646 lines
24 KiB
JavaScript
646 lines
24 KiB
JavaScript
/***********************************************************************
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A JavaScript tokenizer / parser / beautifier / compressor.
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https://github.com/mishoo/UglifyJS2
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-------------------------------- (C) ---------------------------------
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Author: Mihai Bazon
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<mihai.bazon@gmail.com>
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http://mihai.bazon.net/blog
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Distributed under the BSD license:
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Copyright 2012 (c) Mihai Bazon <mihai.bazon@gmail.com>
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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* Redistributions of source code must retain the above
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copyright notice, this list of conditions and the following
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disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the following
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disclaimer in the documentation and/or other materials
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provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER “AS IS” AND ANY
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EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
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OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
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TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
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THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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SUCH DAMAGE.
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***********************************************************************/
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// The layout of the compressor follows the code generator (see
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// output.js). Basically each node will have a "squeeze" method
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// that will apply all known compression rules for that node, and
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// return a new node (or the original node if there was no
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// compression). We can't quite use the TreeWalker for this
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// because it's too simplistic.
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// The Compressor object is for storing the options and for
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// maintaining various internal state that might be useful for
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// squeezing nodes.
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function Compressor(options, false_by_default) {
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options = defaults(options, {
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sequences : !false_by_default,
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properties : !false_by_default,
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dead_code : !false_by_default,
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keep_comps : !false_by_default,
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drop_debugger : !false_by_default,
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unsafe : !false_by_default,
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ifs : !false_by_default,
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comparations : !false_by_default,
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evaluate : !false_by_default,
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warnings : true
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});
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var stack = [];
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return {
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option : function(key) { return options[key] },
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push_node : function(node) { stack.push(node) },
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pop_node : function() { return stack.pop() },
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stack : function() { return stack },
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parent : function(n) {
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return stack[stack.length - 2 - (n || 0)];
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},
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warn : function() {
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if (options.warnings)
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AST_Node.warn.apply(AST_Node, arguments);
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}
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};
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};
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(function(){
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AST_Node.DEFMETHOD("squeeze", function(){
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return this;
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});
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function make_node(ctor, orig, props) {
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if (!props) props = {};
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if (!props.start) props.start = orig.start;
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if (!props.end) props.end = orig.end;
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return new ctor(props);
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};
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function SQUEEZE(nodetype, squeeze) {
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nodetype.DEFMETHOD("squeeze", function(compressor){
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compressor.push_node(this);
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var new_node = squeeze(this, compressor);
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compressor.pop_node();
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return new_node || this;
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});
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};
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function do_list(array, compressor) {
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return MAP(array, function(node){
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return node.squeeze(compressor);
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});
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};
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function tighten_body(statements, compressor) {
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statements = do_list(statements, compressor);
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statements = eliminate_spurious_blocks(statements);
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if (compressor.option("dead_code")) {
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statements = eliminate_dead_code(statements, compressor);
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}
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if (compressor.option("sequences")) {
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statements = sequencesize(statements);
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}
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return statements;
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};
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function eliminate_spurious_blocks(statements) {
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return statements.reduce(function(a, stat){
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if (stat.TYPE == "BlockStatement") {
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// XXX: no instanceof here because we would catch
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// AST_Lambda-s and other blocks too. perhaps we
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// should refine the hierarchy.
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a.push.apply(a, stat.body);
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} else {
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a.push(stat);
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}
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return a;
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}, []);
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}
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function eliminate_dead_code(statements, compressor) {
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var has_quit = false;
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return statements.reduce(function(a, stat){
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if (has_quit) {
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if (stat instanceof AST_Defun) {
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a.push(stat);
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}
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else if (compressor.option("warnings")) {
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stat.walk(new TreeWalker(function(node){
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if (node instanceof AST_Definitions || node instanceof AST_Defun) {
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compressor.warn("Declarations in unreachable code! [{line},{col}]", node.start);
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if (node instanceof AST_Definitions) {
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node = node.clone();
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node.remove_initializers();
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a.push(node);
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}
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else if (node instanceof AST_Defun) {
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a.push(node);
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}
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return true; // no point to descend
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}
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if (node instanceof AST_Scope) {
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// also don't descend any other nested scopes
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return true;
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}
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}));
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};
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} else {
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a.push(stat);
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if (stat instanceof AST_Jump) {
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has_quit = true;
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}
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}
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return a;
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}, []);
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}
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// XXX: this is destructive -- it modifies tree nodes.
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function sequencesize(statements) {
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var prev = null, last = statements.length - 1;
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if (last) statements = statements.reduce(function(a, cur, i){
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if (prev instanceof AST_SimpleStatement
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&& cur instanceof AST_SimpleStatement) {
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var seq = make_node(AST_Seq, prev, {
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first: prev.body,
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second: cur.body
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});
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prev.body = seq;
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}
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else if (i == last
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&& cur instanceof AST_Exit && cur.value
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&& a.length == 1 && prev instanceof AST_SimpleStatement) {
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// it only makes sense to do this transformation
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// if the AST gets to a single statement.
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var seq = make_node(AST_Seq, prev, {
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first: prev.body,
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second: cur.value
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});
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cur.value = seq;
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return [ cur ];
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}
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else {
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a.push(cur);
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prev = cur;
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}
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return a;
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}, []);
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return statements;
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}
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/* -----[ boolean/negation helpers ]----- */
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// methods to determine whether an expression has a boolean result type
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(function (def){
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var unary_bool = [ "!", "delete" ];
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var binary_bool = [ "in", "instanceof", "==", "!=", "===", "!==", "<", "<=", ">=", ">" ];
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def(AST_Node, function(){ return false });
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def(AST_UnaryPrefix, function(){
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return member(this.operator, unary_bool);
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});
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def(AST_Binary, function(){
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return member(this.operator, binary_bool) ||
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( (this.operator == "&&" || this.operator == "||") &&
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this.left.is_boolean() && this.right.is_boolean() );
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});
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def(AST_Conditional, function(){
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return this.consequent.is_boolean() && this.alternative.is_boolean();
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});
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def(AST_Assign, function(){
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return this.operator == "=" && this.right.is_boolean();
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});
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def(AST_Seq, function(){
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return this.second.is_boolean();
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});
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def(AST_True, function(){ return true });
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def(AST_False, function(){ return true });
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})(function(node, func){
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node.DEFMETHOD("is_boolean", func);
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});
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// methods to determine if an expression has a string result type
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(function (def){
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def(AST_Node, function(){ return false });
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def(AST_String, function(){ return true });
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def(AST_UnaryPrefix, function(){
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return this.operator == "typeof";
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});
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def(AST_Binary, function(){
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return this.operator == "+" &&
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(this.left.is_string() || this.right.is_string());
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});
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def(AST_Assign, function(){
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return this.operator == "=" && this.right.is_string();
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});
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})(function(node, func){
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node.DEFMETHOD("is_string", func);
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});
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// function best_of(ast1, ast2) {
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// return ast1.print_to_string().length > ast2.print_to_string().length ? ast2 : ast1;
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// };
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// methods to evaluate a constant expression
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(function (def){
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AST_Node.DEFMETHOD("evaluate", function(compressor, constant, not_constant){
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if (!compressor.option("evaluate")) return this;
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try {
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var val = this._eval(), ast;
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switch (typeof val) {
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case "string":
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ast = make_node(AST_String, this, {
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value: val
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});
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break;
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case "number":
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ast = make_node(AST_Number, this, {
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value: val
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});
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break;
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case "boolean":
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ast = make_node(val ? AST_True : AST_False, this);
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break;
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case "undefined":
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ast = make_node(AST_Undefined, this);
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break;
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default:
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if (val === null) {
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ast = make_node(AST_Null, this);
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break;
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}
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throw new Error(string_template("Can't handle constant of type: {type}", {
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type: typeof val
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}));
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}
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if (constant) return constant(ast, val);
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return ast;
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} catch(ex) {
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if (ex !== def) throw ex;
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if (not_constant) return not_constant(this);
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return this;
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}
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});
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function evaluate(node) {
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return node._eval();
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};
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def(AST_Node, function(){
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throw def; // not constant
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});
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def(AST_Constant, function(){
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return this.getValue();
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});
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def(AST_UnaryPrefix, function(){
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var e = this.expression;
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switch (this.operator) {
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case "!": return !evaluate(e);
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case "typeof": return typeof evaluate(e);
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case "~": return ~evaluate(e);
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case "-": return -evaluate(e);
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case "+": return +evaluate(e);
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}
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throw def;
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});
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def(AST_Binary, function(){
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var left = this.left, right = this.right;
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switch (this.operator) {
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case "&&" : return evaluate(left) && evaluate(right);
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case "||" : return evaluate(left) || evaluate(right);
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case "|" : return evaluate(left) | evaluate(right);
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case "&" : return evaluate(left) & evaluate(right);
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case "^" : return evaluate(left) ^ evaluate(right);
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case "+" : return evaluate(left) + evaluate(right);
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case "*" : return evaluate(left) * evaluate(right);
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case "/" : return evaluate(left) / evaluate(right);
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case "%" : return evaluate(left) % evaluate(right);
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case "-" : return evaluate(left) - evaluate(right);
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case "<<" : return evaluate(left) << evaluate(right);
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case ">>" : return evaluate(left) >> evaluate(right);
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case ">>>" : return evaluate(left) >>> evaluate(right);
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case "==" : return evaluate(left) == evaluate(right);
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case "===" : return evaluate(left) === evaluate(right);
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case "!=" : return evaluate(left) != evaluate(right);
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case "!==" : return evaluate(left) !== evaluate(right);
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case "<" : return evaluate(left) < evaluate(right);
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case "<=" : return evaluate(left) <= evaluate(right);
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case ">" : return evaluate(left) > evaluate(right);
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case ">=" : return evaluate(left) >= evaluate(right);
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case "in" : return evaluate(left) in evaluate(right);
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case "instanceof" : return evaluate(left) instanceof evaluate(right);
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}
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throw def;
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});
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def(AST_Conditional, function(){
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return evaluate(this.condition)
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? evaluate(this.consequent)
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: evaluate(this.alternative);
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});
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})(function(node, func){
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node.DEFMETHOD("_eval", func);
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});
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// method to negate an expression
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(function(def){
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function basic_negation(exp) {
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return make_node(AST_UnaryPrefix, exp, {
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operator: "!",
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expression: exp
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});
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};
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def(AST_Node, function(){
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return basic_negation(this);
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});
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def(AST_Statement, function(){
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throw new Error("Cannot evaluate a statement");
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});
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def(AST_UnaryPrefix, function(){
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if (this.operator == "!" && this.expression.is_boolean())
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return this.expression();
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return basic_negation(this);
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});
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def(AST_Seq, function(compressor){
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var self = this.clone();
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self.second = self.second.negate(compressor);
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return self;
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});
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def(AST_Conditional, function(){
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var self = this.clone();
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self.consequent = self.consequent.negate(compressor);
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self.alternative = self.alternative.negate(compressor);
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//return best_of(basic_negation(this), self);
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return self;
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});
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def(AST_Binary, function(compressor){
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var self = this.clone(), op = this.operator;
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if (compressor.option("comparations")) switch (op) {
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case "<=" : self.operator = ">" ; return self;
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case "<" : self.operator = ">=" ; return self;
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case ">=" : self.operator = "<" ; return self;
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case ">" : self.operator = "<=" ; return self;
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}
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switch (op) {
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case "==" : self.operator = "!="; return self;
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case "!=" : self.operator = "=="; return self;
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case "===": self.operator = "!=="; return self;
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case "!==": self.operator = "==="; return self;
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case "&&":
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self.operator = "||";
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self.left = self.left.negate(compressor);
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self.right = self.right.negate(compressor);
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//return best_of(basic_negation(this), self);
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return self;
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case "||":
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self.operator = "&&";
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self.left = self.left.negate(compressor);
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self.right = self.right.negate(compressor);
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//return best_of(basic_negation(this), self);
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return self;
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}
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return basic_negation(this);
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});
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})(function(node, func){
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node.DEFMETHOD("negate", func);
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});
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/* -----[ node squeezers ]----- */
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SQUEEZE(AST_Debugger, function(self, compressor){
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if (compressor.option("drop_debugger"))
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return new AST_EmptyStatement(self);
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});
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SQUEEZE(AST_LabeledStatement, function(self, compressor){
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self = self.clone();
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self.body = self.body.squeeze(compressor);
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return self.label.references.length == 0 ? self.body : self;
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});
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SQUEEZE(AST_Statement, function(self, compressor){
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self = self.clone();
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self.body = self.body.squeeze(compressor);
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return self;
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});
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SQUEEZE(AST_BlockStatement, function(self, compressor){
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self = self.clone();
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self.body = tighten_body(self.body, compressor);
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if (self.body.length == 1 && !self.required)
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return self.body[0];
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return self;
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});
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SQUEEZE(AST_EmptyStatement, function(self, compressor){
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return self;
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});
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SQUEEZE(AST_DWLoop, function(self, compressor){
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self = self.clone();
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self.condition = self.condition.squeeze(compressor);
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self.body = self.body.squeeze(compressor);
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return self;
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});
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SQUEEZE(AST_For, function(self, compressor){
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self = self.clone();
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if (self.init) self.init = self.init.squeeze(compressor);
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if (self.condition) self.condition = self.condition.squeeze(compressor);
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if (self.step) self.step = self.step.squeeze(compressor);
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self.body = self.body.squeeze(compressor);
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return self;
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});
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SQUEEZE(AST_ForIn, function(self, compressor){
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self = self.clone();
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self.init = self.init.squeeze(compressor);
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self.object = self.object.squeeze(compressor);
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self.body = self.body.squeeze(compressor);
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return self;
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});
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SQUEEZE(AST_With, function(self, compressor){
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self = self.clone();
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self.expression = self.expression.squeeze(compressor);
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self.body = self.body.squeeze(compressor);
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});
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SQUEEZE(AST_Exit, function(self, compressor){
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self = self.clone();
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if (self.value) self.value = self.value.squeeze(compressor);
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return self;
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});
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SQUEEZE(AST_LoopControl, function(self, compressor){
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self = self.clone();
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if (self.label) self.label = self.label.squeeze(compressor);
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return self;
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});
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SQUEEZE(AST_If, function(self, compressor){
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self = self.clone();
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self.condition = self.condition.squeeze(compressor);
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self.body = self.body.squeeze(compressor);
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if (self.alternative)
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self.alternative = self.alternative.squeeze(compressor);
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if (!compressor.option("ifs")) return self;
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return self;
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});
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AST_If.DEFMETHOD("switch_branches", function(){
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});
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SQUEEZE(AST_Switch, function(self, compressor){
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self = self.clone();
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self.expression = self.expression.squeeze(compressor);
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self.body = self.body.squeeze(compressor);
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return self;
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});
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SQUEEZE(AST_Case, function(self, compressor){
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self = self.clone();
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self.expression = self.expression.squeeze(compressor);
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self.body = tighten_body(self.body, compressor);
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return self;
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});
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SQUEEZE(AST_Try, function(self, compressor){
|
|
self = self.clone();
|
|
self.btry = self.btry.squeeze(compressor);
|
|
if (self.bcatch) self.bcatch = self.bcatch.squeeze(compressor);
|
|
if (self.bfinally) self.bfinally = self.bfinally.squeeze(compressor);
|
|
return self;
|
|
});
|
|
|
|
AST_Definitions.DEFMETHOD("remove_initializers", function(){
|
|
this.definitions = this.definitions.map(function(def){
|
|
var def = def.clone();
|
|
def.value = null;
|
|
return def;
|
|
});
|
|
});
|
|
|
|
SQUEEZE(AST_Definitions, function(self, compressor){
|
|
self = self.clone();
|
|
self.definitions = do_list(self.definitions, compressor);
|
|
return self;
|
|
});
|
|
|
|
SQUEEZE(AST_VarDef, function(self, compressor){
|
|
self = self.clone();
|
|
if (self.value) self.value = self.value.squeeze(compressor);
|
|
return self;
|
|
});
|
|
|
|
SQUEEZE(AST_Lambda, function(self, compressor){
|
|
self = self.clone();
|
|
if (self.name) self.name = self.name.squeeze(compressor);
|
|
self.argnames = do_list(self.argnames, compressor);
|
|
self.body = self.body.squeeze(compressor);
|
|
return self;
|
|
});
|
|
|
|
SQUEEZE(AST_Call, function(self, compressor){
|
|
self = self.clone();
|
|
self.expression = self.expression.squeeze(compressor);
|
|
self.args = do_list(self.args, compressor);
|
|
return self;
|
|
});
|
|
|
|
SQUEEZE(AST_Seq, function(self, compressor){
|
|
self = self.clone();
|
|
self.first = self.first.squeeze(compressor);
|
|
self.second = self.second.squeeze(compressor);
|
|
return self;
|
|
});
|
|
|
|
SQUEEZE(AST_Dot, function(self, compressor){
|
|
self = self.clone();
|
|
self.expression = self.expression.squeeze(compressor);
|
|
return self;
|
|
});
|
|
|
|
SQUEEZE(AST_Sub, function(self, compressor){
|
|
self = self.clone();
|
|
self.expression = self.expression.squeeze(compressor);
|
|
var prop = self.property = self.property.squeeze(compressor);
|
|
if (prop instanceof AST_String && compressor.option("properties")) {
|
|
prop = prop.getValue();
|
|
if (is_identifier(prop)) {
|
|
self = new AST_Dot(self);
|
|
self.property = prop;
|
|
}
|
|
}
|
|
return self;
|
|
});
|
|
|
|
SQUEEZE(AST_Unary, function(self, compressor){
|
|
self = self.clone();
|
|
self.expression = self.expression.squeeze(compressor);
|
|
return self;
|
|
});
|
|
|
|
SQUEEZE(AST_UnaryPrefix, function(self, compressor){
|
|
self = self.clone();
|
|
self.expression = self.expression.squeeze(compressor);
|
|
return self.evaluate(compressor);
|
|
});
|
|
|
|
SQUEEZE(AST_Binary, function(self, compressor){
|
|
self = self.clone();
|
|
self.left = self.left.squeeze(compressor);
|
|
self.right = self.right.squeeze(compressor);
|
|
return self.evaluate(compressor);
|
|
});
|
|
|
|
SQUEEZE(AST_Assign, function(self, compressor){
|
|
self = self.clone();
|
|
self.left = self.left.squeeze(compressor);
|
|
self.right = self.right.squeeze(compressor);
|
|
return self;
|
|
});
|
|
|
|
SQUEEZE(AST_Conditional, function(self, compressor){
|
|
self = self.clone();
|
|
self.condition = self.condition.squeeze(compressor);
|
|
self.consequent = self.consequent.squeeze(compressor);
|
|
self.alternative = self.alternative.squeeze(compressor);
|
|
return self;
|
|
});
|
|
|
|
SQUEEZE(AST_Array, function(self, compressor){
|
|
self = self.clone();
|
|
self.elements = do_list(self.elements, compressor);
|
|
return self;
|
|
});
|
|
|
|
SQUEEZE(AST_Object, function(self, compressor){
|
|
self = self.clone();
|
|
self.properties = do_list(self.properties, compressor);
|
|
return self;
|
|
});
|
|
|
|
SQUEEZE(AST_ObjectProperty, function(self, compressor){
|
|
self = self.clone();
|
|
self.value = self.value.squeeze(compressor);
|
|
return self;
|
|
});
|
|
|
|
})();
|