gzip: fix concatenated gzip payload handling.

The implementation of flb_gzip_count is flawed as it relies on looking
for valid gzip headers. A gzip payload can be generated that includes
a valid gzip header in the gzip body - see test_header_in_gzip_body.

Removed flb_gzip_count and associated handling in favor of utilizing
mz_inflate to find the boundaries between concatenated gzip payloads
during decompression. mz_inflate will stop when it reaches the end of
the gzip body and mz_stream.in_avail contains the bytes left in the
buffer for processing.

Signed-off-by: Brandon Strub <[email protected]>

Author: Brandon Strub

include/fluent-bit/flb_gzip.h

@@ -31,13 +31,19 @@ int flb_gzip_compress(void *in_data, size_t in_len,
 int flb_gzip_uncompress(void *in_data, size_t in_len,
                         void **out_data, size_t *out_size);
 
+/*
+ * Uncompress a gzip payload with trailing data. On success in_remaining is set to the number
+ * of input bits not part of the first gzip payload.
+ */
+int flb_gzip_uncompress_multi(void *in_data, size_t in_len,
+                        void **out_data, size_t *out_size, size_t *in_remaining);
+
 void *flb_gzip_decompression_context_create();
 void flb_gzip_decompression_context_destroy(void *context);
 
 int flb_gzip_decompressor_dispatch(struct flb_decompression_context *context,
                                    void *out_data, size_t *out_size);
 
 int flb_is_http_session_gzip_compressed(struct mk_http_session *session);
-size_t flb_gzip_count(const char *data, size_t len, size_t **out_borders, size_t border_count);
 
 #endif