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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#include "qwasmlocalfileaccess_p.h"
#include "qlocalfileapi_p.h"
#include <private/qstdweb_p.h>
#include <emscripten.h>
#include <emscripten/bind.h>
#include <emscripten/html5.h>
#include <emscripten/val.h>
QT_BEGIN_NAMESPACE
namespace QWasmLocalFileAccess {
namespace FileDialog {
namespace {
bool hasLocalFilesApi()
{
return !qstdweb::window()["showOpenFilePicker"].isUndefined();
}
void showOpenViaHTMLPolyfill(const QStringList &accept, FileSelectMode fileSelectMode,
qstdweb::PromiseCallbacks onFilesSelected)
{
// Create file input html element which will display a native file dialog
// and call back to our onchange handler once the user has selected
// one or more files.
emscripten::val document = emscripten::val::global("document");
emscripten::val input = document.call<emscripten::val>("createElement", std::string("input"));
input.set("type", "file");
input.set("style", "display:none");
// input.set("accept", emscripten::val(accept));
Q_UNUSED(accept);
input.set("multiple", emscripten::val(fileSelectMode == FileSelectMode::MultipleFiles));
// Note: there is no event in case the user cancels the file dialog.
static std::unique_ptr<qstdweb::EventCallback> changeEvent;
auto callback = [=](emscripten::val) { onFilesSelected.thenFunc(input["files"]); };
changeEvent = std::make_unique<qstdweb::EventCallback>(input, "change", callback);
// Activate file input
emscripten::val body = document["body"];
body.call<void>("appendChild", input);
input.call<void>("click");
body.call<void>("removeChild", input);
}
void showOpenViaLocalFileApi(const QStringList &accept, FileSelectMode fileSelectMode,
qstdweb::PromiseCallbacks callbacks)
{
using namespace qstdweb;
auto options = LocalFileApi::makeOpenFileOptions(accept, fileSelectMode == FileSelectMode::MultipleFiles);
Promise::make(
window(), QStringLiteral("showOpenFilePicker"),
{
.thenFunc = [=](emscripten::val fileHandles) mutable {
std::vector<emscripten::val> filePromises;
filePromises.reserve(fileHandles["length"].as<int>());
for (int i = 0; i < fileHandles["length"].as<int>(); ++i)
filePromises.push_back(fileHandles[i].call<emscripten::val>("getFile"));
Promise::all(std::move(filePromises), callbacks);
},
.catchFunc = callbacks.catchFunc,
.finallyFunc = callbacks.finallyFunc,
}, std::move(options));
}
void showSaveViaLocalFileApi(const std::string &fileNameHint, qstdweb::PromiseCallbacks callbacks)
{
using namespace qstdweb;
using namespace emscripten;
auto options = LocalFileApi::makeSaveFileOptions(QStringList(), fileNameHint);
Promise::make(
window(), QStringLiteral("showSaveFilePicker"),
std::move(callbacks), std::move(options));
}
} // namespace
void showOpen(const QStringList &accept, FileSelectMode fileSelectMode,
qstdweb::PromiseCallbacks callbacks)
{
hasLocalFilesApi() ?
showOpenViaLocalFileApi(accept, fileSelectMode, std::move(callbacks)) :
showOpenViaHTMLPolyfill(accept, fileSelectMode, std::move(callbacks));
}
bool canShowSave()
{
return hasLocalFilesApi();
}
void showSave(const std::string &fileNameHint, qstdweb::PromiseCallbacks callbacks)
{
Q_ASSERT(canShowSave());
showSaveViaLocalFileApi(fileNameHint, std::move(callbacks));
}
} // namespace FileDialog
namespace {
void readFiles(const qstdweb::FileList &fileList,
const std::function<char *(uint64_t size, const std::string name)> &acceptFile,
const std::function<void ()> &fileDataReady)
{
auto readFile = std::make_shared<std::function<void(int)>>();
*readFile = [=](int fileIndex) mutable {
// Stop when all files have been processed
if (fileIndex >= fileList.length()) {
readFile.reset();
return;
}
const qstdweb::File file = qstdweb::File(fileList[fileIndex]);
// Ask caller if the file should be accepted
char *buffer = acceptFile(file.size(), file.name());
if (buffer == nullptr) {
(*readFile)(fileIndex + 1);
return;
}
// Read file data into caller-provided buffer
file.stream(buffer, [=]() {
fileDataReady();
(*readFile)(fileIndex + 1);
});
};
(*readFile)(0);
}
}
void downloadDataAsFile(const QByteArray &data, const std::string &fileNameHint)
{
// Save a file by creating programmatically clicking a download
// link to an object url to a Blob containing a copy of the file
// content. The copy is made so that the passed in content buffer
// can be released as soon as this function returns.
qstdweb::Blob contentBlob = qstdweb::Blob::copyFrom(data.constData(), data.size());
emscripten::val document = emscripten::val::global("document");
emscripten::val window = qstdweb::window();
emscripten::val contentUrl = window["URL"].call<emscripten::val>("createObjectURL", contentBlob.val());
emscripten::val contentLink = document.call<emscripten::val>("createElement", std::string("a"));
contentLink.set("href", contentUrl);
contentLink.set("download", fileNameHint);
contentLink.set("style", "display:none");
emscripten::val body = document["body"];
body.call<void>("appendChild", contentLink);
contentLink.call<void>("click");
body.call<void>("removeChild", contentLink);
window["URL"].call<emscripten::val>("revokeObjectURL", contentUrl);
}
void openFiles(const QStringList &accept, FileSelectMode fileSelectMode,
const std::function<void (int fileCount)> &fileDialogClosed,
const std::function<char *(uint64_t size, const std::string& name)> &acceptFile,
const std::function<void()> &fileDataReady)
{
FileDialog::showOpen(accept, fileSelectMode, {
.thenFunc = [=](emscripten::val result) {
auto files = qstdweb::FileList(result);
fileDialogClosed(files.length());
readFiles(files, acceptFile, fileDataReady);
},
.catchFunc = [=](emscripten::val) {
fileDialogClosed(0);
}
});
}
void openFile(const QStringList &accept,
const std::function<void (bool fileSelected)> &fileDialogClosed,
const std::function<char *(uint64_t size, const std::string& name)> &acceptFile,
const std::function<void()> &fileDataReady)
{
auto fileDialogClosedWithInt = [=](int fileCount) { fileDialogClosed(fileCount != 0); };
openFiles(accept, FileSelectMode::SingleFile, fileDialogClosedWithInt, acceptFile, fileDataReady);
}
void saveDataToFileInChunks(emscripten::val fileHandle, const QByteArray &data)
{
using namespace emscripten;
using namespace qstdweb;
Promise::make(fileHandle, QStringLiteral("createWritable"), {
.thenFunc = [=](val writable) {
struct State {
size_t written;
std::function<void(val result)> continuation;
};
auto state = std::make_shared<State>();
state->written = 0u;
state->continuation = [=](val) mutable {
const size_t remaining = data.size() - state->written;
if (remaining == 0) {
Promise::make(writable, QStringLiteral("close"), { .thenFunc = [=](val) {} });
state.reset();
return;
}
static constexpr size_t desiredChunkSize = 1024u;
const auto currentChunkSize = std::min(remaining, desiredChunkSize);
Promise::make(writable, QStringLiteral("write"), {
.thenFunc = state->continuation,
}, val(typed_memory_view(currentChunkSize, data.constData() + state->written)));
state->written += currentChunkSize;
};
state->continuation(val::undefined());
},
});
}
void saveFile(const QByteArray &data, const std::string &fileNameHint)
{
if (!FileDialog::canShowSave()) {
downloadDataAsFile(data, fileNameHint);
return;
}
FileDialog::showSave(fileNameHint, {
.thenFunc = [=](emscripten::val result) {
saveDataToFileInChunks(result, data);
},
});
}
} // namespace QWasmLocalFileAccess
QT_END_NAMESPACE
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