir(path)))
+		return error("Could not open directory %s", path);
+
+	while ((e = readdir(dir)))
+		if (strcmp(".", e->d_name) && strcmp("..", e->d_name))
+			path_list_insert(xstrdup(e->d_name), list);
+
+	closedir(dir);
+	return 0;
+}
+
+static int queue_diff(struct diff_options *o,
+		const char *name1, const char *name2)
+{
+	struct stat st;
+	int mode1 = 0, mode2 = 0;
+
+	if (name1) {
+		if (stat(name1, &st))
+			return error("Could not access '%s'", name1);
+		mode1 = st.st_mode;
+	}
+	if (name2) {
+		if (stat(name2, &st))
+			return error("Could not access '%s'", name1);
+		mode2 = st.st_mode;
+	}
+
+	if (mode1 && mode2 && S_ISDIR(mode1) != S_ISDIR(mode2))
+		return error("file/directory conflict: %s, %s", name1, name2);
+
+	if (S_ISDIR(mode1) || S_ISDIR(mode2)) {
+		char buffer1[PATH_MAX], buffer2[PATH_MAX];
+		struct path_list p1 = {NULL, 0, 0, 1}, p2 = {NULL, 0, 0, 1};
+		int len1 = 0, len2 = 0, i1, i2, ret = 0;
+
+		if (name1 && read_directory(name1, &p1))
+			return -1;
+		if (name2 && read_directory(name2, &p2)) {
+			path_list_clear(&p1, 0);
+			return -1;
+		}
+
+		if (name1) {
+			len1 = strlen(name1);
+			if (len1 > 0 && name1[len1 - 1] == '/')
+				len1--;
+			memcpy(buffer1, name1, len1);
+			buffer1[len1++] = '/';
+		}
+
+		if (name2) {
+			len2 = strlen(name2);
+			if (len2 > 0 && name2[len2 - 1] == '/')
+				len2--;
+			memcpy(buffer2, name2, len2);
+			buffer2[len2++] = '/';
+		}
+
+		for (i1 = i2 = 0; !ret && (i1 < p1.nr || i2 < p2.nr); ) {
+			const char *n1, *n2;
+			int comp;
+
+			if (i1 == p1.nr)
+				comp = 1;
+			else if (i2 == p2.nr)
+				comp = -1;
+			else
+				comp = strcmp(p1.items[i1].path,
+					p2.items[i2].path);
+
+			if (comp > 0)
+				n1 = NULL;
+			else {
+				n1 = buffer1;
+				strncpy(buffer1 + len1, p1.items[i1++].path,
+						PATH_MAX - len1);
+			}
+
+			if (comp < 0)
+				n2 = NULL;
+			else {
+				n2 = buffer2;
+				strncpy(buffer2 + len2, p2.items[i2++].path,
+						PATH_MAX - len2);
+			}
+
+			ret = queue_diff(o, n1, n2);
+		}
+		path_list_clear(&p1, 0);
+		path_list_clear(&p2, 0);
+
+		return ret;
+	} else {
+		struct diff_filespec *d1, *d2;
+
+		if (o->reverse_diff) {
+			unsigned tmp;
+			const char *tmp_c;
+			tmp = mode1; mode1 = mode2; mode2 = tmp;
+			tmp_c = name1; name1 = name2; name2 = tmp_c;
+		}
+
+		if (!name1)
+			name1 = "/dev/null";
+		if (!name2)
+			name2 = "/dev/null";
+		d1 = alloc_filespec(name1);
+		d2 = alloc_filespec(name2);
+		fill_filespec(d1, null_sha1, mode1);
+		fill_filespec(d2, null_sha1, mode2);
+
+		diff_queue(&diff_queued_diff, d1, d2);
+		return 0;
+	}
+}
+
+int cmd_diff2(int argc, char **argv, char **envp)
+{
+	struct diff_options options;
+	int i, i2;
+        int nongit = 0;
+
+        setup_git_directory_gently(&nongit);
+	git_config(git_diff_ui_config);
+
+	diff_setup(&options);
+	for (i = 1; i < argc; ) {
+		if (!strcmp("--", argv[i])) {
+			i++;
+			break;
+		}
+		i2 = diff_opt_parse(&options,
+				(const char **)argv + i, argc - i);
+		if (!i2)
+			break;
+		i += i2;
+	}
+	if (diff_setup_done(&options) < 0)
+		die("diff_setup_done failed");
+	if (!options.output_format)
+		options.output_format = DIFF_FORMAT_PATCH;
+
+	if (argc - i != 2)
+		usage(diff2_usage);
+
+	queue_diff(&options, argv[i], argv[i + 1]);
+	diffcore_std(&options);
+	diff_flush(&options);
+	return 0;
+}
diff --git a/builtin.h b/builtin.h
index 57e8741..b872ecc 100644
--- a/builtin.h
+++ b/builtin.h
@@ -29,6 +29,7 @@ extern int cmd_describe(int argc, const char **argv, const char *prefix);
 extern int cmd_diff_files(int argc, const char **argv, const char *prefix);
 extern int cmd_diff_index(int argc, const char **argv, const char *prefix);
 extern int cmd_diff(int argc, const char **argv, const char *prefix);
+extern int cmd_diff2(int argc, const char **argv, const char *prefix);
 extern int cmd_diff_tree(int argc, const char **argv, const char *prefix);
 extern int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix);
 extern int cmd_for_each_ref(int argc, const char **argv, const char *prefix);
diff --git a/diff.c b/diff.c
index 12c8b2b..701880a 100644
--- a/diff.c
+++ b/diff.c
@@ -2406,7 +2406,8 @@ static void diff_resolve_rename_copy(void)
 				p->status = DIFF_STATUS_RENAMED;
 		}
 		else if (hashcmp(p->one->sha1, p->two->sha1) ||
-			 p->one->mode != p->two->mode)
+			 p->one->mode != p->two->mode ||
+			 is_null_sha1(p->one->sha1))
 			p->status = DIFF_STATUS_MODIFIED;
 		else {
 			/* This is a "no-change" entry and should not
diff --git a/git.c b/git.c
index 4dd1967..dfeddf2 100644
--- a/git.c
+++ b/git.c
@@ -238,6 +238,7 @@ static void handle_internal_command(int argc, const char **argv, char **envp)
 		{ "count-objects", cmd_count_objects, RUN_SETUP },
 		{ "describe", cmd_describe, RUN_SETUP },
 		{ "diff", cmd_diff, RUN_SETUP | USE_PAGER },
+		{ "diff2", cmd_diff2, USE_PAGER },
 		{ "diff-files", cmd_diff_files, RUN_SETUP },
 		{ "diff-index", cmd_diff_index, RUN_SETUP },
 		{ "diff-tree", cmd_diff_tree, RUN_SETUP },

-- 
1.5.0.rc4.2449.ga6f47
Previous: Johannes Schindelin
Message 5 of 5 in “Add `git diff2`, a GNU diff workalike”
  1. Add `git diff2`, a GNU diff workalikeJohannes Schindelin, Feb 16, 2007
  2. Junio C HamanoFeb 16, 2007
  3. Johannes SchindelinFeb 16, 2007
  4. Johannes SchindelinFeb 16, 2007
  5. Add `git diff2`, a GNU diff workalikeJohannes Schindelin, Feb 18, 2007

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