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#include <mbgl/storage/default/request.hpp>
#include <mbgl/storage/response.hpp>
#include <mbgl/util/util.hpp>
#include <mbgl/util/uv.hpp>
#include <uv.h>
#include <cassert>
#include <functional>
namespace mbgl {
// Note: This requires that loop is running in the current thread (or not yet running).
Request::Request(const Resource &resource_, uv_loop_t *loop, Callback callback_)
: callback(callback_), resource(resource_) {
// When there is no loop supplied (== nullptr), the callback will be fired in an arbitrary
// thread (the thread notify() is called from) rather than kicking back to the calling thread.
if (loop) {
notify_async = new uv_async_t;
notify_async->data = nullptr;
#if UV_VERSION_MAJOR == 0 && UV_VERSION_MINOR <= 10
uv_async_init(loop, notify_async, [](uv_async_t *async, int) { notifyCallback(async); });
#else
uv_async_init(loop, notify_async, notifyCallback);
#endif
}
}
void Request::notifyCallback(uv_async_t *async) {
auto request = reinterpret_cast<Request *>(async->data);
uv::close(async);
if (!request->destruct_async) {
// We haven't created a cancel request, so we can safely delete this Request object
// since it won't be accessed in the future.
assert(request->response);
request->callback(*request->response);
delete request;
} else {
// Otherwise, we're waiting for for the destruct notification to be delivered in order
// to delete the Request object. We're doing this since we can't know whether the
// DefaultFileSource is still sending a cancel event, which means this object must still
// exist.
}
}
Request::~Request() {
if (notify_async) {
// Request objects can be destructed in other threads when the user didn't supply a loop.
MBGL_VERIFY_THREAD(tid)
}
}
void Request::notify(const std::shared_ptr<const Response> &response_) {
response = response_;
if (notify_async) {
assert(!notify_async->data);
notify_async->data = this;
uv_async_send(notify_async);
} else {
assert(response);
callback(*response);
delete this;
}
}
void Request::cancel() {
MBGL_VERIFY_THREAD(tid)
assert(notify_async);
assert(!destruct_async);
destruct_async = new uv_async_t;
destruct_async->data = nullptr;
#if UV_VERSION_MAJOR == 0 && UV_VERSION_MINOR <= 10
uv_async_init(notify_async->loop, destruct_async, [](uv_async_t *async, int) { cancelCallback(async); });
#else
uv_async_init(notify_async->loop, destruct_async, cancelCallback);
#endif
}
void Request::cancelCallback(uv_async_t *async) {
// The destruct_async will be invoked *after* the notify_async callback has already run.
auto request = reinterpret_cast<Request *>(async->data);
uv::close(async);
delete request;
}
// This gets called from the FileSource thread, and will only ever be invoked after cancel() was called
// in the original requesting thread.
void Request::destruct() {
assert(destruct_async);
assert(!destruct_async->data);
destruct_async->data = this;
uv_async_send(destruct_async);
}
}
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