treewide: separate Lua runtime resources

Move classes required for Lua runtime support into a new `luci-lua-runtime`
package. Also replace the `luci.http` and `luci.util` classes in
`luci-lib-base` with stubbed versions interacting with the ucode based
runtime environment.

Finally merge `luci-base-ucode` into the remainders of `luci-base`.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 162 insertions, 0 deletions

diff --git a/modules/luci-base/ucode/runtime.uc b/modules/luci-base/ucode/runtime.uc
new file mode 100644
index 0000000000..a8b6812e74
--- /dev/null
+++ b/modules/luci-base/ucode/runtime.uc
@@ -0,0 +1,162 @@
+// Copyright 2022 Jo-Philipp Wich <jo@mein.io>
+// Licensed to the public under the Apache License 2.0.
+
+import { access, basename } from 'fs';
+import { cursor } from 'uci';
+
+const template_directory = '/usr/share/ucode/luci/template';
+
+function cut_message(msg) {
+	return trim(replace(msg, /\n--\n.*$/, ''));
+}
+
+function format_nested_exception(ex) {
+	let msg = replace(cut_message(ex.message), /(\n+(  \|[^\n]*(\n|$))+)/, (m, m1) => {
+		m1 = replace(m1, /(^|\n)  \| ?/g, '$1');
+		m = match(m1, /^(.+?)\n(In.*line \d+, byte \d+:.+)$/);
+
+		return `
+			<div class="exception">
+				<div class="message">${cut_message(m ? m[1] : m1)}</div>
+				${m ? `<pre class="context">${trim(m[2])}</pre>` : ''}
+			</div>
+		`;
+	});
+
+	return `
+		<div class="exception">
+			<div class="message">${cut_message(msg)}</div>
+			<pre class="context">${trim(ex.stacktrace[0].context)}</pre>
+		</div>
+	`;
+}
+
+function format_lua_exception(ex) {
+	let m = match(ex.message, /^(.+)\nstack traceback:\n(.+)$/);
+
+	return `
+		<div class="exception">
+			<div class="message">${cut_message(m ? m[1] : ex.message)}</div>
+			<pre class="context">${m ? trim(replace(m[2], /(^|\n)\t/g, '$1')) : ex.stacktrace[0].context}</pre>
+		</div>
+	`;
+}
+
+const Class = {
+	init_lua: function() {
+		if (!this.L) {
+			this.L = this.env.dispatcher.load_luabridge().create();
+			this.L.set('L', proto({ write: print }, this.env));
+			this.L.invoke('require', 'luci.ucodebridge');
+
+			this.env.lua_active = true;
+		}
+
+		return this.L;
+	},
+
+	render_ucode: function(path, scope) {
+		let tmplfunc = loadfile(path, { raw_mode: false });
+		call(tmplfunc, null, scope ?? {});
+	},
+
+	render_lua: function(path, scope) {
+		let vm = this.init_lua();
+		let render = vm.get('_G', 'luci', 'ucodebridge', 'render');
+
+		render.call(path, scope ?? {});
+	},
+
+	trycompile: function(path) {
+		let ucode_path = `${template_directory}/${path}.ut`;
+
+		if (access(ucode_path)) {
+			try {
+				loadfile(ucode_path, { raw_mode: false });
+			}
+			catch (ucode_err) {
+				return `Unable to compile '${path}' as ucode template: ${format_nested_exception(ucode_err)}`;
+			}
+		}
+		else {
+			try {
+				let vm = this.init_lua();
+				let compile = vm.get('_G', 'luci', 'ucodebridge', 'compile');
+
+				compile.call(path);
+			}
+			catch (lua_err) {
+				return `Unable to compile '${path}' as Lua template: ${format_lua_exception(lua_err)}`;
+			}
+		}
+
+		return true;
+	},
+
+	render_any: function(path, scope) {
+		let ucode_path = `${template_directory}/${path}.ut`;
+
+		scope = proto(scope ?? {}, this.scopes[-1]);
+
+		push(this.scopes, scope);
+
+		try {
+			if (access(ucode_path))
+				this.render_ucode(ucode_path, scope);
+			else
+				this.render_lua(path, scope);
+		}
+		catch (ex) {
+			pop(this.scopes);
+			die(ex);
+		}
+
+		pop(this.scopes);
+	},
+
+	render: function(path, scope) {
+		let self = this;
+		this.env.http.write(render(() => self.render_any(path, scope)));
+	},
+
+	call: function(modname, method, ...args) {
+		let vm = this.init_lua();
+		let lcall = vm.get('_G', 'luci', 'ucodebridge', 'call');
+
+		return lcall.call(modname, method, ...args);
+	}
+};
+
+export default function(env) {
+	const self = proto({ env: env ??= {}, scopes: [ proto(env, global) ], global }, Class);
+	const uci = cursor();
+
+	// determine theme
+	let media = uci.get('luci', 'main', 'mediaurlbase');
+	let status = self.trycompile(`themes/${basename(media)}/header`);
+
+	if (status !== true) {
+		media = null;
+
+		for (let k, v in uci.get_all('luci', 'themes')) {
+			if (substr(k, 0, 1) != '.') {
+				status = self.trycompile(`themes/${basename(v)}/header`);
+
+				if (status === true) {
+					media = v;
+					break;
+				}
+			}
+		}
+
+		if (!media)
+			error500(`Unable to render any theme header template, last error was:\n${status}`);
+	}
+
+	self.env.media = media;
+	self.env.theme = basename(media);
+	self.env.resource = uci.get('luci', 'main', 'resourcebase');
+	self.env.include = (...args) => self.render_any(...args);
+
+	return self;
+};