Make "write_sha1_file()" exit early if the file already exists.

Avoid the compression.

diff --git a/sha1_file.c b/sha1_file.c
index 40c00b7..eee3598 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -173,12 +173,30 @@ int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
        z_stream stream;
        unsigned char sha1[20];
        SHA_CTX c;
+       char *filename;
+       int fd;
 
        /* Sha1.. */
        SHA1_Init(&c);
        SHA1_Update(&c, buf, len);
        SHA1_Final(sha1, &c);
 
+       if (returnsha1)
+               memcpy(returnsha1, sha1, 20);
+
+       filename = sha1_file_name(sha1);
+       fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
+       if (fd < 0) {
+               if (errno != EEXIST)
+                       return -1;
+
+               /*
+                * We might do collision checking here, but we'd need to
+                * uncompress the old file and check it. Later.
+                */
+               return 0;
+       }
+
        /* Set it up */
        memset(&stream, 0, sizeof(stream));
        deflateInit(&stream, Z_BEST_COMPRESSION);
@@ -195,10 +213,10 @@ int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
        deflateEnd(&stream);
        size = stream.total_out;
 
-       if (write_sha1_buffer(sha1, compressed, size) < 0)
-               return -1;
-       if (returnsha1)
-               memcpy(returnsha1, sha1, 20);
+       if (write(fd, compressed, size) != size)
+               die("unable to write file");
+       close(fd);
+               
        return 0;
 }