wasm: improve qstdweb::EventCallback

We are storing a copy of the this pointer in the constructor,
and later deference it to access EventCallback object
memebers. This makes the class noncopyable: delete
the copy constructor to make sure it isn’t.

Also change the callback API to propagate the event
to the event callback.

Change-Id: Ida4bb192b3e905b260ebeec30293aad71b7d8c49
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>
This commit is contained in:
Morten Johan Sørvig 2021-11-25 12:55:10 +01:00
parent 7c54988b1b
commit 5958c28d9f
3 changed files with 30 additions and 15 deletions

View File

@ -151,7 +151,7 @@ void File::stream(uint32_t offset, uint32_t length, char *buffer, const std::fun
return;
}
char *nextChunkBuffer = chunkBuffer + result.byteLength();
fileReader->onLoad([=]() { (*chunkCompleted)(nextChunkBegin, nextChunkBuffer); });
fileReader->onLoad([=](emscripten::val) { (*chunkCompleted)(nextChunkBegin, nextChunkBuffer); });
qstdweb::Blob blob = fileHandle.slice(nextChunkBegin, nextChunkEnd);
fileReader->readAsArrayBuffer(blob);
};
@ -203,17 +203,17 @@ void FileReader::readAsArrayBuffer(const Blob &blob) const
m_fileReader.call<void>("readAsArrayBuffer", blob.m_blob);
}
void FileReader::onLoad(const std::function<void ()> &onLoad)
void FileReader::onLoad(const std::function<void(emscripten::val)> &onLoad)
{
m_onLoad.reset(new EventCallback(m_fileReader, "load", onLoad));
}
void FileReader::onError(const std::function<void ()> &onError)
void FileReader::onError(const std::function<void(emscripten::val)> &onError)
{
m_onError.reset(new EventCallback(m_fileReader, "error", onError));
}
void FileReader::onAbort(const std::function<void ()> &onAbort)
void FileReader::onAbort(const std::function<void(emscripten::val)> &onAbort)
{
m_onAbort.reset(new EventCallback(m_fileReader, "abort", onAbort));
}
@ -305,11 +305,19 @@ emscripten::val Uint8Array::constructor_()
// Registers a callback function for a named event on the given element. The event
// name must be the name as returned by the Event.type property: e.g. "load", "error".
EventCallback::EventCallback(emscripten::val element, const std::string &name, const std::function<void ()> &fn)
:m_fn(fn)
EventCallback::~EventCallback()
{
element.set(contextPropertyName(name).c_str(), emscripten::val(intptr_t(this)));
element.set((std::string("on") + name).c_str(), emscripten::val::module_property("qtStdWebEventCallbackActivate"));
m_element.set(contextPropertyName(m_eventName).c_str(), emscripten::val::undefined());
m_element.set((std::string("on") + m_eventName).c_str(), emscripten::val::undefined());
}
EventCallback::EventCallback(emscripten::val element, const std::string &name, const std::function<void(emscripten::val)> &fn)
:m_element(element)
,m_eventName(name)
,m_fn(fn)
{
m_element.set(contextPropertyName(m_eventName).c_str(), emscripten::val(intptr_t(this)));
m_element.set((std::string("on") + m_eventName).c_str(), emscripten::val::module_property("qtStdWebEventCallbackActivate"));
}
void EventCallback::activate(emscripten::val event)
@ -317,7 +325,7 @@ void EventCallback::activate(emscripten::val event)
emscripten::val target = event["target"];
std::string eventName = event["type"].as<std::string>();
EventCallback *that = reinterpret_cast<EventCallback *>(target[contextPropertyName(eventName).c_str()].as<intptr_t>());
that->m_fn();
that->m_fn(event);
}
std::string EventCallback::contextPropertyName(const std::string &eventName)

View File

@ -129,9 +129,9 @@ namespace qstdweb {
ArrayBuffer result() const;
void readAsArrayBuffer(const Blob &blob) const;
void onLoad(const std::function<void ()> &onLoad);
void onError(const std::function<void ()> &onError);
void onAbort(const std::function<void ()> &onAbort);
void onLoad(const std::function<void(emscripten::val)> &onLoad);
void onError(const std::function<void(emscripten::val)> &onError);
void onAbort(const std::function<void(emscripten::val)> &onAbort);
private:
emscripten::val m_fileReader = emscripten::val::global("FileReader").new_();
@ -166,11 +166,18 @@ namespace qstdweb {
class EventCallback
{
public:
EventCallback(emscripten::val element, const std::string &name, const std::function<void ()> &fn);
EventCallback() = default;
~EventCallback();
EventCallback(EventCallback const&) = delete;
EventCallback& operator=(EventCallback const&) = delete;
EventCallback(emscripten::val element, const std::string &name,
const std::function<void(emscripten::val)> &fn);
static void activate(emscripten::val event);
private:
static std::string contextPropertyName(const std::string &eventName);
std::function<void ()> m_fn;
emscripten::val m_element = emscripten::val::undefined();
std::string m_eventName;
std::function<void(emscripten::val)> m_fn;
};
}

View File

@ -96,7 +96,7 @@ void openFileDialog(const std::string &accept, FileSelectMode fileSelectMode,
// Note: there is no event in case the user cancels the file dialog.
static std::unique_ptr<qstdweb::EventCallback> changeEvent;
auto callback = [=]() { filesSelected(qstdweb::FileList(input["files"])); };
auto callback = [=](emscripten::val) { filesSelected(qstdweb::FileList(input["files"])); };
changeEvent.reset(new qstdweb::EventCallback(input, "change", callback));
// Activate file input