From fbff7054a47551387a99244e2cf0631f30406798 Mon Sep 17 00:00:00 2001

From: Trevor Norris <trev.norris@gmail.com>

Date: Tue, 18 Nov 2014 16:37:54 -0800

Subject: [PATCH] v8: add api for aborting on uncaught exception

Add v8::Isolate::SetAbortOnUncaughtException() so the user can be

notified when an uncaught exception has bubbled.

PR-URL: https://github.com/joyent/node/pull/8666

Reviewed-by: Trevor Norris <trev.norris@gmail.com>

---

 include/v8.h   | 11 +++++++++++

 src/api.cc     |  5 +++++

 src/isolate.cc | 33 +++++++++++++++++++++++----------

 src/isolate.h  |  5 +++++

 4 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/include/v8.h b/include/v8.h

index 71a0d01..e229ed9 100644

--- a/include/v8.h

+++ b/include/v8.h

@@ -2842,6 +2842,17 @@ class V8EXPORT Isolate {

   static Isolate* GetCurrent();

   /**

+   * Custom callback used by embedders to help V8 determine if it should abort

+   * when it throws and no internal handler can catch the exception.

+   * If FLAG_abort_on_uncaught_exception is true, then V8 will abort if either:

+   * - no custom callback is set.

+   * - the custom callback set returns true.

+   * Otherwise it won't abort.

+   */

+  typedef bool (*abort_on_uncaught_exception_t)();

+  void SetAbortOnUncaughtException(abort_on_uncaught_exception_t callback);

+

+  /**

    * Methods below this point require holding a lock (using Locker) in

    * a multi-threaded environment.

    */

diff --git a/src/api.cc b/src/api.cc

index 96d564f..4b1aa67 100644

--- a/src/api.cc

+++ b/src/api.cc

@@ -5550,6 +5550,11 @@ void Isolate::Enter() {

   isolate->Enter();

 }

+void Isolate::SetAbortOnUncaughtException(

+      abort_on_uncaught_exception_t callback) {

+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);

+  isolate->SetAbortOnUncaughtException(callback);

+}

 void Isolate::Exit() {

   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);

diff --git a/src/isolate.cc b/src/isolate.cc

index 5a5293e..0b38616 100644

--- a/src/isolate.cc

+++ b/src/isolate.cc

@@ -1152,18 +1152,26 @@ void Isolate::DoThrow(Object* exception, MessageLocation* location) {

         thread_local_top()->pending_message_end_pos_ = location->end_pos();

       }

-      // If the abort-on-uncaught-exception flag is specified, abort on any

-      // exception not caught by JavaScript, even when an external handler is

-      // present.  This flag is intended for use by JavaScript developers, so

-      // print a user-friendly stack trace (not an internal one).

+      // If the abort-on-uncaught-exception flag is specified, and if the

+      // exception is not caught by JavaScript (even when an external handler is

+      // present).

       if (fatal_exception_depth == 0 &&

           FLAG_abort_on_uncaught_exception &&

           (report_exception || can_be_caught_externally)) {

-        fatal_exception_depth++;

-        fprintf(stderr, "%s\n\nFROM\n",

-          *MessageHandler::GetLocalizedMessage(message_obj));

-        PrintCurrentStackTrace(stderr);

-        OS::Abort();

+        // If the embedder didn't specify a custom uncaught exception callback,

+        // or if the custom callback determined that V8 should abort, then

+        // abort

+        bool should_abort = !abort_on_uncaught_exception_callback_ ||

+                             abort_on_uncaught_exception_callback_();

+        if (should_abort) {

+          fatal_exception_depth++;

+          // This flag is intended for use by JavaScript developers, so

+          // print a user-friendly stack trace (not an internal one).

+          fprintf(stderr, "%s\n\nFROM\n",

+            *MessageHandler::GetLocalizedMessage(message_obj));

+          PrintCurrentStackTrace(stderr);

+          OS::Abort();

+        }

       }

     } else if (location != NULL && !location->script().is_null()) {

       // We are bootstrapping and caught an error where the location is set

@@ -1339,6 +1347,10 @@ void Isolate::SetCaptureStackTraceForUncaughtExceptions(

   stack_trace_for_uncaught_exceptions_options_ = options;

 }

+void Isolate::SetAbortOnUncaughtException(

+      v8::Isolate::abort_on_uncaught_exception_t callback) {

+  abort_on_uncaught_exception_callback_ = callback;

+}

 bool Isolate::is_out_of_memory() {

   if (has_pending_exception()) {

@@ -1534,7 +1546,8 @@ Isolate::Isolate()

       date_cache_(NULL),

       context_exit_happened_(false),

       deferred_handles_head_(NULL),

-      optimizing_compiler_thread_(this) {

+      optimizing_compiler_thread_(this),

+      abort_on_uncaught_exception_callback_(NULL) {

   TRACE_ISOLATE(constructor);

   memset(isolate_addresses_, 0,

diff --git a/src/isolate.h b/src/isolate.h

index 2769ca7..8719aa1 100644

--- a/src/isolate.h

+++ b/src/isolate.h

@@ -692,6 +692,9 @@ class Isolate {

       int frame_limit,

       StackTrace::StackTraceOptions options);

+  typedef bool (*abort_on_uncaught_exception_t)();

+  void SetAbortOnUncaughtException(abort_on_uncaught_exception_t callback);

+

   // Tells whether the current context has experienced an out of memory

   // exception.

   bool is_out_of_memory();

@@ -1292,6 +1295,8 @@ class Isolate {

   DeferredHandles* deferred_handles_head_;

   OptimizingCompilerThread optimizing_compiler_thread_;

+  abort_on_uncaught_exception_t abort_on_uncaught_exception_callback_;

+

   friend class ExecutionAccess;

   friend class HandleScopeImplementer;

   friend class IsolateInitializer;