istream-hash: Data was hashed multiple times in some situations

diff --git a/src/lib/istream-hash.c b/src/lib/istream-hash.c
index b54c66bc0ee2577f46cdd61c4175f7f9e6167e2a..b64929c09f77153feac813629b78c2274f05980c 100644 (file)
--- a/src/lib/istream-hash.c
+++ b/src/lib/istream-hash.c
@@ -10,6 +10,7 @@ struct hash_istream {
 
        const struct hash_method *method;
        void *hash_context;
+       uoff_t high_offset;
 };
 
 static ssize_t
@@ -18,6 +19,7 @@ i_stream_hash_read(struct istream_private *stream)
        struct hash_istream *hstream = (struct hash_istream *)stream;
        const unsigned char *data;
        size_t size;
+       uoff_t skip;
        ssize_t ret;
 
        i_stream_seek(stream->parent, stream->parent_start_offset +
@@ -27,8 +29,14 @@ i_stream_hash_read(struct istream_private *stream)
        if (ret > 0 && hstream->hash_context != NULL) {
                data = i_stream_get_data(&stream->istream, &size);
                i_assert((size_t)ret <= size);
-               hstream->method->loop(hstream->hash_context,
-                                     data+(size-ret), ret);
+
+               i_assert(stream->istream.v_offset <= hstream->high_offset);
+               skip = hstream->high_offset - stream->istream.v_offset;
+               if (skip < (size_t)size) {
+                       hstream->high_offset += (size-skip);
+                       hstream->method->loop(hstream->hash_context,
+                                             data+skip, size-skip);
+               }
        } else if (ret < 0) {
                /* we finished hashing it. don't access it anymore, because
                   the memory pointed by the hash may be freed before the