Thanks for the explanation, but it's still blur to me. I'm trying to wrap
those two maps into an interceptor class. Please see the attached. It
works for lines such as:
if (option.verbose)
but it fails on lines:
output[request.host] = 1;
The script runs, but the final output is:
google.com:
google.net:
google.org:
yahoo.com:
Instead, the correct result should be:
google.com: 1
google.net: 1
google.org: 1
yahoo.com: 3
On Friday, June 30, 2017 at 11:21:11 AM UTC-4, Jakob Kummerow wrote:
>
> There are no conversions happening. In the script, "output" is a regular
> JavaScript object, with all the behavior you would expect.
>
> On the C++ side, "output" is a map<string, string>, but "output_obj" is a
> JavaScript object created from that map (via the WrapMap(output) call),
> and that's what's exposed to the script.
>
>
> On Fri, Jun 30, 2017 at 3:31 PM, wxz <xzwan...@gmail.com <javascript:>>
> wrote:
>
>> a follow up question, in the script, the 'output' map is used as
>> map<string, int>:
>>
>> output[request.host] = 1;
>> output[request.host]++
>>
>> however, it's a map<string, string> in c++ side, which part of the c++
>> code handles such conversion?
>>
>>
>> On Thursday, June 29, 2017 at 5:07:20 PM UTC-4, Jakob Kummerow wrote:
>>
>>> The equivalent of options.verbose is options["verbose"] (note the
>>> quotes). Does that help?
>>>
>>> On Thu, Jun 29, 2017 at 10:07 PM, wxz <xzwan...@gmail.com> wrote:
>>>
>>>> hi all,
>>>>
>>>> there are two maps used in this example, one for 'options', one for
>>>> 'output'. My question is, why is that in the script, the brackets [] works
>>>> for 'output', but not for 'options'?
>>>>
>>>> For example, if change the line:
>>>> options.verbose ===> options[verbose]
>>>> it returns error: verbose is not defined
>>>>
>>>> However, 'output[request.host]' is perfectly fine.
>>>>
>>>> The two maps are installed with the same code, the wrap/unwrap are the
>>>> same, what's the difference?
>>>>
>>>> I guess my confusion is what exactly does bracket mean here? Does it
>>>> invoke the named property interceptor?
>>>>
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>>>
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#include "map_interceptor.h"
Local<v8::Value> MapInterceptor::GetNamedProperty(v8::Isolate* isolate,
const std::string& property)
{
if (internal_map.count(property)) {
return gin::ConvertToV8(isolate, internal_map[property]);
}
else {
return Local<v8::Value>();
}
}
bool MapInterceptor::SetNamedProperty(v8::Isolate* isolate,
const std::string& property, v8::Local<v8::Value> value)
{
internal_map[property] = gin::V8ToString(value);
return true;
}
std::vector<std::string> MapInterceptor::EnumerateNamedProperties(
v8::Isolate* isolate)
{
std::vector<std::string> result;
for (auto it = internal_map.begin(); it != internal_map.end(); ++it) {
result.push_back(it->first);
}
return result;
}
#pragma once
#include "gin/arguments.h"
#include "gin/handle.h"
#include "gin/interceptor.h"
#include "gin/object_template_builder.h"
#include "gin/wrappable.h"
#include "gin/public/wrapper_info.h"
#include "v8.h"
#include <map>
#include <vector>
#include <string>
#include <utility>
using gin::Wrappable;
using gin::NamedPropertyInterceptor;
using gin::WrapperInfo;
using v8::Isolate;
using v8::Local;
class MapInterceptor : public Wrappable<MapInterceptor>,
public NamedPropertyInterceptor
{
public:
static WrapperInfo kWrapperInfo;
static gin::Handle<MapInterceptor> Create(v8::Isolate* isolate) {
return gin::CreateHandle(isolate, new MapInterceptor(isolate));
}
// gin::NamedPropertyInterceptor
Local<v8::Value> GetNamedProperty(v8::Isolate* isolate,
const std::string& property);
bool SetNamedProperty(v8::Isolate* isolate,
const std::string& property,
v8::Local<v8::Value> value);
std::vector<std::string> EnumerateNamedProperties(
v8::Isolate* isolate) override;
void PrintMap() {
for (auto it = internal_map.begin(); it != internal_map.end(); ++it)
{
std::pair<std::string, std::string> entry = *it;
printf("%s: %s\n", entry.first.c_str(), entry.second.c_str());
}
}
private:
explicit MapInterceptor(Isolate* isolate)
: NamedPropertyInterceptor(isolate, this) { }
~MapInterceptor() override { }
// gin::Wrappable
gin:: ObjectTemplateBuilder GetObjectTemplateBuilder(
v8::Isolate* isolate) override {
return gin::Wrappable<MapInterceptor>::GetObjectTemplateBuilder(isolate)
.AddNamedPropertyInterceptor();
}
std::map<std::string, std::string> internal_map;
DISALLOW_COPY_AND_ASSIGN(MapInterceptor);
};
