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#include "storage.h"
#include "emscripten.h"
#include <filesystem>
#include <fstream>
EM_JS(int, inbrowser, (), { return typeof window !== 'undefined'; });
EM_JS(int, inworker, (), { return typeof WorkerGlobalScope !== 'undefined' &&
self instanceof WorkerGlobalScope; });
std::string getprefix() {
return inbrowser() || inworker() ? "/tables/" : "./tables/";
}
EM_ASYNC_JS(int, loadfs, (), {
const inBrowser = typeof window !== 'undefined';
const inWorker = typeof WorkerGlobalScope !== 'undefined' &&
self instanceof WorkerGlobalScope;
console.assert(inBrowser || inWorker, "Non-browsers not supported");
const dir = '/tables';
if (!FS.analyzePath(dir).exists)
FS.mkdir(dir);
if (FS.analyzePath(dir).object.mount.mountpoint != dir) {
FS.mount(IDBFS, { autoPersist: true }, dir);
await new Promise((resolve, reject) => {
FS.syncfs(true, function (err) {
if (err)
reject(err);
else
resolve(true);
});
});
}
});
EM_ASYNC_JS(int, download_and_store, (const char *key, const char *url), {
const inBrowser = typeof window !== 'undefined';
const inWorker = typeof WorkerGlobalScope !== 'undefined' &&
self instanceof WorkerGlobalScope;
console.assert(inBrowser || inWorker, "Non-browsers not supported");
// This is a workaround related to usign WASM64
// JavaScript's UTF8ToString expects a pointer argument, which for JS is
// of type "number", but WASM64 is passing a BigInt. See also:
// https://github.com/emscripten-core/emscripten/issues/21541
// (but I could not make the suggested solution work in this case).
// TODO: check if there is a better workaround.
const non64_url = Number(url);
const non64_key = Number(key);
url = UTF8ToString(non64_url);
key = UTF8ToString(non64_key);
let response = await fetch(url);
if (!response.ok) {
console.log("Error downloading data for " + key);
console.log("" + response.status + ": " + response.statusText);
return 0;
}
let data = await response.bytes();
var stream = FS.open("/tables/" + key, "w+");
FS.write(stream, data, 0, data.length, 0);
FS.close(stream);
console.log("Data for " + key + " stored (" + data.length + " bytes)");
return 1;
});
bool storage::read(std::string key, size_t data_size, char *data)
{
loadfs();
std::filesystem::path path(getprefix() + key);
if (!std::filesystem::exists(path))
return false;
std::ifstream ifs(path, std::ios::binary);
ifs.read(data, data_size);
ifs.close();
return !ifs.fail();
}
bool storage::write(std::string key, size_t data_size, const char *data)
{
loadfs();
std::filesystem::path path(getprefix() + key);
std::ofstream ofs(path, std::ios::binary);
ofs.write(data, data_size);
ofs.close();
return !ofs.fail();
}
int storage::download(std::string key, std::string url)
{
loadfs();
return download_and_store(key.c_str(), url.c_str());
}
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