1 files changed, 271 insertions, 0 deletions
diff --git a/zlib.c b/zlib.c
new file mode 100644
index 0000000000..61e6df0fdc
--- /dev/null
+++ b/zlib.c
@@ -0,0 +1,271 @@
+/*
+ * zlib wrappers to make sure we don't silently miss errors
+ * at init time.
+ */
+#include "cache.h"
+
+static const char *zerr_to_string(int status)
+{
+	switch (status) {
+	case Z_MEM_ERROR:
+		return "out of memory";
+	case Z_VERSION_ERROR:
+		return "wrong version";
+	case Z_NEED_DICT:
+		return "needs dictionary";
+	case Z_DATA_ERROR:
+		return "data stream error";
+	case Z_STREAM_ERROR:
+		return "stream consistency error";
+	default:
+		return "unknown error";
+	}
+}
+
+/*
+ * avail_in and avail_out in zlib are counted in uInt, which typically
+ * limits the size of the buffer we can use to 4GB when interacting
+ * with zlib in a single call to inflate/deflate.
+ */
+/* #define ZLIB_BUF_MAX ((uInt)-1) */
+#define ZLIB_BUF_MAX ((uInt) 1024 * 1024 * 1024) /* 1GB */
+static inline uInt zlib_buf_cap(unsigned long len)
+{
+	return (ZLIB_BUF_MAX < len) ? ZLIB_BUF_MAX : len;
+}
+
+static void zlib_pre_call(git_zstream *s)
+{
+	s->z.next_in = s->next_in;
+	s->z.next_out = s->next_out;
+	s->z.total_in = s->total_in;
+	s->z.total_out = s->total_out;
+	s->z.avail_in = zlib_buf_cap(s->avail_in);
+	s->z.avail_out = zlib_buf_cap(s->avail_out);
+}
+
+static void zlib_post_call(git_zstream *s)
+{
+	unsigned long bytes_consumed;
+	unsigned long bytes_produced;
+
+	bytes_consumed = s->z.next_in - s->next_in;
+	bytes_produced = s->z.next_out - s->next_out;
+	if (s->z.total_out != s->total_out + bytes_produced)
+		die("BUG: total_out mismatch");
+	if (s->z.total_in != s->total_in + bytes_consumed)
+		die("BUG: total_in mismatch");
+
+	s->total_out = s->z.total_out;
+	s->total_in = s->z.total_in;
+	s->next_in = s->z.next_in;
+	s->next_out = s->z.next_out;
+	s->avail_in -= bytes_consumed;
+	s->avail_out -= bytes_produced;
+}
+
+void git_inflate_init(git_zstream *strm)
+{
+	int status;
+
+	zlib_pre_call(strm);
+	status = inflateInit(&strm->z);
+	zlib_post_call(strm);
+	if (status == Z_OK)
+		return;
+	die("inflateInit: %s (%s)", zerr_to_string(status),
+	    strm->z.msg ? strm->z.msg : "no message");
+}
+
+void git_inflate_init_gzip_only(git_zstream *strm)
+{
+	/*
+	 * Use default 15 bits, +16 is to accept only gzip and to
+	 * yield Z_DATA_ERROR when fed zlib format.
+	 */
+	const int windowBits = 15 + 16;
+	int status;
+
+	zlib_pre_call(strm);
+	status = inflateInit2(&strm->z, windowBits);
+	zlib_post_call(strm);
+	if (status == Z_OK)
+		return;
+	die("inflateInit2: %s (%s)", zerr_to_string(status),
+	    strm->z.msg ? strm->z.msg : "no message");
+}
+
+void git_inflate_end(git_zstream *strm)
+{
+	int status;
+
+	zlib_pre_call(strm);
+	status = inflateEnd(&strm->z);
+	zlib_post_call(strm);
+	if (status == Z_OK)
+		return;
+	error("inflateEnd: %s (%s)", zerr_to_string(status),
+	      strm->z.msg ? strm->z.msg : "no message");
+}
+
+int git_inflate(git_zstream *strm, int flush)
+{
+	int status;
+
+	for (;;) {
+		zlib_pre_call(strm);
+		/* Never say Z_FINISH unless we are feeding everything */
+		status = inflate(&strm->z,
+				 (strm->z.avail_in != strm->avail_in)
+				 ? 0 : flush);
+		if (status == Z_MEM_ERROR)
+			die("inflate: out of memory");
+		zlib_post_call(strm);
+
+		/*
+		 * Let zlib work another round, while we can still
+		 * make progress.
+		 */
+		if ((strm->avail_out && !strm->z.avail_out) &&
+		    (status == Z_OK || status == Z_BUF_ERROR))
+			continue;
+		break;
+	}
+
+	switch (status) {
+	/* Z_BUF_ERROR: normal, needs more space in the output buffer */
+	case Z_BUF_ERROR:
+	case Z_OK:
+	case Z_STREAM_END:
+		return status;
+	default:
+		break;
+	}
+	error("inflate: %s (%s)", zerr_to_string(status),
+	      strm->z.msg ? strm->z.msg : "no message");
+	return status;
+}
+
+#if defined(NO_DEFLATE_BOUND) || ZLIB_VERNUM < 0x1200
+#define deflateBound(c,s)  ((s) + (((s) + 7) >> 3) + (((s) + 63) >> 6) + 11)
+#endif
+
+unsigned long git_deflate_bound(git_zstream *strm, unsigned long size)
+{
+	return deflateBound(&strm->z, size);
+}
+
+void git_deflate_init(git_zstream *strm, int level)
+{
+	int status;
+
+	zlib_pre_call(strm);
+	status = deflateInit(&strm->z, level);
+	zlib_post_call(strm);
+	if (status == Z_OK)
+		return;
+	die("deflateInit: %s (%s)", zerr_to_string(status),
+	    strm->z.msg ? strm->z.msg : "no message");
+}
+
+static void do_git_deflate_init(git_zstream *strm, int level, int windowBits)
+{
+	int status;
+
+	zlib_pre_call(strm);
+	status = deflateInit2(&strm->z, level,
+				  Z_DEFLATED, windowBits,
+				  8, Z_DEFAULT_STRATEGY);
+	zlib_post_call(strm);
+	if (status == Z_OK)
+		return;
+	die("deflateInit2: %s (%s)", zerr_to_string(status),
+	    strm->z.msg ? strm->z.msg : "no message");
+}
+
+void git_deflate_init_gzip(git_zstream *strm, int level)
+{
+	/*
+	 * Use default 15 bits, +16 is to generate gzip header/trailer
+	 * instead of the zlib wrapper.
+	 */
+	do_git_deflate_init(strm, level, 15 + 16);
+}
+
+void git_deflate_init_raw(git_zstream *strm, int level)
+{
+	/*
+	 * Use default 15 bits, negate the value to get raw compressed
+	 * data without zlib header and trailer.
+	 */
+	do_git_deflate_init(strm, level, -15);
+}
+
+int git_deflate_abort(git_zstream *strm)
+{
+	int status;
+
+	zlib_pre_call(strm);
+	status = deflateEnd(&strm->z);
+	zlib_post_call(strm);
+	return status;
+}
+
+void git_deflate_end(git_zstream *strm)
+{
+	int status = git_deflate_abort(strm);
+
+	if (status == Z_OK)
+		return;
+	error("deflateEnd: %s (%s)", zerr_to_string(status),
+	      strm->z.msg ? strm->z.msg : "no message");
+}
+
+int git_deflate_end_gently(git_zstream *strm)
+{
+	int status;
+
+	zlib_pre_call(strm);
+	status = deflateEnd(&strm->z);
+	zlib_post_call(strm);
+	return status;
+}
+
+int git_deflate(git_zstream *strm, int flush)
+{
+	int status;
+
+	for (;;) {
+		zlib_pre_call(strm);
+
+		/* Never say Z_FINISH unless we are feeding everything */
+		status = deflate(&strm->z,
+				 (strm->z.avail_in != strm->avail_in)
+				 ? 0 : flush);
+		if (status == Z_MEM_ERROR)
+			die("deflate: out of memory");
+		zlib_post_call(strm);
+
+		/*
+		 * Let zlib work another round, while we can still
+		 * make progress.
+		 */
+		if ((strm->avail_out && !strm->z.avail_out) &&
+		    (status == Z_OK || status == Z_BUF_ERROR))
+			continue;
+		break;
+	}
+
+	switch (status) {
+	/* Z_BUF_ERROR: normal, needs more space in the output buffer */
+	case Z_BUF_ERROR:
+	case Z_OK:
+	case Z_STREAM_END:
+		return status;
+	default:
+		break;
+	}
+	error("deflate: %s (%s)", zerr_to_string(status),
+	      strm->z.msg ? strm->z.msg : "no message");
+	return status;
+}