Files
ic10emu/www/src/js/session.js
2024-03-23 17:04:10 -07:00

125 lines
3.0 KiB
JavaScript

async function setDocFragment(content) {
const obj = JSON.stringify({ sessions: [{ content }] })
const bytes = new TextEncoder().encode(obj);
try {
const c_bytes = await compress(bytes);
const fragment = base64url_encode(c_bytes);
window.history.replaceState(null, "", `#${fragment}`);
} catch (e) {
console.log("Error compressing content fragment:", e);
return;
}
}
async function decompressFragment(c_bytes) {
try {
const bytes = await decompress(c_bytes);
const content = new TextDecoder().decode(bytes);
return content;
} catch (e) {
console.log("Error decompressing content fragment:", e);
return null;
}
}
function isJsonContent(content) {
try {
const obj = JSON.parse(content);
return [true, obj];
} catch (_) {
return [false, null];
}
}
async function getContentFromFragment() {
const fragment = window.location.hash.slice(1);
if (fragment.length > 0) {
const c_bytes = base64url_decode(fragment);
const data = await decompressFragment(c_bytes);
if (data !== null) {
const [is_json, session] = isJsonContent(data);
if (is_json) {
try {
const content = session.sessions[0].content
editor.getSession().setValue(content);
return;
} catch (e) {
console.log("Bad session data:", e);
}
} else {
editor.getSession().setValue(data);
return;
}
}
}
editor.getSession().setValue(default_content);
}
async function* streamAsyncIterator(stream) {
// Get a lock on the stream
const reader = stream.getReader();
try {
while (true) {
// Read from the stream
const { done, value } = await reader.read();
if (done) return;
yield value;
}
}
finally {
reader.releaseLock();
}
}
function base64url_encode(buffer) {
return btoa(Array.from(new Uint8Array(buffer), b => String.fromCharCode(b)).join(''))
.replace(/\+/g, '-')
.replace(/\//g, '_')
.replace(/=+$/, '');
}
function base64url_decode(value) {
const m = value.length % 4;
return Uint8Array.from(atob(
value.replace(/-/g, '+')
.replace(/_/g, '/')
.padEnd(value.length + (m === 0 ? 0 : 4 - m), '=')
), c => c.charCodeAt(0)).buffer
}
async function concatUintArrays(arrays) {
const blob = new Blob(arrays);
const buffer = await blob.arrayBuffer();
return new Uint8Array(buffer);
}
async function compress(bytes) {
const s = new Blob([bytes]).stream();
const cs = s.pipeThrough(
new CompressionStream('deflate-raw')
);
const chunks = [];
for await (const chunk of streamAsyncIterator(cs)) {
chunks.push(chunk);
}
return await concatUintArrays(chunks);
}
async function decompress(bytes) {
const s = new Blob([bytes]).stream();
const ds = s.pipeThrough(
new DecompressionStream('deflate-raw')
);
const chunks = [];
for await (const chunk of streamAsyncIterator(ds)) {
chunks.push(chunk);
}
return await concatUintArrays(chunks);
}