Merge branch 'np/compress-loose-object-memsave'

* np/compress-loose-object-memsave:
sha1_file: be paranoid when creating loose objects
sha1_file: don't malloc the whole compressed result when writing out objects

diff --combined sha1_file.c
index 0375159604205cb1fe00adf7d33533224475a61d,c0214d794635e2046c20dee298c9c0db5dda8f91..006321e009b321db6cf4f7bf35d8385017a7076a
--- 1/sha1_file.c
--- 2/sha1_file.c
+++ b/sha1_file.c
@@@ -2281,9 -2281,10 +2281,10 @@@ static int write_loose_object(const uns
                              void *buf, unsigned long len, time_t mtime)
  {
        int fd, ret;
-       size_t size;
-       unsigned char *compressed;
+       unsigned char compressed[4096];
        z_stream stream;
+       git_SHA_CTX c;
+       unsigned char parano_sha1[20];
        char *filename;
        static char tmpfile[PATH_MAX];
  
@@@ -2301,36 -2302,40 +2302,40 @@@
        /* Set it up */
        memset(&stream, 0, sizeof(stream));
        deflateInit(&stream, zlib_compression_level);
-       size = 8 + deflateBound(&stream, len+hdrlen);
-       compressed = xmalloc(size);
- 
-       /* Compress it */
        stream.next_out = compressed;
-       stream.avail_out = size;
+       stream.avail_out = sizeof(compressed);
+       git_SHA1_Init(&c);
  
        /* First header.. */
        stream.next_in = (unsigned char *)hdr;
        stream.avail_in = hdrlen;
        while (deflate(&stream, 0) == Z_OK)
                /* nothing */;
+       git_SHA1_Update(&c, hdr, hdrlen);
  
        /* Then the data itself.. */
        stream.next_in = buf;
        stream.avail_in = len;
-       ret = deflate(&stream, Z_FINISH);
+       do {
+               unsigned char *in0 = stream.next_in;
+               ret = deflate(&stream, Z_FINISH);
+               git_SHA1_Update(&c, in0, stream.next_in - in0);
+               if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
+                       die("unable to write sha1 file");
+               stream.next_out = compressed;
+               stream.avail_out = sizeof(compressed);
+       } while (ret == Z_OK);
+ 
        if (ret != Z_STREAM_END)
                die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
- 
        ret = deflateEnd(&stream);
        if (ret != Z_OK)
                die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
+       git_SHA1_Final(parano_sha1, &c);
+       if (hashcmp(sha1, parano_sha1) != 0)
+               die("confused by unstable object source data for %s", sha1_to_hex(sha1));
  
-       size = stream.total_out;
- 
-       if (write_buffer(fd, compressed, size) < 0)
-               die("unable to write sha1 file");
        close_sha1_file(fd);
-       free(compressed);
  
        if (mtime) {
                struct utimbuf utb;
@@@ -2434,8 -2439,6 +2439,8 @@@ static int index_mem(unsigned char *sha
        return ret;
  }
  
 +#define SMALL_FILE_SIZE (32*1024)
 +
  int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
             enum object_type type, const char *path)
  {
@@@ -2450,14 -2453,6 +2455,14 @@@
                else
                        ret = -1;
                strbuf_release(&sbuf);
 +      } else if (size <= SMALL_FILE_SIZE) {
 +              char *buf = xmalloc(size);
 +              if (size == read_in_full(fd, buf, size))
 +                      ret = index_mem(sha1, buf, size, write_object, type,
 +                                      path);
 +              else
 +                      ret = error("short read %s", strerror(errno));
 +              free(buf);
        } else if (size) {
                void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
                ret = index_mem(sha1, buf, size, write_object, type, path);