Adding a number of work-in-progress packages. Some data structures built on top of the key-value store and an http client, among others.

git-svn-id: https://www.unprompted.com/svn/projects/tildefriends/trunk@3310 ed5197a5-7fde-0310-b194-c3ffbd925b24

packages/cory/libdocument/libdocument.js

@@ -0,0 +1,106 @@
+"use strict";
+
+// A document store.
+
+//! {"category": "libraries"}
+
+class DocumentStore {
+	constructor(prefix) {
+		this._prefix = prefix;
+	}
+
+	async _get(name) {
+		let node;
+		try {
+			node = JSON.parse(await database.get(this._prefix + ":node:" + JSON.stringify(name)));
+		} catch (error) {
+			node = {version: null};
+		}
+		return node;
+	}
+
+	async _addKey(name) {
+		let list = JSON.parse(await database.get(this._prefix + ":keys") || "[]");
+		if (list.indexOf(name) == -1) {
+			list.push(name);
+			list.sort();
+		}
+		await database.set(this._prefix + ":keys", JSON.stringify(list));
+	}
+
+	async _removeKey(name) {
+		let list = JSON.parse(await database.get(this._prefix + ":keys") || "[]");
+		let index = list.indexOf(name);
+		if (index != -1) {
+			list.splice(index, 1);
+		}
+		await database.set(this._prefix + ":keys", JSON.stringify(list));
+	}
+
+	async set(name, value) {
+		let node = await this._get(name);
+		let version = (node.version || 0) + 1;
+		await database.set(this._prefix + ":version:" + JSON.stringify(name) + ":" + version.toString(), JSON.stringify(value));
+		node.deleted = value == undefined;
+		node.version = version;
+		await database.set(this._prefix + ":node:" + JSON.stringify(name), JSON.stringify(node));
+		if (node.deleted) {
+			await this._removeKey(name);
+		} else {
+			await this._addKey(name);
+		}
+	}
+
+	async get(name, version) {
+		let queryVersion = version || (await this._get(name)).version || 0;
+		let value = await database.get(this._prefix + ":version:" + JSON.stringify(name) + ":" + queryVersion.toString());
+		return value ? JSON.parse(value) : undefined;
+	}
+
+	async getAll() {
+		return JSON.parse(await database.get(this._prefix + ":keys") || "[]");
+	}
+
+	async setVersion(name, version, value) {
+		await database.set(this._prefix + ":version:" + JSON.stringify(name) + ":" + version.toString(), JSON.stringify(value));
+	}
+}
+
+async function dump() {
+	terminal.print("Dumping everything.");
+	let keys = await database.getAll();
+	for (let key in keys) {
+		terminal.print(keys[key], " = ", await database.get(keys[key]));
+		database.remove(keys[key]);
+	}
+}
+
+async function test() {
+	terminal.print("Running a test.");
+	let ds = new DocumentStore("cory");
+	await ds.set("cory", 1);
+	await ds.set("cory", 2);
+	await ds.set("cory", 3);
+	terminal.print((await ds.get("cory")).toString());
+	await ds.set("alice", "hello, world!");
+	terminal.print(await ds.get("alice"));
+	terminal.print(JSON.stringify(await ds.getAll()));
+	await ds.set("cory", null);
+	terminal.print(JSON.stringify(await ds.getAll()));
+	terminal.print((await ds.get("cory", 2)).toString());
+	terminal.print("Done.");
+}
+
+if (imports.terminal) {
+	//dump().then(test).then(dump).catch(terminal.print);
+}
+
+exports.DocumentStore = function(name) {
+	let ds = new DocumentStore(name);
+	return {
+		get: ds.get.bind(ds),
+		set: ds.set.bind(ds),
+		getAll: ds.getAll.bind(ds),
+		setVersion: ds.setVersion.bind(ds),
+	};
+}