Not sure to understand, a temporary HandleScope already exists in my code:
// Create a stack-allocated handle scope
v8::HandleScope handle_scope(instance->engine->isolate);
// Enter the context for compiling and running the script
v8::Local<v8::Context>
context(instance->context->Get(instance->engine->isolate));
v8::Context::Scope context_scope(context);
On Monday, November 2, 2020 at 11:17:32 AM UTC+1 szu...@google.com wrote:
> My guess is that in your V8ContextCreate function you also need a
> temporary HandleScope before you can make a global out of the context:
>
> v8::HandleScope handle_scope(engine->isolate);
>
> On Mon, Nov 2, 2020 at 10:36 AM Marco Bambini <marco....@gmail.com> wrote:
>
>> Dear All,
>> I am a C developer quite new to v8 (I have limited c++ knowledge).
>> Sorry if I ask very basic questions.
>>
>> I have a C application that need to execute some js code in different
>> times preserving the same context.
>>
>> My code looks like:
>> *Header file*
>> *=========*
>> #ifdef __cplusplus
>> extern "C" {
>> #endif
>> #include <stdbool.h>
>>
>> typedef struct V8Engine V8Engine;
>> typedef struct V8Context V8Context;
>> typedef struct V8Value V8Value;
>>
>> V8Engine* V8EngineInit (const char *path);
>> void V8EngineFree (V8Engine *engine);
>> V8Context* V8ContextCreate (V8Engine *engine);
>> void V8ContextFree (V8Context *context);
>> V8Value* V8ExecuteScript (V8Context *context, const char *script);
>> bool V8ValueIsError (V8Value *value);
>>
>> #ifdef __cplusplus
>>
>> }
>>
>> #endif
>>
>> #endif
>>
>>
>>
>> *C++ file*
>> *======*
>> #include "libplatform/libplatform.h"
>> #include "v8.h"
>> #include "c8.h"
>>
>> struct V8Engine {
>> std::unique_ptr<v8::Platform> platform;
>> v8::Isolate::CreateParams create_params;
>> v8::Isolate *isolate;
>> v8::Isolate::Scope *isolate_scope;
>>
>> };
>>
>> struct V8Context {
>> V8Engine *engine;
>> v8::Global<v8::Context> *context;
>> };
>>
>> struct V8Value {
>>
>> };
>>
>>
>>
>> // MARK: -
>>
>> extern "C" {
>>
>> V8Engine* V8EngineInit (const char *path) {
>> V8Engine *engine = (V8Engine *)calloc(1, sizeof(V8Engine));
>> if (!engine) return nullptr;
>>
>> // Initialize V8
>> v8::V8::InitializeICUDefaultLocation(path);
>> v8::V8::InitializeExternalStartupData(path);
>> engine->platform = v8::platform::NewDefaultPlatform();
>>
>> v8::V8::InitializePlatform(engine->platform.get());
>> v8::V8::Initialize();
>>
>> engine->create_params.array_buffer_allocator =
>> v8::ArrayBuffer::Allocator::NewDefaultAllocator();
>> engine->isolate = v8::Isolate::New(engine->create_params);
>> engine->isolate_scope = new v8::Isolate::Scope(engine->isolate);
>>
>> return engine;
>> }
>>
>>
>> void V8EngineFree (V8Engine *engine) {
>> if (engine == NULL) return;
>>
>> if (engine->isolate_scope) {
>> delete engine->isolate_scope;
>> }
>>
>> if (engine->isolate) {
>> engine->isolate->Dispose();
>> }
>>
>> v8::V8::Dispose();
>> v8::V8::ShutdownPlatform();
>>
>> if (engine->create_params.array_buffer_allocator) {
>> delete engine->create_params.array_buffer_allocator;
>> }
>>
>> engine->~V8Engine();
>> free(engine);
>> }
>>
>>
>>
>> V8Context* V8ContextCreate (V8Engine *engine) {
>> V8Context *instance = (V8Context *)calloc(1, sizeof(V8Context));
>> if (!instance) return nullptr;
>>
>> instance->engine = engine;
>> v8::Local<v8::Context> local_context =
>> v8::Context::New(engine->isolate);
>> instance->context = new v8::Global<v8::Context>(engine->isolate,
>> local_context);
>>
>> return instance;
>> }
>>
>> void V8ContextFree (V8Context *context) {
>> delete context->context;
>> context->~V8Context();
>> free(context);
>> }
>>
>>
>>
>> V8Value* V8ExecuteScript (V8Context *instance, const char *script) {
>> // Create a stack-allocated handle scope
>> v8::HandleScope handle_scope(instance->engine->isolate);
>>
>> // Enter the context for compiling and running the script
>> v8::Local<v8::Context>
>> context(instance->context->Get(instance->engine->isolate));
>> v8::Context::Scope context_scope(context);
>>
>> {
>> // Create a string containing the JavaScript source code
>> v8::Local<v8::String> source =
>> v8::String::NewFromUtf8(instance->engine->isolate, script,
>> v8::NewStringType::kNormal).ToLocalChecked();
>>
>> // Compile the source code
>> v8::Local<v8::Script> script = v8::Script::Compile(context,
>> source).ToLocalChecked();
>>
>> // Run the script to get the result
>> v8::Local<v8::Value> result =
>> script->Run(context).ToLocalChecked();
>>
>> // Convert the result to an UTF8 string and print it
>> v8::String::Utf8Value utf8(instance->engine->isolate, result);
>> printf("%s\n", *utf8);
>> }
>>
>> return nullptr;
>> }
>>
>>
>>
>> bool V8ValueIsError (V8Value *value) {
>> return false;
>> }
>>
>> }
>>
>> *// main C file*
>> *==========*
>> int main (int argc, char* argv[]) {
>> V8Engine *vm = V8EngineInit(argv[0]);
>> V8Context *context = V8ContextCreate(vm);
>>
>> const char *script1 = " function js_add_elements(var1, var2) { \
>> var var3 = parseInt(var1) +
>> parseInt(var2); \
>> var result = 'Addition of ' + var1 + '
>> and ' + var2 + ' results ' + var3; \
>> return result; \
>> };";
>> const char *script2 = "js_add_elements(2, 3);";
>> const char *script3 = "js_add_elements(4, 5);";
>>
>> V8ExecuteScript(context, script1);
>> V8ExecuteScript(context, script2);
>> V8ExecuteScript(context, script3);
>>
>> V8ContextFree(context);
>> V8EngineFree(vm);
>> }
>>
>> When I run this code this error is printed on console:
>>
>> *#*
>> *# Fatal error in v8::HandleScope::CreateHandle()*
>> *# Cannot create a handle without a HandleScope*
>> *#*
>>
>> on the line
>> v8::Local<v8::Context> local_context = v8::Context::New(engine->isolate);
>>
>> in
>> V8Context* V8ContextCreate (V8Engine *engine)
>>
>> Please let me know what I am doing wrong (a fixed sample code would be
>> extremely useful).
>>
>> Thanks a lot,
>> Marco Bambini
>>
>> --
>> --
>> v8-users mailing list
>> v8-u...@googlegroups.com
>> http://groups.google.com/group/v8-users
>> ---
>> You received this message because you are subscribed to the Google Groups
>> "v8-users" group.
>> To unsubscribe from this group and stop receiving emails from it, send an
>> email to v8-users+u...@googlegroups.com.
>> To view this discussion on the web visit
>> https://groups.google.com/d/msgid/v8-users/9da40893-5c6c-402b-89a8-d9a3ce617555n%40googlegroups.com
>>
>> <https://groups.google.com/d/msgid/v8-users/9da40893-5c6c-402b-89a8-d9a3ce617555n%40googlegroups.com?utm_medium=email&utm_source=footer>
>> .
>>
>
--
--
v8-users mailing list
v8-users@googlegroups.com
http://groups.google.com/group/v8-users
---
You received this message because you are subscribed to the Google Groups
"v8-users" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to v8-users+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/v8-users/802372d9-b86b-4229-97b3-97cc12495837n%40googlegroups.com.
