Comments and fixes

src/core/lib/compression/stream_compression.h

@@ -31,14 +31,15 @@ typedef struct grpc_stream_compression_context {
 } grpc_stream_compression_context;
 
 typedef enum grpc_stream_compression_method {
-  GRPC_STREAM_COMPRESSION_COMPRESS,
+  GRPC_STREAM_COMPRESSION_COMPRESS = 0,
   GRPC_STREAM_COMPRESSION_DECOMPRESS
 } grpc_stream_compression_method;
 
 typedef enum grpc_stream_compression_flush {
-  GRPC_STREAM_COMPRESSION_FLUSH_NONE,
+  GRPC_STREAM_COMPRESSION_FLUSH_NONE = 0,
   GRPC_STREAM_COMPRESSION_FLUSH_SYNC,
-  GRPC_STREAM_COMPRESSION_FLUSH_FINISH
+  GRPC_STREAM_COMPRESSION_FLUSH_FINISH,
+  GRPC_STREAM_COMPRESSION_FLUSH_COUNT
 } grpc_stream_compression_flush;
 
 /**
@@ -47,6 +48,12 @@ typedef enum grpc_stream_compression_flush {
  * into \a out. If all the bytes in input buffer \a in are depleted and \a flush
  * is not GRPC_STREAM_COMPRESSION_FLUSH_NONE, the corresponding flush method is
  * executed. The total number of bytes emitted is outputed in \a output_size.
+ *
+ * A SYNC flush indicates that the entire messages in \a in can be decompressed
+ * from \a out. A FINISH flush implies a SYNC flush, and that any further
+ * compression will not be dependent on the state of the current context and any
+ * previous compressed bytes. It allows corresponding decompression context to
+ * be dropped when reaching this boundary.
  */
 bool grpc_stream_compress(grpc_stream_compression_context *ctx,
                           grpc_slice_buffer *in, grpc_slice_buffer *out,

test/core/compression/stream_compression_test.c

@@ -72,7 +72,7 @@ static void test_stream_compression_simple_compress_decompress() {
   size_t output_size;
   GPR_ASSERT(grpc_stream_decompress(decompress_ctx, &relay, &sink, &output_size,
                                     ~(size_t)0, &end_of_context));
-  GPR_ASSERT(output_size = sizeof(test_str) - 1);
+  GPR_ASSERT(output_size == sizeof(test_str) - 1);
   grpc_stream_compression_context_destroy(compress_ctx);
   grpc_stream_compression_context_destroy(decompress_ctx);
 
@@ -107,7 +107,7 @@ test_stream_compression_simple_compress_decompress_with_output_size_constraint()
   size_t max_output_size = 2;
   GPR_ASSERT(grpc_stream_decompress(decompress_ctx, &relay, &sink, &output_size,
                                     max_output_size, &end_of_context));
-  GPR_ASSERT(output_size = max_output_size);
+  GPR_ASSERT(output_size == max_output_size);
   GPR_ASSERT(end_of_context == false);
   grpc_slice slice_recv = grpc_slice_buffer_take_first(&sink);
   char *str_recv = (char *)GRPC_SLICE_START_PTR(slice_recv);
@@ -118,8 +118,8 @@ test_stream_compression_simple_compress_decompress_with_output_size_constraint()
   size_t remaining_size = sizeof(test_str) - 1 - max_output_size;
   GPR_ASSERT(grpc_stream_decompress(decompress_ctx, &relay, &sink, &output_size,
                                     remaining_size, &end_of_context));
-  GPR_ASSERT(output_size = remaining_size);
-  GPR_ASSERT(end_of_context = true);
+  GPR_ASSERT(output_size == remaining_size);
+  GPR_ASSERT(end_of_context == true);
 
   GPR_ASSERT(slice_buffer_equals_string(&sink, test_str + max_output_size));
 
@@ -152,7 +152,7 @@ test_stream_compression_simple_compress_decompress_with_large_data() {
   size_t output_size;
   GPR_ASSERT(grpc_stream_decompress(decompress_ctx, &relay, &sink, &output_size,
                                     ~(size_t)0, &end_of_context));
-  GPR_ASSERT(output_size = sizeof(test_str) - 1);
+  GPR_ASSERT(output_size == sizeof(test_str) - 1);
   grpc_stream_compression_context_destroy(compress_ctx);
   grpc_stream_compression_context_destroy(decompress_ctx);