add test

src/core/lib/iomgr/tcp_posix.cc

@@ -576,8 +576,8 @@ static bool tcp_flush(grpc_exec_ctx* exec_ctx, grpc_tcp* tcp,
       if (errno == EAGAIN) {
         tcp->outgoing_slice_idx = unwind_slice_idx;
         tcp->outgoing_byte_idx = unwind_byte_idx;
-        grpc_slice_buffer_partial_reset_and_unref_internal(
+        grpc_slice_buffer_partial_unref_internal(exec_ctx, tcp->outgoing_buffer,
-            exec_ctx, tcp->outgoing_buffer, unwind_slice_idx);
+                                                 unwind_slice_idx);
         return false;
       } else if (errno == EPIPE) {
         *error = grpc_error_set_int(GRPC_OS_ERROR(errno, "sendmsg"),

src/core/lib/slice/slice_buffer.cc

@@ -176,10 +176,11 @@ void grpc_slice_buffer_reset_and_unref_internal(grpc_exec_ctx* exec_ctx,
   sb->idx_of_first_valid_slice = 0;
 }
 
-void grpc_slice_buffer_partial_reset_and_unref_internal(grpc_exec_ctx* exec_ctx,
+void grpc_slice_buffer_partial_unref_internal(grpc_exec_ctx* exec_ctx,
                                               grpc_slice_buffer* sb,
                                               size_t idx) {
-  GPR_ASSERT(idx <= sb->count);
+  GPR_ASSERT(idx < sb->count);  //  if idx == count, then partial is not needed
+  GPR_ASSERT(sb->idx_of_first_valid_slice <= idx);
 
   size_t i;
   for (i = sb->idx_of_first_valid_slice; i < idx; i++) {

src/core/lib/slice/slice_internal.h

@@ -32,7 +32,7 @@ grpc_slice grpc_slice_ref_internal(grpc_slice slice);
 void grpc_slice_unref_internal(grpc_exec_ctx* exec_ctx, grpc_slice slice);
 void grpc_slice_buffer_reset_and_unref_internal(grpc_exec_ctx* exec_ctx,
                                                 grpc_slice_buffer* sb);
-void grpc_slice_buffer_partial_reset_and_unref_internal(grpc_exec_ctx* exec_ctx,
+void grpc_slice_buffer_partial_unref_internal(grpc_exec_ctx* exec_ctx,
                                               grpc_slice_buffer* sb,
                                               size_t idx);
 void grpc_slice_buffer_destroy_internal(grpc_exec_ctx* exec_ctx,

test/core/slice/slice_buffer_test.cc

@@ -18,6 +18,7 @@
 
 #include <grpc/slice_buffer.h>
 #include <grpc/support/log.h>
+#include "src/core/lib/slice/slice_internal.h"
 #include "test/core/util/test_config.h"
 
 void test_slice_buffer_add() {
@@ -104,11 +105,49 @@ void test_slice_buffer_move_first() {
   GPR_ASSERT(dst.length == dst_len);
 }
 
+static void populate_slice_buffer(grpc_slice_buffer* sb) {
+  grpc_slice slices[4];
+  int idx = 0;
+
+  slices[0] = grpc_slice_from_copied_string("aaa");
+  slices[1] = grpc_slice_from_copied_string("bbbb");
+  slices[2] = grpc_slice_from_copied_string("ccc");
+  slices[3] = grpc_slice_from_copied_string("ddddd");
+
+  for (idx = 0; idx < 4; idx++) {
+    grpc_slice_ref(slices[idx]);
+    grpc_slice_buffer_add_indexed(sb, slices[idx]);
+  }
+}
+
+void test_slice_buffer_unref() {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_slice_buffer sb;
+
+  grpc_slice_buffer_init(&sb);
+
+  // regular init and unref
+  populate_slice_buffer(&sb);
+  grpc_slice_buffer_reset_and_unref_internal(&exec_ctx, &sb);
+
+  // inits, then unrefs partial, then unrefs the rest
+  populate_slice_buffer(&sb);
+  grpc_slice_buffer_partial_unref_internal(&exec_ctx, &sb, 1);
+  grpc_slice_buffer_reset_and_unref_internal(&exec_ctx, &sb);
+
+  // two partial unrefs
+  populate_slice_buffer(&sb);
+  grpc_slice_buffer_partial_unref_internal(&exec_ctx, &sb, 1);
+  grpc_slice_buffer_partial_unref_internal(&exec_ctx, &sb, 3);
+  grpc_slice_buffer_reset_and_unref_internal(&exec_ctx, &sb);
+}
+
 int main(int argc, char** argv) {
   grpc_test_init(argc, argv);
 
   test_slice_buffer_add();
   test_slice_buffer_move_first();
+  test_slice_buffer_unref();
 
   return 0;
 }