1 files changed, 217 insertions, 0 deletions
diff --git a/core/libdeno/exceptions.cc b/core/libdeno/exceptions.cc
new file mode 100644
index 000000000..85f0ca340
--- /dev/null
+++ b/core/libdeno/exceptions.cc
@@ -0,0 +1,217 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+#include "exceptions.h"
+#include <string>
+
+namespace deno {
+
+v8::Local<v8::Object> EncodeMessageAsObject(v8::Local<v8::Context> context,
+                                            v8::Local<v8::Message> message) {
+  auto* isolate = context->GetIsolate();
+  v8::EscapableHandleScope handle_scope(isolate);
+  v8::Context::Scope context_scope(context);
+
+  auto stack_trace = message->GetStackTrace();
+
+  // Encode the exception into a JS object, which we will then turn into JSON.
+  auto json_obj = v8::Object::New(isolate);
+  auto exception_str = message->Get();
+  CHECK(json_obj->Set(context, v8_str("message"), exception_str).FromJust());
+
+  auto maybe_source_line = message->GetSourceLine(context);
+  if (!maybe_source_line.IsEmpty()) {
+    CHECK(json_obj
+              ->Set(context, v8_str("sourceLine"),
+                    maybe_source_line.ToLocalChecked())
+              .FromJust());
+  }
+
+  CHECK(json_obj
+            ->Set(context, v8_str("scriptResourceName"),
+                  message->GetScriptResourceName())
+            .FromJust());
+
+  auto maybe_line_number = message->GetLineNumber(context);
+  if (maybe_line_number.IsJust()) {
+    CHECK(json_obj
+              ->Set(context, v8_str("lineNumber"),
+                    v8::Integer::New(isolate, maybe_line_number.FromJust()))
+              .FromJust());
+  }
+
+  CHECK(json_obj
+            ->Set(context, v8_str("startPosition"),
+                  v8::Integer::New(isolate, message->GetStartPosition()))
+            .FromJust());
+
+  CHECK(json_obj
+            ->Set(context, v8_str("endPosition"),
+                  v8::Integer::New(isolate, message->GetEndPosition()))
+            .FromJust());
+
+  CHECK(json_obj
+            ->Set(context, v8_str("errorLevel"),
+                  v8::Integer::New(isolate, message->ErrorLevel()))
+            .FromJust());
+
+  auto maybe_start_column = message->GetStartColumn(context);
+  if (maybe_start_column.IsJust()) {
+    auto start_column =
+        v8::Integer::New(isolate, maybe_start_column.FromJust());
+    CHECK(
+        json_obj->Set(context, v8_str("startColumn"), start_column).FromJust());
+  }
+
+  auto maybe_end_column = message->GetEndColumn(context);
+  if (maybe_end_column.IsJust()) {
+    auto end_column = v8::Integer::New(isolate, maybe_end_column.FromJust());
+    CHECK(json_obj->Set(context, v8_str("endColumn"), end_column).FromJust());
+  }
+
+  CHECK(json_obj
+            ->Set(context, v8_str("isSharedCrossOrigin"),
+                  v8::Boolean::New(isolate, message->IsSharedCrossOrigin()))
+            .FromJust());
+
+  CHECK(json_obj
+            ->Set(context, v8_str("isOpaque"),
+                  v8::Boolean::New(isolate, message->IsOpaque()))
+            .FromJust());
+
+  v8::Local<v8::Array> frames;
+  if (!stack_trace.IsEmpty()) {
+    uint32_t count = static_cast<uint32_t>(stack_trace->GetFrameCount());
+    frames = v8::Array::New(isolate, count);
+
+    for (uint32_t i = 0; i < count; ++i) {
+      auto frame = stack_trace->GetFrame(isolate, i);
+      auto frame_obj = v8::Object::New(isolate);
+      CHECK(frames->Set(context, i, frame_obj).FromJust());
+      auto line = v8::Integer::New(isolate, frame->GetLineNumber());
+      auto column = v8::Integer::New(isolate, frame->GetColumn());
+      CHECK(frame_obj->Set(context, v8_str("line"), line).FromJust());
+      CHECK(frame_obj->Set(context, v8_str("column"), column).FromJust());
+      CHECK(frame_obj
+                ->Set(context, v8_str("functionName"), frame->GetFunctionName())
+                .FromJust());
+      // scriptName can be empty in special conditions e.g. eval
+      auto scriptName = frame->GetScriptNameOrSourceURL();
+      if (scriptName.IsEmpty()) {
+        scriptName = v8_str("<unknown>");
+      }
+      CHECK(
+          frame_obj->Set(context, v8_str("scriptName"), scriptName).FromJust());
+      CHECK(frame_obj
+                ->Set(context, v8_str("isEval"),
+                      v8::Boolean::New(isolate, frame->IsEval()))
+                .FromJust());
+      CHECK(frame_obj
+                ->Set(context, v8_str("isConstructor"),
+                      v8::Boolean::New(isolate, frame->IsConstructor()))
+                .FromJust());
+      CHECK(frame_obj
+                ->Set(context, v8_str("isWasm"),
+                      v8::Boolean::New(isolate, frame->IsWasm()))
+                .FromJust());
+    }
+  } else {
+    // No stack trace. We only have one stack frame of info..
+    frames = v8::Array::New(isolate, 1);
+
+    auto frame_obj = v8::Object::New(isolate);
+    CHECK(frames->Set(context, 0, frame_obj).FromJust());
+
+    auto line =
+        v8::Integer::New(isolate, message->GetLineNumber(context).FromJust());
+    auto column =
+        v8::Integer::New(isolate, message->GetStartColumn(context).FromJust());
+
+    CHECK(frame_obj->Set(context, v8_str("line"), line).FromJust());
+    CHECK(frame_obj->Set(context, v8_str("column"), column).FromJust());
+    CHECK(frame_obj
+              ->Set(context, v8_str("scriptName"),
+                    message->GetScriptResourceName())
+              .FromJust());
+  }
+
+  CHECK(json_obj->Set(context, v8_str("frames"), frames).FromJust());
+  json_obj = handle_scope.Escape(json_obj);
+  return json_obj;
+}
+
+std::string EncodeMessageAsJSON(v8::Local<v8::Context> context,
+                                v8::Local<v8::Message> message) {
+  auto* isolate = context->GetIsolate();
+  v8::HandleScope handle_scope(isolate);
+  v8::Context::Scope context_scope(context);
+  auto json_obj = EncodeMessageAsObject(context, message);
+  auto json_string = v8::JSON::Stringify(context, json_obj).ToLocalChecked();
+  v8::String::Utf8Value json_string_(isolate, json_string);
+  return std::string(ToCString(json_string_));
+}
+
+v8::Local<v8::Object> EncodeExceptionAsObject(v8::Local<v8::Context> context,
+                                              v8::Local<v8::Value> exception) {
+  auto* isolate = context->GetIsolate();
+  v8::EscapableHandleScope handle_scope(isolate);
+  v8::Context::Scope context_scope(context);
+
+  auto message = v8::Exception::CreateMessage(isolate, exception);
+  auto json_obj = EncodeMessageAsObject(context, message);
+  json_obj = handle_scope.Escape(json_obj);
+  return json_obj;
+}
+
+std::string EncodeExceptionAsJSON(v8::Local<v8::Context> context,
+                                  v8::Local<v8::Value> exception) {
+  auto* isolate = context->GetIsolate();
+  v8::HandleScope handle_scope(isolate);
+  v8::Context::Scope context_scope(context);
+
+  auto message = v8::Exception::CreateMessage(isolate, exception);
+  return EncodeMessageAsJSON(context, message);
+}
+
+void HandleException(v8::Local<v8::Context> context,
+                     v8::Local<v8::Value> exception) {
+  v8::Isolate* isolate = context->GetIsolate();
+
+  // TerminateExecution was called
+  if (isolate->IsExecutionTerminating()) {
+    // cancel exception termination so that the exception can be created
+    isolate->CancelTerminateExecution();
+
+    // maybe make a new exception object
+    if (exception->IsNullOrUndefined()) {
+      exception = v8::Exception::Error(v8_str("execution terminated"));
+    }
+
+    // handle the exception as if it is a regular exception
+    HandleException(context, exception);
+
+    // re-enable exception termination
+    isolate->TerminateExecution();
+    return;
+  }
+
+  DenoIsolate* d = DenoIsolate::FromIsolate(isolate);
+  std::string json_str = EncodeExceptionAsJSON(context, exception);
+  CHECK_NOT_NULL(d);
+  d->last_exception_ = json_str;
+}
+
+void HandleExceptionMessage(v8::Local<v8::Context> context,
+                            v8::Local<v8::Message> message) {
+  v8::Isolate* isolate = context->GetIsolate();
+
+  // TerminateExecution was called
+  if (isolate->IsExecutionTerminating()) {
+    HandleException(context, v8::Undefined(isolate));
+    return;
+  }
+
+  DenoIsolate* d = DenoIsolate::FromIsolate(isolate);
+  std::string json_str = EncodeMessageAsJSON(context, message);
+  CHECK_NOT_NULL(d);
+  d->last_exception_ = json_str;
+}
+}  // namespace deno