journal: add dst_allocated_size parameter for compress_blob

compress_blob took src, src_size, dst and *dst_size, but dst_size
wasn't used as an input parameter with the size of dst, but only as an
output parameter. dst was implicitly assumed to be at least src_size-1.

This code wasn't *wrong*, because the only real caller in
journal-file.c got it right. But it was misleading, and the tests in
test-compress.c got it wrong, and worked only because the output
buffer happened to be the same size as input buffer. So add a seperate
dst_allocated_size parameter to make it explicit what the size of the
buffer is, and to allow test to proceed with different output buffer
sizes.

1 files changed, 8 insertions, 5 deletions

diff --git a/src/journal/compress.h b/src/journal/compress.h
index 9a065eb763..758598730a 100644
--- a/src/journal/compress.h
+++ b/src/journal/compress.h
@@ -28,17 +28,20 @@
 const char* object_compressed_to_string(int compression);
 int object_compressed_from_string(const char *compression);
 
-int compress_blob_xz(const void *src, uint64_t src_size, void *dst, size_t *dst_size);
-int compress_blob_lz4(const void *src, uint64_t src_size, void *dst, size_t *dst_size);
+int compress_blob_xz(const void *src, uint64_t src_size,
+                     void *dst, size_t dst_alloc_size, size_t *dst_size);
+int compress_blob_lz4(const void *src, uint64_t src_size,
+                      void *dst, size_t dst_alloc_size, size_t *dst_size);
 
-static inline int compress_blob(const void *src, uint64_t src_size, void *dst, size_t *dst_size) {
+static inline int compress_blob(const void *src, uint64_t src_size,
+                                void *dst, size_t dst_alloc_size, size_t *dst_size) {
         int r;
 #ifdef HAVE_LZ4
-        r = compress_blob_lz4(src, src_size, dst, dst_size);
+        r = compress_blob_lz4(src, src_size, dst, dst_alloc_size, dst_size);
         if (r == 0)
                 return OBJECT_COMPRESSED_LZ4;
 #else
-        r = compress_blob_xz(src, src_size, dst, dst_size);
+        r = compress_blob_xz(src, src_size, dst, dst_alloc_size, dst_size);
         if (r == 0)
                 return OBJECT_COMPRESSED_XZ;
 #endif