zlib: wrap inflateInit2 used to accept only for gzip format

http-backend.c uses inflateInit2() to tell the library that it wants to
accept only gzip format. Wrap it in a helper function so that readers do
not have to wonder what the magic numbers 15 and 16 are for.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/cache.h b/cache.h
index ce73e1f09d7fc4f4196e32c2cfdd16e343ad9653..50f09d05d4596ec62179444c0b8165254ebee5c5 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -21,6 +21,7 @@
 #endif
 
 void git_inflate_init(z_streamp strm);
+void git_inflate_init_gzip_only(z_streamp strm);
 void git_inflate_end(z_streamp strm);
 int git_inflate(z_streamp strm, int flush);
 

diff --git a/http-backend.c b/http-backend.c
index c74cb03a705f4e61c46c7cdb29f507ff12bab27e..ab5015d9d90cdbc5ac6126090e7b5a1cbf0bd626 100644 (file)
--- a/http-backend.c
+++ b/http-backend.c
@@ -275,12 +275,9 @@ static void inflate_request(const char *prog_name, int out)
        unsigned char in_buf[8192];
        unsigned char out_buf[8192];
        unsigned long cnt = 0;
-       int ret;
 
        memset(&stream, 0, sizeof(stream));
-       ret = inflateInit2(&stream, (15 + 16));
-       if (ret != Z_OK)
-               die("cannot start zlib inflater, zlib err %d", ret);
+       git_inflate_init_gzip_only(&stream);
 
        while (1) {
                ssize_t n = xread(0, in_buf, sizeof(in_buf));

diff --git a/zlib.c b/zlib.c
index be9d7e963b88ac20cf4639de9dd4ddaaf3ff7a80..b613cbd75085384df2ec87fcf2475f7d154f55ff 100644 (file)
--- a/zlib.c
+++ b/zlib.c
@@ -32,6 +32,21 @@ void git_inflate_init(z_streamp strm)
            strm->msg ? strm->msg : "no message");
 }
 
+void git_inflate_init_gzip_only(z_streamp 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 = inflateInit2(strm, windowBits);
+
+       if (status == Z_OK)
+               return;
+       die("inflateInit2: %s (%s)", zerr_to_string(status),
+           strm->msg ? strm->msg : "no message");
+}
+
 void git_inflate_end(z_streamp strm)
 {
        int status = inflateEnd(strm);