git-archive --format=zip: add symlink support

Add symlink support to ZIP file creation, and a few tests.

This implementation sets the "version made by" field
(creator_version) to Unix for symlinks, only; regular files and
directories are still marked as originating from FAT/VFAT/NTFS.

Also set "external file attributes" (attr2) to 0 for regular
files and 16 for directories (FAT attribute), and to the file
mode for symlinks.

We could always set the creator_version to Unix and include the
mode, but then Info-ZIP unzip would set the mode of the extracted
files to *exactly* the value stored in attr2.  The FAT trick
makes it apply the umask instead.  Note: FAT has no executable
bit, so this information is not stored in the ZIP file.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <junkio@cox.net>

archive-zip.c

@@ -145,6 +145,7 @@ static int write_zip_entry(const unsigned char *sha1,
 {
 	struct zip_local_header header;
 	struct zip_dir_header dirent;
+	unsigned long attr2;
 	unsigned long compressed_size;
 	unsigned long uncompressed_size;
 	unsigned long crc;
@@ -172,12 +173,16 @@ static int write_zip_entry(const unsigned char *sha1,
 
 	if (S_ISDIR(mode)) {
 		method = 0;
+		attr2 = 16;
 		result = READ_TREE_RECURSIVE;
 		out = NULL;
 		uncompressed_size = 0;
 		compressed_size = 0;
-	} else if (S_ISREG(mode)) {
-		method = zlib_compression_level == 0 ? 0 : 8;
+	} else if (S_ISREG(mode) || S_ISLNK(mode)) {
+		method = 0;
+		attr2 = S_ISLNK(mode) ? ((mode | 0777) << 16) : 0;
+		if (S_ISREG(mode) && zlib_compression_level != 0)
+			method = 8;
 		result = 0;
 		buffer = read_sha1_file(sha1, type, &size);
 		if (!buffer)
@@ -213,7 +218,7 @@ static int write_zip_entry(const unsigned char *sha1,
 	}
 
 	copy_le32(dirent.magic, 0x02014b50);
-	copy_le16(dirent.creator_version, 0);
+	copy_le16(dirent.creator_version, S_ISLNK(mode) ? 0x0317 : 0);
 	copy_le16(dirent.version, 10);
 	copy_le16(dirent.flags, 0);
 	copy_le16(dirent.compression_method, method);
@@ -227,7 +232,7 @@ static int write_zip_entry(const unsigned char *sha1,
 	copy_le16(dirent.comment_length, 0);
 	copy_le16(dirent.disk, 0);
 	copy_le16(dirent.attr1, 0);
-	copy_le32(dirent.attr2, 0);
+	copy_le32(dirent.attr2, attr2);
 	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);

t/t5000-tar-tree.sh

@@ -26,6 +26,7 @@ commit id embedding:
 
 . ./test-lib.sh
 TAR=${TAR:-tar}
+UNZIP=${UNZIP:-unzip}
 
 test_expect_success \
     'populate workdir' \
@@ -95,4 +96,38 @@ test_expect_success \
     'validate file contents with prefix' \
     'diff -r a c/prefix/a'
 
+test_expect_success \
+    'git-archive --format=zip' \
+    'git-archive --format=zip HEAD >d.zip'
+
+test_expect_success \
+    'extract ZIP archive' \
+    '(mkdir d && cd d && $UNZIP ../d.zip)'
+
+test_expect_success \
+    'validate filenames' \
+    '(cd d/a && find .) | sort >d.lst &&
+     diff a.lst d.lst'
+
+test_expect_success \
+    'validate file contents' \
+    'diff -r a d/a'
+
+test_expect_success \
+    'git-archive --format=zip with prefix' \
+    'git-archive --format=zip --prefix=prefix/ HEAD >e.zip'
+
+test_expect_success \
+    'extract ZIP archive with prefix' \
+    '(mkdir e && cd e && $UNZIP ../e.zip)'
+
+test_expect_success \
+    'validate filenames with prefix' \
+    '(cd e/prefix/a && find .) | sort >e.lst &&
+     diff a.lst e.lst'
+
+test_expect_success \
+    'validate file contents with prefix' \
+    'diff -r a e/prefix/a'
+
 test_done