lib-dcrypt: istream-decrypt - Add support for getting stream size

diff --git a/src/lib-dcrypt/istream-decrypt.c b/src/lib-dcrypt/istream-decrypt.c
index d94e804a2e5496ab9860dbde380fa6d85c915ffe..d3f47277c7b19649cf69b68d691d81744b454d41 100644 (file)
--- a/src/lib-dcrypt/istream-decrypt.c
+++ b/src/lib-dcrypt/istream-decrypt.c
@@ -40,6 +40,10 @@ struct decrypt_istream {
        struct dcrypt_context_hmac *ctx_mac;
 
        enum decrypt_istream_format format;
+
+       /* Initially (uoff_t)-1. Otherwise it's the exact known stream size,
+          which can be used by stat() / get_size(). */
+       uoff_t cached_stream_size;
 };
 
 static void i_stream_decrypt_reset(struct decrypt_istream *dstream)
@@ -855,6 +859,47 @@ i_stream_decrypt_seek(struct istream_private *stream, uoff_t v_offset,
                i_unreached();
 }
 
+static int
+seekable_i_stream_get_size(struct istream_private *stream)
+{
+       struct decrypt_istream *dstream =
+               (struct decrypt_istream *)stream;
+
+       if (dstream->cached_stream_size == (uoff_t)-1) {
+               uoff_t old_offset = stream->istream.v_offset;
+               ssize_t ret;
+
+               do {
+                       i_stream_skip(&stream->istream,
+                                     i_stream_get_data_size(&stream->istream));
+               } while ((ret = i_stream_read(&stream->istream)) > 0);
+               i_assert(ret == -1);
+               if (stream->istream.stream_errno != 0)
+                       return -1;
+
+               dstream->cached_stream_size = stream->istream.v_offset;
+               i_stream_seek(&stream->istream, old_offset);
+       }
+       stream->statbuf.st_size = dstream->cached_stream_size;
+       return 0;
+}
+
+static int i_stream_decrypt_stat(struct istream_private *stream, bool exact)
+{
+       const struct stat *st;
+
+       if (i_stream_stat(stream->parent, exact, &st) < 0) {
+               stream->istream.stream_errno = stream->parent->stream_errno;
+               return -1;
+       }
+       stream->statbuf = *st;
+       if (exact) {
+               if (seekable_i_stream_get_size(stream) < 0)
+                       return -1;
+       }
+       return 0;
+}
+
 static
 void i_stream_decrypt_close(struct iostream_private *stream,
                                   bool close_parent)
@@ -894,8 +939,10 @@ struct decrypt_istream *i_stream_create_decrypt_common(struct istream *input)
        dstream = i_new(struct decrypt_istream, 1);
        dstream->istream.max_buffer_size = input->real_stream->max_buffer_size;
        dstream->istream.read = i_stream_decrypt_read;
-       if (input->seekable)
+       if (input->seekable) {
                dstream->istream.seek = i_stream_decrypt_seek;
+               dstream->istream.stat = i_stream_decrypt_stat;
+       }
        dstream->istream.iostream.close = i_stream_decrypt_close;
        dstream->istream.iostream.destroy = i_stream_decrypt_destroy;
 
@@ -904,6 +951,7 @@ struct decrypt_istream *i_stream_create_decrypt_common(struct istream *input)
        dstream->istream.istream.seekable = input->seekable;
 
        dstream->buf = buffer_create_dynamic(default_pool, 512);
+       dstream->cached_stream_size = (uoff_t)-1;
 
        (void)i_stream_create(&dstream->istream, input,
                              i_stream_get_fd(input));