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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 <private/qstdweb_p.h>
#include <emscripten.h>
#include <emscripten/bind.h>
#include <emscripten/html5.h>
#include <emscripten/val.h>
QT_BEGIN_NAMESPACE
namespace QWasmLocalFileAccess {
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 = 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);
}
typedef std::function<void (const qstdweb::FileList &fileList)> OpenFileDialogCallback;
void openFileDialog(const std::string &accept, FileSelectMode fileSelectMode,
const OpenFileDialogCallback &filesSelected)
{
// 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));
input.set("multiple", emscripten::val(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) { filesSelected(qstdweb::FileList(input["files"])); };
changeEvent.reset(new 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 openFiles(const std::string &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)
{
openFileDialog(accept, fileSelectMode, [=](const qstdweb::FileList &files) {
fileDialogClosed(files.length());
readFiles(files, acceptFile, fileDataReady);
});
}
void openFile(const std::string &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 saveFile(const char *content, size_t size, 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(content, size);
emscripten::val document = emscripten::val::global("document");
emscripten::val window = emscripten::val::global("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);
}
} // namespace QWasmLocalFileAccess
QT_END_NAMESPACE
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