Subject: Re: [PATCH 1/4] Add git-archive

From: Franck Bui-Huu <[email-masked]>
Date: Fri, 08 Sep 2006 11:00:04 +0200

Junio C Hamano wrote:
> Franck Bui-Huu <[email-masked]> writes:
> 
[snip]
> 
> Does your code work well when you run the remote archive
> fetching locally, i.e. "git-archive --remote=../other.git",
> I wonder?
> 
> ... goes on and reads the patch, notices that the protocol
> command is git-upload-archive with the archive location.  Which
> is GOOD.  It is just the above description is a tad stale.
> 

yeah, sorry for that. I forgot to update the patch description.

>> diff --git a/archive.h b/archive.h
>> new file mode 100644
>> index 0000000..f33398e
>> --- /dev/null
>> +++ b/archive.h
>> @@ -0,0 +1,41 @@
>> +#ifndef ARCHIVE_H
>> +#define ARCHIVE_H
>> +
>> +#define MAX_EXTRA_ARGS	32
>> +#define MAX_ARGS	(MAX_EXTRA_ARGS + 32)
>> +

[snip]

> 
> I thought the reason for archiver_args (and archiver_args.extra)
> was because we wanted to avoid storing per invocation parameters
> in static variables, which would hamper reentrancy.  If one
> process is creating two archives, both format=tar, it might be
> reasonable for the code (future archiver enhancement, not your
> current implementation of git-archive driver) to parse two sets
> of parameters first (to get separate archiver instances) and
> call their write_archive, but if archivers[] list has the
> per-invocation parameter args then we are back to square one,
> aren't we?
> 
> Reentrancy may not matter, but in any case the above archiver_args
> is not helping enough to improve the situation, I think.
> 
> Actually you may be able to get away by returning a copy of
> archivers[] element from get_archiver() when we need reentrancy
> in the future.  Of course the caller needs to free() it when it
> is done with it, since it is a per-invocation handle.
> 

yup I did half work here. Does the following is ok now ?

-- >8 --

Subject: Add git-archive

git-archive is a command to make TAR and ZIP archives of a git tree.
It helps prevent a proliferation of git-{format}-tree commands.

Instead of directly calling git-{tar,zip}-tree command, it defines
a very simple API, that archiver should implement and register in
"git-archive.c". This API is made up by 2 functions whose prototype
is defined in "archive.h" file.

 - The first one is used to parse 'extra' parameters which have
   signification only for the specific archiver. That would allow
   different archive backends to have different kind of options.

 - The second one is used to ask to an archive backend to build
   the archive given some already resolved parameters.

It also implements remote operations by defining a very simple
protocol: it first sends 'git-upload-archive' followed the
repository name. Then it sends options. It's done by sending a
sequence of one argument per packet, with prefix "argument ",
followed by a flush.

The remote protocol is implemented in "git-archive.c" for client
side and is triggered by "--remote=<repo>" option. For example,
to fetch a TAR archive in a remote repo, you can issue:

$ git archive --format=tar --remote=git://xxx/yyy/zzz.git HEAD

We choose to not make a new command "git-fetch-archive" for example,
avoind one more GIT command which should be nice for users (less
commands to remember, keeps existing --remote option).

Signed-off-by: Franck Bui-Huu <[email-masked]>
---
 .gitignore                    |    1 
 Documentation/git-archive.txt |  100 ++++++++++++++++++
 Makefile                      |    3 -
 archive.h                     |   41 +++++++
 builtin-archive.c             |  225 +++++++++++++++++++++++++++++++++++++++++
 builtin.h                     |    1 
 generate-cmdlist.sh           |    1 
 git.c                         |    1 
 8 files changed, 372 insertions(+), 1 deletions(-)

diff --git a/.gitignore b/.gitignore
index 78cb671..a3e7ca1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,6 +8,7 @@ git-apply
 git-applymbox
 git-applypatch
 git-archimport
+git-archive
 git-bisect
 git-branch
 git-cat-file
diff --git a/Documentation/git-archive.txt b/Documentation/git-archive.txt
new file mode 100644
index 0000000..913528d
--- /dev/null
+++ b/Documentation/git-archive.txt
@@ -0,0 +1,100 @@
+git-archive(1)
+==============
+
+NAME
+----
+git-archive - Creates a archive of the files in the named tree
+
+
+SYNOPSIS
+--------
+'git-archive' --format=<fmt> [--list] [--prefix=<prefix>/] [<extra>]
+	      [--remote=<repo>] <tree-ish> [path...]
+
+DESCRIPTION
+-----------
+Creates an archive of the specified format containing the tree
+structure for the named tree.  If <prefix> is specified it is
+prepended to the filenames in the archive.
+
+'git-archive' behaves differently when given a tree ID versus when
+given a commit ID or tag ID.  In the first case the current time is
+used as modification time of each file in the archive.  In the latter
+case the commit time as recorded in the referenced commit object is
+used instead.  Additionally the commit ID is stored in a global
+extended pax header if the tar format is used; it can be extracted
+using 'git-get-tar-commit-id'. In ZIP files it is stored as a file
+comment.
+
+OPTIONS
+-------
+
+--format=<fmt>::
+	Format of the resulting archive: 'tar', 'zip'...
+
+--list::
+	Show all available formats.
+
+--prefix=<prefix>/::
+	Prepend <prefix>/ to each filename in the archive.
+
+<extra>::
+	This can be any options that the archiver backend understand.
+
+--remote=<repo>::
+	Instead of making a tar archive from local repository,
+	retrieve a tar archive from a remote repository.
+
+<tree-ish>::
+	The tree or commit to produce an archive for.
+
+path::
+	If one or more paths are specified, include only these in the
+	archive, otherwise include all files and subdirectories.
+
+CONFIGURATION
+-------------
+By default, file and directories modes are set to 0666 or 0777 in tar
+archives.  It is possible to change this by setting the "umask" variable
+in the repository configuration as follows :
+
+[tar]
+        umask = 002	;# group friendly
+
+The special umask value "user" indicates that the user's current umask
+will be used instead. The default value remains 0, which means world
+readable/writable files and directories.
+
+EXAMPLES
+--------
+git archive --format=tar --prefix=junk/ HEAD | (cd /var/tmp/ && tar xf -)::
+
+	Create a tar archive that contains the contents of the
+	latest commit on the current branch, and extracts it in
+	`/var/tmp/junk` directory.
+
+git archive --format=tar --prefix=git-1.4.0/ v1.4.0 | gzip >git-1.4.0.tar.gz::
+
+	Create a compressed tarball for v1.4.0 release.
+
+git archive --format=tar --prefix=git-1.4.0/ v1.4.0{caret}\{tree\} | gzip >git-1.4.0.tar.gz::
+
+	Create a compressed tarball for v1.4.0 release, but without a
+	global extended pax header.
+
+git archive --format=zip --prefix=git-docs/ HEAD:Documentation/ > git-1.4.0-docs.zip::
+
+	Put everything in the current head's Documentation/ directory
+	into 'git-1.4.0-docs.zip', with the prefix 'git-docs/'.
+
+Author
+------
+Written by Franck Bui-Huu and Rene Scharfe.
+
+Documentation
+--------------
+Documentation by David Greaves, Junio C Hamano and the git-list <[email-masked]>.
+
+GIT
+---
+Part of the gitlink:git[7] suite
diff --git a/Makefile b/Makefile
index 389daf7..51ed4dd 100644
--- a/Makefile
+++ b/Makefile
@@ -242,7 +242,7 @@ LIB_FILE=libgit.a
 XDIFF_LIB=xdiff/lib.a
 
 LIB_H = \
-	blob.h cache.h commit.h csum-file.h delta.h \
+	archive.h blob.h cache.h commit.h csum-file.h delta.h \
 	diff.h object.h pack.h para-walk.h pkt-line.h quote.h refs.h \
 	run-command.h strbuf.h tag.h tree.h git-compat-util.h revision.h \
 	tree-walk.h log-tree.h dir.h path-list.h unpack-trees.h builtin.h
@@ -267,6 +267,7 @@ LIB_OBJS = \
 BUILTIN_OBJS = \
 	builtin-add.o \
 	builtin-apply.o \
+	builtin-archive.o \
 	builtin-cat-file.o \
 	builtin-checkout-index.o \
 	builtin-check-ref-format.o \
diff --git a/archive.h b/archive.h
new file mode 100644
index 0000000..24b016f
--- /dev/null
+++ b/archive.h
@@ -0,0 +1,41 @@
+#ifndef ARCHIVE_H
+#define ARCHIVE_H
+
+#define MAX_EXTRA_ARGS	32
+#define MAX_ARGS	(MAX_EXTRA_ARGS + 32)
+
+struct archiver_args {
+	const char *base;
+	struct tree *tree;
+	const unsigned char *commit_sha1;
+	time_t time;
+	const char **pathspec;
+	void *extra;
+};
+
+typedef int (*write_archive_fn_t)(struct archiver_args *);
+
+typedef void *(*parse_extra_args_fn_t)(int argc, const char **argv);
+
+struct archiver {
+	const char *name;
+	const char *remote;
+	struct archiver_args args;
+	write_archive_fn_t write_archive;
+	parse_extra_args_fn_t parse_extra;
+};
+
+extern struct archiver archivers[];
+
+extern int parse_archive_args(int argc,
+			      const char **argv,
+			      struct archiver *ar);
+
+extern void parse_treeish_arg(const char **treeish,
+			      struct archiver_args *ar_args,
+			      const char *prefix);
+
+extern void parse_pathspec_arg(const char **pathspec,
+			       struct archiver_args *args);
+
+#endif	/* ARCHIVE_H */
diff --git a/builtin-archive.c b/builtin-archive.c
new file mode 100644
index 0000000..5671cbd
--- /dev/null
+++ b/builtin-archive.c
@@ -0,0 +1,225 @@
+/*
+ * Copyright (c) 2006 Franck Bui-Huu
+ * Copyright (c) 2006 Rene Scharfe
+ */
+#include <time.h>
+#include "cache.h"
+#include "builtin.h"
+#include "archive.h"
+#include "commit.h"
+#include "tree-walk.h"
+#include "exec_cmd.h"
+#include "pkt-line.h"
+
+static const char archive_usage[] = \
+"git-archive --format=<fmt> [--prefix=<prefix>/] [<extra>] <tree-ish> [path...]";
+
+
+struct archiver archivers[] = { };
+
+
+static int run_remote_archiver(struct archiver *ar, int argc,
+			       const char **argv)
+{
+	char *url, buf[1024];
+	int fd[2], i, len, rv;
+	pid_t pid;
+
+	sprintf(buf, "git-upload-archive");
+
+	url = strdup(ar->remote);
+	pid = git_connect(fd, url, buf);
+	if (pid < 0)
+		return pid;
+
+	for (i = 1; i < argc; i++) {
+		if (!strncmp(argv[i], "--remote=", 9))
+			continue;
+		packet_write(fd[1], "argument %s\n", argv[i]);
+	}
+	packet_flush(fd[1]);
+
+	len = packet_read_line(fd[0], buf, sizeof(buf));
+	if (!len)
+		die("git-archive: expected ACK/NAK, got EOF");
+	if (buf[len-1] == '\n')
+		buf[--len] = 0;
+	if (strcmp(buf, "ACK")) {
+		if (len > 5 && !strncmp(buf, "NACK ", 5))
+			die("git-archive: NACK %s", buf + 5);
+		die("git-archive: protocol error");
+	}
+
+	len = packet_read_line(fd[0], buf, sizeof(buf));
+	if (len)
+		die("git-archive: expected a flush");
+
+	/* Now, start reading from fd[0] and spit it out to stdout */
+	rv = copy_fd(fd[0], 1);
+
+	close(fd[0]);
+	rv |= finish_connect(pid);
+
+	return !!rv;
+}
+
+static int init_archiver(const char *name, struct archiver *ar)
+{
+	int rv = -1, i;
+
+	for (i = 0; i < ARRAY_SIZE(archivers); i++) {
+		if (!strcmp(name, archivers[i].name)) {
+			memcpy(ar, &archivers[i], sizeof(struct archiver));
+			rv = 0;
+			break;
+		}
+	}
+	return rv;
+}
+
+void parse_pathspec_arg(const char **pathspec, struct archiver_args *ar_args)
+{
+	ar_args->pathspec = get_pathspec(ar_args->base, pathspec);
+}
+
+void parse_treeish_arg(const char **argv, struct archiver_args *ar_args,
+		       const char *prefix)
+{
+	const char *name = argv[0];
+	const unsigned char *commit_sha1;
+	time_t archive_time;
+	struct tree *tree;
+	struct commit *commit;
+	unsigned char sha1[20];
+
+	if (get_sha1(name, sha1))
+		die("Not a valid object name");
+
+	commit = lookup_commit_reference_gently(sha1, 1);
+	if (commit) {
+		commit_sha1 = commit->object.sha1;
+		archive_time = commit->date;
+	} else {
+		archive_time = time(NULL);
+	}
+
+	tree = parse_tree_indirect(sha1);
+	if (tree == NULL)
+		die("not a tree object");
+
+	if (prefix) {
+		unsigned char tree_sha1[20];
+		unsigned int mode;
+		int err;
+
+		err = get_tree_entry(tree->object.sha1, prefix,
+				     tree_sha1, &mode);
+		if (err || !S_ISDIR(mode))
+			die("current working directory is untracked");
+
+		free(tree);
+		tree = parse_tree_indirect(tree_sha1);
+	}
+	ar_args->tree = tree;
+	ar_args->commit_sha1 = commit_sha1;
+	ar_args->time = archive_time;
+}
+
+static const char *default_parse_extra(struct archiver *ar,
+				       const char **argv)
+{
+	static char msg[64];
+
+	snprintf(msg, sizeof(msg) - 4, "'%s' format does not handle %s",
+		 ar->name, *argv);
+
+	return strcat(msg, "...");
+}
+
+int parse_archive_args(int argc, const char **argv, struct archiver *ar)
+{
+	const char *extra_argv[MAX_EXTRA_ARGS];
+	int extra_argc = 0;
+	const char *format = NULL; /* some default values */
+	const char *remote = NULL;
+	const char *base = "";
+	int list = 0;
+	int i;
+
+	for (i = 1; i < argc; i++) {
+		const char *arg = argv[i];
+
+		if (!strcmp(arg, "--list") || !strcmp(arg, "-l")) {
+			list = 1;
+			continue;
+		}
+		if (!strncmp(arg, "--format=", 9)) {
+			format = arg + 9;
+			continue;
+		}
+		if (!strncmp(arg, "--prefix=", 9)) {
+			base = arg + 9;
+			continue;
+		}
+		if (!strncmp(arg, "--remote=", 9)) {
+			remote = arg + 9;
+			continue;
+		}
+		if (!strcmp(arg, "--")) {
+			i++;
+			break;
+		}
+		if (arg[0] == '-') {
+			extra_argv[extra_argc++] = arg;
+			continue;
+		}
+		break;
+	}
+	if (list) {
+		if (!remote) {
+			for (i = 0; i < ARRAY_SIZE(archivers); i++)
+				printf("%s\n", archivers[i].name);
+			exit(0);
+		}
+		die("--list and --remote are mutually exclusive");
+	}
+	if (argc - i < 1) {
+		die("%s", archive_usage);
+	}
+	if (!format){
+		die("You must specify an archive format");
+	}
+	if (init_archiver(format, ar) < 0) {
+		die("Unknown archive format '%s'", format);
+	}
+	if (extra_argc && !remote) {
+		if (!ar->parse_extra) {
+			die("%s", default_parse_extra(ar, extra_argv));
+		}
+		ar->args.extra = ar->parse_extra(extra_argc, extra_argv);
+	}
+	ar->remote = remote;
+	ar->args.base = base;
+
+	return i;
+}
+
+int cmd_archive(int argc, const char **argv, const char *prefix)
+{
+	struct archiver ar;
+	int tree_idx;
+
+	tree_idx = parse_archive_args(argc, argv, &ar);
+
+	if (ar.remote)
+		return run_remote_archiver(&ar, argc, argv);
+
+	if (prefix == NULL)
+		prefix = setup_git_directory();
+
+	argv += tree_idx;
+	parse_treeish_arg(argv, &ar.args, prefix);
+	parse_pathspec_arg(argv + 1, &ar.args);
+
+	return ar.write_archive(&ar.args);
+}
diff --git a/builtin.h b/builtin.h
index 8472c79..2391afb 100644
--- a/builtin.h
+++ b/builtin.h
@@ -15,6 +15,7 @@ extern int write_tree(unsigned char *sha
 
 extern int cmd_add(int argc, const char **argv, const char *prefix);
 extern int cmd_apply(int argc, const char **argv, const char *prefix);
+extern int cmd_archive(int argc, const char **argv, const char *prefix);
 extern int cmd_cat_file(int argc, const char **argv, const char *prefix);
 extern int cmd_checkout_index(int argc, const char **argv, const char *prefix);
 extern int cmd_check_ref_format(int argc, const char **argv, const char *prefix);
diff --git a/generate-cmdlist.sh b/generate-cmdlist.sh
index ec1eda2..5450918 100755
--- a/generate-cmdlist.sh
+++ b/generate-cmdlist.sh
@@ -12,6 +12,7 @@ struct cmdname_help common_cmds[] = {"
 sort <<\EOF |
 add
 apply
+archive
 bisect
 branch
 checkout
diff --git a/git.c b/git.c
index 82c8fee..c62c5cf 100644
--- a/git.c
+++ b/git.c
@@ -218,6 +218,7 @@ static void handle_internal_command(int 
 	} commands[] = {
 		{ "add", cmd_add, RUN_SETUP },
 		{ "apply", cmd_apply },
+		{ "archive", cmd_archive },
 		{ "cat-file", cmd_cat_file, RUN_SETUP },
 		{ "checkout-index", cmd_checkout_index, RUN_SETUP },
 		{ "check-ref-format", cmd_check_ref_format },
-- 
1.4.2