name : HookCodeFactory.js /* MIT License http://www.opensource.org/licenses/mit-license.php Author Tobias Koppers @sokra */ "use strict"; class HookCodeFactory { constructor(config) { this.config = config; this.options = undefined; this._args = undefined; } create(options) { this.init(options); let fn; switch (this.options.type) { case "sync": fn = new Function( this.args(), '"use strict";\n' + this.header() + this.contentWithInterceptors({ onError: err => `throw ${err};\n`, onResult: result => `return ${result};\n`, resultReturns: true, onDone: () => "", rethrowIfPossible: true }) ); break; case "async": fn = new Function( this.args({ after: "_callback" }), '"use strict";\n' + this.header() + this.contentWithInterceptors({ onError: err => `_callback(${err});\n`, onResult: result => `_callback(null, ${result});\n`, onDone: () => "_callback();\n" }) ); break; case "promise": let errorHelperUsed = false; const content = this.contentWithInterceptors({ onError: err => { errorHelperUsed = true; return `_error(${err});\n`; }, onResult: result => `_resolve(${result});\n`, onDone: () => "_resolve();\n" }); let code = ""; code += '"use strict";\n'; code += this.header(); code += "return new Promise((function(_resolve, _reject) {\n"; if (errorHelperUsed) { code += "var _sync = true;\n"; code += "function _error(_err) {\n"; code += "if(_sync)\n"; code += "_resolve(Promise.resolve().then((function() { throw _err; })));\n"; code += "else\n"; code += "_reject(_err);\n"; code += "};\n"; } code += content; if (errorHelperUsed) { code += "_sync = false;\n"; } code += "}));\n"; fn = new Function(this.args(), code); break; } this.deinit(); return fn; } setup(instance, options) { instance._x = options.taps.map(t => t.fn); } /** * @param {{ type: "sync" | "promise" | "async", taps: Array<Tap>, interceptors: Array<Interceptor> }} options */ init(options) { this.options = options; this._args = options.args.slice(); } deinit() { this.options = undefined; this._args = undefined; } contentWithInterceptors(options) { if (this.options.interceptors.length > 0) { const onError = options.onError; const onResult = options.onResult; const onDone = options.onDone; let code = ""; for (let i = 0; i < this.options.interceptors.length; i++) { const interceptor = this.options.interceptors[i]; if (interceptor.call) { code += `${this.getInterceptor(i)}.call(${this.args({ before: interceptor.context ? "_context" : undefined })});\n`; } } code += this.content( Object.assign(options, { onError: onError && (err => { let code = ""; for (let i = 0; i < this.options.interceptors.length; i++) { const interceptor = this.options.interceptors[i]; if (interceptor.error) { code += `${this.getInterceptor(i)}.error(${err});\n`; } } code += onError(err); return code; }), onResult: onResult && (result => { let code = ""; for (let i = 0; i < this.options.interceptors.length; i++) { const interceptor = this.options.interceptors[i]; if (interceptor.result) { code += `${this.getInterceptor(i)}.result(${result});\n`; } } code += onResult(result); return code; }), onDone: onDone && (() => { let code = ""; for (let i = 0; i < this.options.interceptors.length; i++) { const interceptor = this.options.interceptors[i]; if (interceptor.done) { code += `${this.getInterceptor(i)}.done();\n`; } } code += onDone(); return code; }) }) ); return code; } else { return this.content(options); } } header() { let code = ""; if (this.needContext()) { code += "var _context = {};\n"; } else { code += "var _context;\n"; } code += "var _x = this._x;\n"; if (this.options.interceptors.length > 0) { code += "var _taps = this.taps;\n"; code += "var _interceptors = this.interceptors;\n"; } return code; } needContext() { for (const tap of this.options.taps) if (tap.context) return true; return false; } callTap(tapIndex, { onError, onResult, onDone, rethrowIfPossible }) { let code = ""; let hasTapCached = false; for (let i = 0; i < this.options.interceptors.length; i++) { const interceptor = this.options.interceptors[i]; if (interceptor.tap) { if (!hasTapCached) { code += `var _tap${tapIndex} = ${this.getTap(tapIndex)};\n`; hasTapCached = true; } code += `${this.getInterceptor(i)}.tap(${ interceptor.context ? "_context, " : "" }_tap${tapIndex});\n`; } } code += `var _fn${tapIndex} = ${this.getTapFn(tapIndex)};\n`; const tap = this.options.taps[tapIndex]; switch (tap.type) { case "sync": if (!rethrowIfPossible) { code += `var _hasError${tapIndex} = false;\n`; code += "try {\n"; } if (onResult) { code += `var _result${tapIndex} = _fn${tapIndex}(${this.args({ before: tap.context ? "_context" : undefined })});\n`; } else { code += `_fn${tapIndex}(${this.args({ before: tap.context ? "_context" : undefined })});\n`; } if (!rethrowIfPossible) { code += "} catch(_err) {\n"; code += `_hasError${tapIndex} = true;\n`; code += onError("_err"); code += "}\n"; code += `if(!_hasError${tapIndex}) {\n`; } if (onResult) { code += onResult(`_result${tapIndex}`); } if (onDone) { code += onDone(); } if (!rethrowIfPossible) { code += "}\n"; } break; case "async": let cbCode = ""; if (onResult) cbCode += `(function(_err${tapIndex}, _result${tapIndex}) {\n`; else cbCode += `(function(_err${tapIndex}) {\n`; cbCode += `if(_err${tapIndex}) {\n`; cbCode += onError(`_err${tapIndex}`); cbCode += "} else {\n"; if (onResult) { cbCode += onResult(`_result${tapIndex}`); } if (onDone) { cbCode += onDone(); } cbCode += "}\n"; cbCode += "})"; code += `_fn${tapIndex}(${this.args({ before: tap.context ? "_context" : undefined, after: cbCode })});\n`; break; case "promise": code += `var _hasResult${tapIndex} = false;\n`; code += `var _promise${tapIndex} = _fn${tapIndex}(${this.args({ before: tap.context ? "_context" : undefined })});\n`; code += `if (!_promise${tapIndex} || !_promise${tapIndex}.then)\n`; code += ` throw new Error('Tap function (tapPromise) did not return promise (returned ' + _promise${tapIndex} + ')');\n`; code += `_promise${tapIndex}.then((function(_result${tapIndex}) {\n`; code += `_hasResult${tapIndex} = true;\n`; if (onResult) { code += onResult(`_result${tapIndex}`); } if (onDone) { code += onDone(); } code += `}), function(_err${tapIndex}) {\n`; code += `if(_hasResult${tapIndex}) throw _err${tapIndex};\n`; code += onError(`_err${tapIndex}`); code += "});\n"; break; } return code; } callTapsSeries({ onError, onResult, resultReturns, onDone, doneReturns, rethrowIfPossible }) { if (this.options.taps.length === 0) return onDone(); const firstAsync = this.options.taps.findIndex(t => t.type !== "sync"); const somethingReturns = resultReturns || doneReturns; let code = ""; let current = onDone; let unrollCounter = 0; for (let j = this.options.taps.length - 1; j >= 0; j--) { const i = j; const unroll = current !== onDone && (this.options.taps[i].type !== "sync" || unrollCounter++ > 20); if (unroll) { unrollCounter = 0; code += `function _next${i}() {\n`; code += current(); code += `}\n`; current = () => `${somethingReturns ? "return " : ""}_next${i}();\n`; } const done = current; const doneBreak = skipDone => { if (skipDone) return ""; return onDone(); }; const content = this.callTap(i, { onError: error => onError(i, error, done, doneBreak), onResult: onResult && (result => { return onResult(i, result, done, doneBreak); }), onDone: !onResult && done, rethrowIfPossible: rethrowIfPossible && (firstAsync < 0 || i < firstAsync) }); current = () => content; } code += current(); return code; } callTapsLooping({ onError, onDone, rethrowIfPossible }) { if (this.options.taps.length === 0) return onDone(); const syncOnly = this.options.taps.every(t => t.type === "sync"); let code = ""; if (!syncOnly) { code += "var _looper = (function() {\n"; code += "var _loopAsync = false;\n"; } code += "var _loop;\n"; code += "do {\n"; code += "_loop = false;\n"; for (let i = 0; i < this.options.interceptors.length; i++) { const interceptor = this.options.interceptors[i]; if (interceptor.loop) { code += `${this.getInterceptor(i)}.loop(${this.args({ before: interceptor.context ? "_context" : undefined })});\n`; } } code += this.callTapsSeries({ onError, onResult: (i, result, next, doneBreak) => { let code = ""; code += `if(${result} !== undefined) {\n`; code += "_loop = true;\n"; if (!syncOnly) code += "if(_loopAsync) _looper();\n"; code += doneBreak(true); code += `} else {\n`; code += next(); code += `}\n`; return code; }, onDone: onDone && (() => { let code = ""; code += "if(!_loop) {\n"; code += onDone(); code += "}\n"; return code; }), rethrowIfPossible: rethrowIfPossible && syncOnly }); code += "} while(_loop);\n"; if (!syncOnly) { code += "_loopAsync = true;\n"; code += "});\n"; code += "_looper();\n"; } return code; } callTapsParallel({ onError, onResult, onDone, rethrowIfPossible, onTap = (i, run) => run() }) { if (this.options.taps.length <= 1) { return this.callTapsSeries({ onError, onResult, onDone, rethrowIfPossible }); } let code = ""; code += "do {\n"; code += `var _counter = ${this.options.taps.length};\n`; if (onDone) { code += "var _done = (function() {\n"; code += onDone(); code += "});\n"; } for (let i = 0; i < this.options.taps.length; i++) { const done = () => { if (onDone) return "if(--_counter === 0) _done();\n"; else return "--_counter;"; }; const doneBreak = skipDone => { if (skipDone || !onDone) return "_counter = 0;\n"; else return "_counter = 0;\n_done();\n"; }; code += "if(_counter <= 0) break;\n"; code += onTap( i, () => this.callTap(i, { onError: error => { let code = ""; code += "if(_counter > 0) {\n"; code += onError(i, error, done, doneBreak); code += "}\n"; return code; }, onResult: onResult && (result => { let code = ""; code += "if(_counter > 0) {\n"; code += onResult(i, result, done, doneBreak); code += "}\n"; return code; }), onDone: !onResult && (() => { return done(); }), rethrowIfPossible }), done, doneBreak ); } code += "} while(false);\n"; return code; } args({ before, after } = {}) { let allArgs = this._args; if (before) allArgs = [before].concat(allArgs); if (after) allArgs = allArgs.concat(after); if (allArgs.length === 0) { return ""; } else { return allArgs.join(", "); } } getTapFn(idx) { return `_x[${idx}]`; } getTap(idx) { return `_taps[${idx}]`; } getInterceptor(idx) { return `_interceptors[${idx}]`; } } module.exports = HookCodeFactory;