I try it and got undefined at val_k , Any idea why ?
v8::Local<v8::Object> global_obj = m_Context->Global();
Local<Value> val_k = global_obj->Get(m_Context,
v8::String::NewFromUtf8(m_Isolate, "K")).ToLocalChecked();
I attached a file that reproduce it
Oren
On Thursday, July 2, 2020 at 5:22:39 PM UTC+3, Leszek Swirski wrote:
>
> I think you're misunderstanding the API.
>
> You have created a program which creates an object "K" in the global
> context, which you can access via the global object. So, you have to
> _first_ get the global object, _then_ get K from it, and only _then_ get
> the properties of K.
>
> So it'll be something like (haven't tested):
>
> // Get global object (effectively globalThis)
> v8::Local<v8::Object> global_obj = context->Global();
> // Get K from global object (effectively globalThis["K"])
> v8::Local<v8::Object> K_obj = global_obj->Get(context,
> v8::String::NewFromUtf8(isolate, "K"))
> // Get the properties from K (effectively Object.keys(globalThis["K"]))
> v8::Local<Array> arr = K_obj->GetPropertyNames(context);
>
>
> On Thu, Jul 2, 2020 at 4:01 PM <[email protected] <javascript:>> wrote:
>
>> What i"m doing wrong ?
>>
>> v8::Local<v8::Object> obj = m_Context->Global();
>>
>> 1) Local<Array> arr = obj->GetPropertyNames(m_Context).ToLocalChecked();
>> // I got arr->Length = 0
>> 2) Local<Array> arr= obj->GetPropertyNames(m_Context,
>> KeyCollectionMode::kIncludePrototypes, PropertyFilter::ALL_PROPERTIES,
>> IndexFilter::kSkipIndices).ToLocalChecked();
>> // i got 71 items , but none of them are mine
>>
>> 3) Local<Value> key =obj->Get(m_Context,
>> v8::String::NewFromUtf8(m_Isolate, "AA")).ToLocalChecked();
>> // i got undefined
>>
>> Thanks a lot for all your help
>> Oren
>>
>> On Thursday, July 2, 2020 at 2:57:35 PM UTC+3, Leszek Swirski wrote:
>>>
>>> You can access your K object via the context's global object
>>> <https://v8.github.io/api/head/classv8_1_1Context.html#af5cd9f97ef6a3307c1c21f80f4b743eb>,
>>>
>>> and then iterate it's properties from there.
>>>
>>> On Thu, Jul 2, 2020 at 1:47 PM <[email protected]> wrote:
>>>
>>>> i"m trying to get the variable from context / global without success.
>>>>
>>>> Any idea how to do it correctly?
>>>>
>>>>
>>>> On Wednesday, July 1, 2020 at 7:36:48 PM UTC+3, [email protected]
>>>> wrote:
>>>>>
>>>>> Thanks, I got you.
>>>>> Do you know how I retrieve objects from context?
>>>>>
>>>>> On Wednesday, July 1, 2020 at 1:31:54 PM UTC+3, Jakob Kummerow wrote:
>>>>>>
>>>>>> On Wed, Jul 1, 2020 at 12:13 PM <[email protected]> wrote:
>>>>>>
>>>>>>> Why do you say its global?
>>>>>>>
>>>>>>
>>>>>> After evaluating the string "const K = {...}", K is a global
>>>>>> variable in the provided context.
>>>>>>
>>>>>> At the sample code, I read the K object from a specific context.
>>>>>>
>>>>>>
>>>>>> No, that's not what you're doing. You're creating an object wrapper
>>>>>> around a string "K". That object creation needs a context, but that's
>>>>>> not
>>>>>> the same as reading a variable from that context.
>>>>>>
>>>>>> --
>>>> --
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>>>> To view this discussion on the web visit
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>>>>
>>>> <https://groups.google.com/d/msgid/v8-dev/c5187f07-6220-471b-958e-ab12f74bb614o%40googlegroups.com?utm_medium=email&utm_source=footer>
>>>> .
>>>>
>>> --
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>> .
>>
>
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// testv8.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include "v8.h"
#include "../include/libplatform/libplatform.h"
//#include "../src/objects/elements.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
using namespace v8;
using v8::TryCatch;
const char * exe_path = "C:\\v8\\bin\\"; // read from there icudtl.dat , natives_blob.bin , snapshot_blob.bin
//#define V8_COMPRESS_POINTERS
std::unique_ptr<v8::Platform> g_platform;
v8::Local<v8::Context> m_Context;
v8::Isolate * m_Isolate;
void InitializeV8(const char* exec_path)
{
V8::InitializeICUDefaultLocation(exec_path);
V8::InitializeExternalStartupData(exec_path);
g_platform = v8::platform::NewDefaultPlatform();
V8::InitializePlatform(g_platform.get());
V8::Initialize();
}
void UnInitializeV8()
{
v8::V8::Dispose();
v8::V8::ShutdownPlatform();
}
void Log(const char * error) {
OutputDebugStringA(error);
printf("Logged: %s\n", error);
}
void PrintValueAsString(const Handle<Value> key)
{
String::Utf8Value Str(m_Isolate, key);
OutputDebugStringA(std::string(*Str).c_str());
}
void checkProperty(Local<Value> val)
{
if (val->IsName()) {
v8::String::Utf8Value str(m_Isolate, val);
std::string cppStr(*str);
OutputDebugStringA(cppStr.c_str());
}
else if (val->IsStringObject()) {
v8::String::Utf8Value str(m_Isolate, val);
std::string cppStr(*str);
OutputDebugStringA(cppStr.c_str());
}
else if (val->IsNumberObject())
{
Maybe<double> db = val->NumberValue(m_Context);
}
else if (val->IsFunction())
{
Handle<v8::Function> func = v8::Handle<v8::Function>::Cast(val);
if (func.IsEmpty())
return;
}
else if (val->IsArray())
{
Handle<v8::Array> array = v8::Handle<v8::Array>::Cast(val);
int len = array->Length();
for (int i = 0; i < len; ++i)
{
const Handle<Value> key = array->Get(i);
checkProperty(key);
}
}
else if (val->IsObject())
{
bool a = val->IsObject();
bool b = val->IsArgumentsObject();
Local<Object> obj = val->ToObject(m_Context).ToLocalChecked();
if (obj.IsEmpty())
return;
String::Utf8Value objascii(m_Isolate, obj);
Handle<Array> properties = obj->GetOwnPropertyNames(m_Context).ToLocalChecked();
int len = properties->Length();
if (len == 0)
return;
for (int i = 0; i < len; ++i)
{
const Handle<Value> key = properties->Get(i);
checkProperty(key);
}
}
else if (val->IsBoolean()) {
;
}
else if (val->IsUndefined()) {
;
}
else if (val->IsSymbol()) {
;
}
else if (val->IsNull()) {
;
}
else {
;
}
}
int main(int argc, char* argv[])
{
InitializeV8(exe_path);
Isolate::CreateParams create_params;
create_params.array_buffer_allocator = v8::ArrayBuffer::Allocator::NewDefaultAllocator();
m_Isolate = v8::Isolate::New(create_params); // need to define
Isolate::Scope isolate_scope(m_Isolate);
HandleScope handle_scope(m_Isolate);
TryCatch try_catch(m_Isolate);
m_Context = v8::Context::New(m_Isolate);
Context::Scope context_scope(m_Context);
const char * src = ("const K = {a: 1, b: 2}; ");
Local<v8::String> source = v8::String::NewFromUtf8(m_Isolate, src);
Local<Script> compiled_script;
if (!Script::Compile(m_Context, source).ToLocal(&compiled_script))
{
String::Utf8Value error(m_Isolate, try_catch.Exception());
Log(*error); // The script failed to compile;
return false;
}
Local<v8::Value> result = compiled_script->Run(m_Context).ToLocalChecked(); // Run the script to get the result.
v8::Local<v8::Object> global_obj = m_Context->Global();
Local<Value> val_k = global_obj->Get(m_Context, v8::String::NewFromUtf8(m_Isolate, "K")).ToLocalChecked();
PrintValueAsString(val_k);
checkProperty(val_k);
UnInitializeV8();
delete create_params.array_buffer_allocator;
return 0;
}
