git-tar-tree: Move code for git-archive --format=tar to archive-tar.c

This patch doesn't change any functionality, it only moves code around.  It
makes seeing the few remaining lines of git-tar-tree code easier. ;-)

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

1 files changed, 325 insertions, 0 deletions

diff --git a/archive-tar.c b/archive-tar.c
new file mode 100644
index 0000000000..ff0f6e2929
--- /dev/null
+++ b/archive-tar.c
@@ -0,0 +1,325 @@
+/*
+ * Copyright (c) 2005, 2006 Rene Scharfe
+ */
+#include <time.h>
+#include "cache.h"
+#include "commit.h"
+#include "strbuf.h"
+#include "tar.h"
+#include "builtin.h"
+#include "archive.h"
+
+#define RECORDSIZE	(512)
+#define BLOCKSIZE	(RECORDSIZE * 20)
+
+static char block[BLOCKSIZE];
+static unsigned long offset;
+
+static time_t archive_time;
+static int tar_umask;
+static int verbose;
+
+/* writes out the whole block, but only if it is full */
+static void write_if_needed(void)
+{
+	if (offset == BLOCKSIZE) {
+		write_or_die(1, block, BLOCKSIZE);
+		offset = 0;
+	}
+}
+
+/*
+ * queues up writes, so that all our write(2) calls write exactly one
+ * full block; pads writes to RECORDSIZE
+ */
+static void write_blocked(const void *data, unsigned long size)
+{
+	const char *buf = data;
+	unsigned long tail;
+
+	if (offset) {
+		unsigned long chunk = BLOCKSIZE - offset;
+		if (size < chunk)
+			chunk = size;
+		memcpy(block + offset, buf, chunk);
+		size -= chunk;
+		offset += chunk;
+		buf += chunk;
+		write_if_needed();
+	}
+	while (size >= BLOCKSIZE) {
+		write_or_die(1, buf, BLOCKSIZE);
+		size -= BLOCKSIZE;
+		buf += BLOCKSIZE;
+	}
+	if (size) {
+		memcpy(block + offset, buf, size);
+		offset += size;
+	}
+	tail = offset % RECORDSIZE;
+	if (tail)  {
+		memset(block + offset, 0, RECORDSIZE - tail);
+		offset += RECORDSIZE - tail;
+	}
+	write_if_needed();
+}
+
+/*
+ * The end of tar archives is marked by 2*512 nul bytes and after that
+ * follows the rest of the block (if any).
+ */
+static void write_trailer(void)
+{
+	int tail = BLOCKSIZE - offset;
+	memset(block + offset, 0, tail);
+	write_or_die(1, block, BLOCKSIZE);
+	if (tail < 2 * RECORDSIZE) {
+		memset(block, 0, offset);
+		write_or_die(1, block, BLOCKSIZE);
+	}
+}
+
+static void strbuf_append_string(struct strbuf *sb, const char *s)
+{
+	int slen = strlen(s);
+	int total = sb->len + slen;
+	if (total > sb->alloc) {
+		sb->buf = xrealloc(sb->buf, total);
+		sb->alloc = total;
+	}
+	memcpy(sb->buf + sb->len, s, slen);
+	sb->len = total;
+}
+
+/*
+ * pax extended header records have the format "%u %s=%s\n".  %u contains
+ * the size of the whole string (including the %u), the first %s is the
+ * keyword, the second one is the value.  This function constructs such a
+ * string and appends it to a struct strbuf.
+ */
+static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
+                                     const char *value, unsigned int valuelen)
+{
+	char *p;
+	int len, total, tmp;
+
+	/* "%u %s=%s\n" */
+	len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
+	for (tmp = len; tmp > 9; tmp /= 10)
+		len++;
+
+	total = sb->len + len;
+	if (total > sb->alloc) {
+		sb->buf = xrealloc(sb->buf, total);
+		sb->alloc = total;
+	}
+
+	p = sb->buf;
+	p += sprintf(p, "%u %s=", len, keyword);
+	memcpy(p, value, valuelen);
+	p += valuelen;
+	*p = '\n';
+	sb->len = total;
+}
+
+static unsigned int ustar_header_chksum(const struct ustar_header *header)
+{
+	char *p = (char *)header;
+	unsigned int chksum = 0;
+	while (p < header->chksum)
+		chksum += *p++;
+	chksum += sizeof(header->chksum) * ' ';
+	p += sizeof(header->chksum);
+	while (p < (char *)header + sizeof(struct ustar_header))
+		chksum += *p++;
+	return chksum;
+}
+
+static int get_path_prefix(const struct strbuf *path, int maxlen)
+{
+	int i = path->len;
+	if (i > maxlen)
+		i = maxlen;
+	do {
+		i--;
+	} while (i > 0 && path->buf[i] != '/');
+	return i;
+}
+
+static void write_entry(const unsigned char *sha1, struct strbuf *path,
+                        unsigned int mode, void *buffer, unsigned long size)
+{
+	struct ustar_header header;
+	struct strbuf ext_header;
+
+	memset(&header, 0, sizeof(header));
+	ext_header.buf = NULL;
+	ext_header.len = ext_header.alloc = 0;
+
+	if (!sha1) {
+		*header.typeflag = TYPEFLAG_GLOBAL_HEADER;
+		mode = 0100666;
+		strcpy(header.name, "pax_global_header");
+	} else if (!path) {
+		*header.typeflag = TYPEFLAG_EXT_HEADER;
+		mode = 0100666;
+		sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
+	} else {
+		if (verbose)
+			fprintf(stderr, "%.*s\n", path->len, path->buf);
+		if (S_ISDIR(mode)) {
+			*header.typeflag = TYPEFLAG_DIR;
+			mode = (mode | 0777) & ~tar_umask;
+		} else if (S_ISLNK(mode)) {
+			*header.typeflag = TYPEFLAG_LNK;
+			mode |= 0777;
+		} else if (S_ISREG(mode)) {
+			*header.typeflag = TYPEFLAG_REG;
+			mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
+		} else {
+			error("unsupported file mode: 0%o (SHA1: %s)",
+			      mode, sha1_to_hex(sha1));
+			return;
+		}
+		if (path->len > sizeof(header.name)) {
+			int plen = get_path_prefix(path, sizeof(header.prefix));
+			int rest = path->len - plen - 1;
+			if (plen > 0 && rest <= sizeof(header.name)) {
+				memcpy(header.prefix, path->buf, plen);
+				memcpy(header.name, path->buf + plen + 1, rest);
+			} else {
+				sprintf(header.name, "%s.data",
+				        sha1_to_hex(sha1));
+				strbuf_append_ext_header(&ext_header, "path",
+				                         path->buf, path->len);
+			}
+		} else
+			memcpy(header.name, path->buf, path->len);
+	}
+
+	if (S_ISLNK(mode) && buffer) {
+		if (size > sizeof(header.linkname)) {
+			sprintf(header.linkname, "see %s.paxheader",
+			        sha1_to_hex(sha1));
+			strbuf_append_ext_header(&ext_header, "linkpath",
+			                         buffer, size);
+		} else
+			memcpy(header.linkname, buffer, size);
+	}
+
+	sprintf(header.mode, "%07o", mode & 07777);
+	sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
+	sprintf(header.mtime, "%011lo", archive_time);
+
+	/* XXX: should we provide more meaningful info here? */
+	sprintf(header.uid, "%07o", 0);
+	sprintf(header.gid, "%07o", 0);
+	strlcpy(header.uname, "git", sizeof(header.uname));
+	strlcpy(header.gname, "git", sizeof(header.gname));
+	sprintf(header.devmajor, "%07o", 0);
+	sprintf(header.devminor, "%07o", 0);
+
+	memcpy(header.magic, "ustar", 6);
+	memcpy(header.version, "00", 2);
+
+	sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
+
+	if (ext_header.len > 0) {
+		write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
+		free(ext_header.buf);
+	}
+	write_blocked(&header, sizeof(header));
+	if (S_ISREG(mode) && buffer && size > 0)
+		write_blocked(buffer, size);
+}
+
+static void write_global_extended_header(const unsigned char *sha1)
+{
+	struct strbuf ext_header;
+	ext_header.buf = NULL;
+	ext_header.len = ext_header.alloc = 0;
+	strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
+	write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
+	free(ext_header.buf);
+}
+
+static int git_tar_config(const char *var, const char *value)
+{
+	if (!strcmp(var, "tar.umask")) {
+		if (!strcmp(value, "user")) {
+			tar_umask = umask(0);
+			umask(tar_umask);
+		} else {
+			tar_umask = git_config_int(var, value);
+		}
+		return 0;
+	}
+	return git_default_config(var, value);
+}
+
+static int write_tar_entry(const unsigned char *sha1,
+                           const char *base, int baselen,
+                           const char *filename, unsigned mode, int stage)
+{
+	static struct strbuf path;
+	int filenamelen = strlen(filename);
+	void *buffer;
+	char type[20];
+	unsigned long size;
+
+	if (!path.alloc) {
+		path.buf = xmalloc(PATH_MAX);
+		path.alloc = PATH_MAX;
+		path.len = path.eof = 0;
+	}
+	if (path.alloc < baselen + filenamelen) {
+		free(path.buf);
+		path.buf = xmalloc(baselen + filenamelen);
+		path.alloc = baselen + filenamelen;
+	}
+	memcpy(path.buf, base, baselen);
+	memcpy(path.buf + baselen, filename, filenamelen);
+	path.len = baselen + filenamelen;
+	if (S_ISDIR(mode)) {
+		strbuf_append_string(&path, "/");
+		buffer = NULL;
+		size = 0;
+	} else {
+		buffer = read_sha1_file(sha1, type, &size);
+		if (!buffer)
+			die("cannot read %s", sha1_to_hex(sha1));
+	}
+
+	write_entry(sha1, &path, mode, buffer, size);
+	free(buffer);
+
+	return READ_TREE_RECURSIVE;
+}
+
+int write_tar_archive(struct archiver_args *args)
+{
+	int plen = args->base ? strlen(args->base) : 0;
+
+	git_config(git_tar_config);
+
+	archive_time = args->time;
+	verbose = args->verbose;
+
+	if (args->commit_sha1)
+		write_global_extended_header(args->commit_sha1);
+
+	if (args->base && plen > 0 && args->base[plen - 1] == '/') {
+		char *base = xstrdup(args->base);
+		int baselen = strlen(base);
+
+		while (baselen > 0 && base[baselen - 1] == '/')
+			base[--baselen] = '\0';
+		write_tar_entry(args->tree->object.sha1, "", 0, base, 040777, 0);
+		free(base);
+	}
+	read_tree_recursive(args->tree, args->base, plen, 0,
+			    args->pathspec, write_tar_entry);
+	write_trailer();
+
+	return 0;
+}