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109 lines
2.8 KiB
109 lines
2.8 KiB
var Traverse = require('traverse');
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var EventEmitter = require('events').EventEmitter;
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module.exports = Chainsaw;
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function Chainsaw (builder) {
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var saw = Chainsaw.saw(builder, {});
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var r = builder.call(saw.handlers, saw);
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if (r !== undefined) saw.handlers = r;
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return saw.chain();
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};
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Chainsaw.saw = function (builder, handlers) {
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var saw = new EventEmitter;
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saw.handlers = handlers;
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saw.actions = [];
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saw.step = 0;
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saw.chain = function () {
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var ch = Traverse(saw.handlers).map(function (node) {
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if (this.isRoot) return node;
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var ps = this.path;
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if (typeof node === 'function') {
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this.update(function () {
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saw.actions.push({
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path : ps,
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args : [].slice.call(arguments)
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});
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return ch;
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});
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}
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});
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process.nextTick(function () {
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saw.emit('begin');
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saw.next();
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});
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return ch;
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};
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saw.next = function () {
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var action = saw.actions[saw.step];
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saw.step ++;
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if (!action) {
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saw.emit('end');
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}
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else if (!action.trap) {
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var node = saw.handlers;
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action.path.forEach(function (key) { node = node[key] });
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node.apply(saw.handlers, action.args);
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}
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};
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saw.nest = function (cb) {
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var args = [].slice.call(arguments, 1);
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var autonext = true;
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if (typeof cb === 'boolean') {
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var autonext = cb;
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cb = args.shift();
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}
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var s = Chainsaw.saw(builder, {});
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var r = builder.call(s.handlers, s);
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if (r !== undefined) s.handlers = r;
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cb.apply(s.chain(), args);
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if (autonext !== false) s.on('end', saw.next);
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};
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saw.trap = function (name, cb) {
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var ps = Array.isArray(name) ? name : [name];
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saw.actions.push({
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path : ps,
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step : saw.step,
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cb : cb,
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trap : true
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});
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};
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saw.down = function (name) {
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var ps = (Array.isArray(name) ? name : [name]).join('/');
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var i = saw.actions.slice(saw.step).map(function (x) {
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if (x.trap && x.step <= saw.step) return false;
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return x.path.join('/') == ps;
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}).indexOf(true);
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if (i >= 0) saw.step += i;
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else saw.step = saw.actions.length;
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var act = saw.actions[saw.step - 1];
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if (act && act.trap) {
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// It's a trap!
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saw.step = act.step;
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act.cb();
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}
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else saw.next();
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};
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saw.jump = function (step) {
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saw.step = step;
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saw.next();
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};
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return saw;
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};
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