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git-commit-vandalism/builtin-zip-tree.c
Rene Scharfe e4fbbfe9ec Add git-zip-tree 
In the Windows world ZIP files are better supported than tar files.
Windows even includes built-in support for ZIP files nowadays.

git-zip-tree is similar to git-tar-tree; it creates ZIP files out of
git trees.  It stores the commit ID (if available) in a ZIP file comment
which can be extracted by unzip.

There's still quite some room for improvement: this initial version
supports no symlinks, calls write() way too often (three times per file)
and there is no unit test.

[jc: with a minor typefix to avoid void* arithmetic]

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-08-26 18:27:35 -07:00

354 lines
8.6 KiB
C
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/*
* Copyright (c) 2006 Rene Scharfe
*/
#include <time.h>
#include "cache.h"
#include "commit.h"
#include "blob.h"
#include "tree.h"
#include "quote.h"
#include "builtin.h"
static const char zip_tree_usage[] =
"git-zip-tree [-0|...|-9] <tree-ish> [ <base> ]";
static int zip_date;
static int zip_time;
static unsigned char *zip_dir;
static unsigned int zip_dir_size;
static unsigned int zip_offset;
static unsigned int zip_dir_offset;
static unsigned int zip_dir_entries;
#define ZIP_DIRECTORY_MIN_SIZE (1024 * 1024)
struct zip_local_header {
unsigned char magic[4];
unsigned char version[2];
unsigned char flags[2];
unsigned char compression_method[2];
unsigned char mtime[2];
unsigned char mdate[2];
unsigned char crc32[4];
unsigned char compressed_size[4];
unsigned char size[4];
unsigned char filename_length[2];
unsigned char extra_length[2];
};
struct zip_dir_header {
unsigned char magic[4];
unsigned char creator_version[2];
unsigned char version[2];
unsigned char flags[2];
unsigned char compression_method[2];
unsigned char mtime[2];
unsigned char mdate[2];
unsigned char crc32[4];
unsigned char compressed_size[4];
unsigned char size[4];
unsigned char filename_length[2];
unsigned char extra_length[2];
unsigned char comment_length[2];
unsigned char disk[2];
unsigned char attr1[2];
unsigned char attr2[4];
unsigned char offset[4];
};
struct zip_dir_trailer {
unsigned char magic[4];
unsigned char disk[2];
unsigned char directory_start_disk[2];
unsigned char entries_on_this_disk[2];
unsigned char entries[2];
unsigned char size[4];
unsigned char offset[4];
unsigned char comment_length[2];
};
static void copy_le16(unsigned char *dest, unsigned int n)
{
dest[0] = 0xff & n;
dest[1] = 0xff & (n >> 010);
}
static void copy_le32(unsigned char *dest, unsigned int n)
{
dest[0] = 0xff & n;
dest[1] = 0xff & (n >> 010);
dest[2] = 0xff & (n >> 020);
dest[3] = 0xff & (n >> 030);
}
static void *zlib_deflate(void *data, unsigned long size,
unsigned long *compressed_size)
{
z_stream stream;
unsigned long maxsize;
void *buffer;
int result;
memset(&stream, 0, sizeof(stream));
deflateInit(&stream, zlib_compression_level);
maxsize = deflateBound(&stream, size);
buffer = xmalloc(maxsize);
stream.next_in = data;
stream.avail_in = size;
stream.next_out = buffer;
stream.avail_out = maxsize;
do {
result = deflate(&stream, Z_FINISH);
} while (result == Z_OK);
if (result != Z_STREAM_END) {
free(buffer);
return NULL;
}
deflateEnd(&stream);
*compressed_size = stream.total_out;
return buffer;
}
static char *construct_path(const char *base, int baselen,
const char *filename, int isdir, int *pathlen)
{
int filenamelen = strlen(filename);
int len = baselen + filenamelen;
char *path, *p;
if (isdir)
len++;
p = path = xmalloc(len + 1);
memcpy(p, base, baselen);
p += baselen;
memcpy(p, filename, filenamelen);
p += filenamelen;
if (isdir)
*p++ = '/';
*p = '\0';
*pathlen = len;
return path;
}
static int write_zip_entry(const unsigned char *sha1,
const char *base, int baselen,
const char *filename, unsigned mode, int stage)
{
struct zip_local_header header;
struct zip_dir_header dirent;
unsigned long compressed_size;
unsigned long uncompressed_size;
unsigned long crc;
unsigned long direntsize;
unsigned long size;
int method;
int result = -1;
int pathlen;
unsigned char *out;
char *path;
char type[20];
void *buffer = NULL;
void *deflated = NULL;
crc = crc32(0, Z_NULL, 0);
path = construct_path(base, baselen, filename, S_ISDIR(mode), &pathlen);
if (pathlen > 0xffff) {
error("path too long (%d chars, SHA1: %s): %s", pathlen,
sha1_to_hex(sha1), path);
goto out;
}
if (S_ISDIR(mode)) {
method = 0;
result = READ_TREE_RECURSIVE;
out = NULL;
uncompressed_size = 0;
compressed_size = 0;
} else if (S_ISREG(mode)) {
method = zlib_compression_level == 0 ? 0 : 8;
result = 0;
buffer = read_sha1_file(sha1, type, &size);
if (!buffer)
die("cannot read %s", sha1_to_hex(sha1));
crc = crc32(crc, buffer, size);
out = buffer;
uncompressed_size = size;
compressed_size = size;
} else {
error("unsupported file mode: 0%o (SHA1: %s)", mode,
sha1_to_hex(sha1));
goto out;
}
if (method == 8) {
deflated = zlib_deflate(buffer, size, &compressed_size);
if (deflated && compressed_size - 6 < size) {
/* ZLIB --> raw compressed data (see RFC 1950) */
/* CMF and FLG ... */
out = (unsigned char *)deflated + 2;
compressed_size -= 6; /* ... and ADLER32 */
} else {
method = 0;
compressed_size = size;
}
}
/* make sure we have enough free space in the dictionary */
direntsize = sizeof(struct zip_dir_header) + pathlen;
while (zip_dir_size < zip_dir_offset + direntsize) {
zip_dir_size += ZIP_DIRECTORY_MIN_SIZE;
zip_dir = xrealloc(zip_dir, zip_dir_size);
}
copy_le32(dirent.magic, 0x02014b50);
copy_le16(dirent.creator_version, 0);
copy_le16(dirent.version, 20);
copy_le16(dirent.flags, 0);
copy_le16(dirent.compression_method, method);
copy_le16(dirent.mtime, zip_time);
copy_le16(dirent.mdate, zip_date);
copy_le32(dirent.crc32, crc);
copy_le32(dirent.compressed_size, compressed_size);
copy_le32(dirent.size, uncompressed_size);
copy_le16(dirent.filename_length, pathlen);
copy_le16(dirent.extra_length, 0);
copy_le16(dirent.comment_length, 0);
copy_le16(dirent.disk, 0);
copy_le16(dirent.attr1, 0);
copy_le32(dirent.attr2, 0);
copy_le32(dirent.offset, zip_offset);
memcpy(zip_dir + zip_dir_offset, &dirent, sizeof(struct zip_dir_header));
zip_dir_offset += sizeof(struct zip_dir_header);
memcpy(zip_dir + zip_dir_offset, path, pathlen);
zip_dir_offset += pathlen;
zip_dir_entries++;
copy_le32(header.magic, 0x04034b50);
copy_le16(header.version, 20);
copy_le16(header.flags, 0);
copy_le16(header.compression_method, method);
copy_le16(header.mtime, zip_time);
copy_le16(header.mdate, zip_date);
copy_le32(header.crc32, crc);
copy_le32(header.compressed_size, compressed_size);
copy_le32(header.size, uncompressed_size);
copy_le16(header.filename_length, pathlen);
copy_le16(header.extra_length, 0);
write_or_die(1, &header, sizeof(struct zip_local_header));
zip_offset += sizeof(struct zip_local_header);
write_or_die(1, path, pathlen);
zip_offset += pathlen;
if (compressed_size > 0) {
write_or_die(1, out, compressed_size);
zip_offset += compressed_size;
}
out:
free(buffer);
free(deflated);
free(path);
return result;
}
static void write_zip_trailer(const unsigned char *sha1)
{
struct zip_dir_trailer trailer;
copy_le32(trailer.magic, 0x06054b50);
copy_le16(trailer.disk, 0);
copy_le16(trailer.directory_start_disk, 0);
copy_le16(trailer.entries_on_this_disk, zip_dir_entries);
copy_le16(trailer.entries, zip_dir_entries);
copy_le32(trailer.size, zip_dir_offset);
copy_le32(trailer.offset, zip_offset);
copy_le16(trailer.comment_length, sha1 ? 40 : 0);
write_or_die(1, zip_dir, zip_dir_offset);
write_or_die(1, &trailer, sizeof(struct zip_dir_trailer));
if (sha1)
write_or_die(1, sha1_to_hex(sha1), 40);
}
static void dos_time(time_t *time, int *dos_date, int *dos_time)
{
struct tm *t = localtime(time);
*dos_date = t->tm_mday + (t->tm_mon + 1) * 32 +
(t->tm_year + 1900 - 1980) * 512;
*dos_time = t->tm_sec / 2 + t->tm_min * 32 + t->tm_hour * 2048;
}
int cmd_zip_tree(int argc, const char **argv, const char *prefix)
{
unsigned char sha1[20];
struct tree *tree;
struct commit *commit;
time_t archive_time;
char *base;
int baselen;
git_config(git_default_config);
if (argc > 1 && argv[1][0] == '-') {
if (isdigit(argv[1][1]) && argv[1][2] == '\0') {
zlib_compression_level = argv[1][1] - '0';
argc--;
argv++;
}
}
switch (argc) {
case 3:
base = strdup(argv[2]);
baselen = strlen(base);
break;
case 2:
base = strdup("");
baselen = 0;
break;
default:
usage(zip_tree_usage);
}
if (get_sha1(argv[1], sha1))
die("Not a valid object name %s", argv[1]);
commit = lookup_commit_reference_gently(sha1, 1);
archive_time = commit ? commit->date : time(NULL);
dos_time(&archive_time, &zip_date, &zip_time);
zip_dir = xmalloc(ZIP_DIRECTORY_MIN_SIZE);
zip_dir_size = ZIP_DIRECTORY_MIN_SIZE;
tree = parse_tree_indirect(sha1);
if (!tree)
die("not a tree object");
if (baselen > 0) {
write_zip_entry(tree->object.sha1, "", 0, base, 040777, 0);
base = xrealloc(base, baselen + 1);
base[baselen] = '/';
baselen++;
base[baselen] = '\0';
}
read_tree_recursive(tree, base, baselen, 0, NULL, write_zip_entry);
write_zip_trailer(commit ? commit->object.sha1 : NULL);
free(zip_dir);
free(base);
return 0;
}
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