Removing instances of exec_ctx being passed around in functions in

src/core. exec_ctx is now a thread_local pointer of type ExecCtx instead of
grpc_exec_ctx which is initialized whenever ExecCtx is instantiated. ExecCtx
also keeps track of the previous exec_ctx so that nesting of exec_ctx is
allowed. This means that there is only one exec_ctx being used at any
time. Also, grpc_exec_ctx_finish is called in the destructor of the
object, and the previous exec_ctx is restored to avoid breaking current
functionality. The code still explicitly calls grpc_exec_ctx_finish
because removing all such instances causes the code to break.

1 files changed, 9 insertions, 13 deletions

diff --git a/src/core/lib/security/credentials/iam/iam_credentials.cc b/src/core/lib/security/credentials/iam/iam_credentials.cc
index e9cf208c16..3b91e739f1 100644
--- a/src/core/lib/security/credentials/iam/iam_credentials.cc
+++ b/src/core/lib/security/credentials/iam/iam_credentials.cc
@@ -27,14 +27,12 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/sync.h>
 
-static void iam_destruct(grpc_exec_ctx *exec_ctx,
-                         grpc_call_credentials *creds) {
+static void iam_destruct(grpc_call_credentials *creds) {
   grpc_google_iam_credentials *c = (grpc_google_iam_credentials *)creds;
-  grpc_credentials_mdelem_array_destroy(exec_ctx, &c->md_array);
+  grpc_credentials_mdelem_array_destroy(&c->md_array);
 }
 
-static bool iam_get_request_metadata(grpc_exec_ctx *exec_ctx,
-                                     grpc_call_credentials *creds,
+static bool iam_get_request_metadata(grpc_call_credentials *creds,
                                      grpc_polling_entity *pollent,
                                      grpc_auth_metadata_context context,
                                      grpc_credentials_mdelem_array *md_array,
@@ -46,8 +44,8 @@ static bool iam_get_request_metadata(grpc_exec_ctx *exec_ctx,
 }
 
 static void iam_cancel_get_request_metadata(
-    grpc_exec_ctx *exec_ctx, grpc_call_credentials *c,
-    grpc_credentials_mdelem_array *md_array, grpc_error *error) {
+    grpc_call_credentials *c, grpc_credentials_mdelem_array *md_array,
+    grpc_error *error) {
   GRPC_ERROR_UNREF(error);
 }
 
@@ -56,7 +54,7 @@ static grpc_call_credentials_vtable iam_vtable = {
 
 grpc_call_credentials *grpc_google_iam_credentials_create(
     const char *token, const char *authority_selector, void *reserved) {
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  ExecCtx _local_exec_ctx;
   GRPC_API_TRACE(
       "grpc_iam_credentials_create(token=%s, authority_selector=%s, "
       "reserved=%p)",
@@ -70,17 +68,15 @@ grpc_call_credentials *grpc_google_iam_credentials_create(
   c->base.vtable = &iam_vtable;
   gpr_ref_init(&c->base.refcount, 1);
   grpc_mdelem md = grpc_mdelem_from_slices(
-      &exec_ctx,
       grpc_slice_from_static_string(GRPC_IAM_AUTHORIZATION_TOKEN_METADATA_KEY),
       grpc_slice_from_copied_string(token));
   grpc_credentials_mdelem_array_add(&c->md_array, md);
-  GRPC_MDELEM_UNREF(&exec_ctx, md);
+  GRPC_MDELEM_UNREF(md);
   md = grpc_mdelem_from_slices(
-      &exec_ctx,
       grpc_slice_from_static_string(GRPC_IAM_AUTHORITY_SELECTOR_METADATA_KEY),
       grpc_slice_from_copied_string(authority_selector));
   grpc_credentials_mdelem_array_add(&c->md_array, md);
-  GRPC_MDELEM_UNREF(&exec_ctx, md);
-  grpc_exec_ctx_finish(&exec_ctx);
+  GRPC_MDELEM_UNREF(md);
+  grpc_exec_ctx_finish();
   return &c->base;
 }