526 lines
18 KiB
JavaScript
526 lines
18 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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"use strict";
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function SymbolDef(scope, index, orig) {
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this.name = orig.name;
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this.orig = [ orig ];
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this.scope = scope;
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this.references = [];
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this.global = false;
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this.mangled_name = null;
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this.undeclared = false;
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this.index = index;
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this.id = SymbolDef.next_id++;
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};
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SymbolDef.next_id = 1;
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SymbolDef.prototype = {
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unmangleable: function(options) {
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if (!options) options = {};
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return (this.global && !options.toplevel)
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|| this.undeclared
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|| (!options.eval && (this.scope.uses_eval || this.scope.uses_with))
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|| (options.keep_fnames
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&& (this.orig[0] instanceof AST_SymbolLambda
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|| this.orig[0] instanceof AST_SymbolDefun));
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},
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mangle: function(options) {
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var cache = options.cache && options.cache.props;
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if (this.global && cache && cache.has(this.name)) {
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this.mangled_name = cache.get(this.name);
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}
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else if (!this.mangled_name && !this.unmangleable(options)) {
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var s = this.scope;
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var sym = this.orig[0];
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if (options.ie8 && sym instanceof AST_SymbolLambda)
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s = s.parent_scope;
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var def;
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if (def = this.redefined()) {
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this.mangled_name = def.mangled_name || def.name;
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} else
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this.mangled_name = s.next_mangled(options, this);
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if (this.global && cache) {
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cache.set(this.name, this.mangled_name);
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}
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}
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},
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redefined: function() {
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return this.defun && this.defun.variables.get(this.name);
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}
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};
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AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
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options = defaults(options, {
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cache: null,
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ie8: false,
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});
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// pass 1: setup scope chaining and handle definitions
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var self = this;
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var scope = self.parent_scope = null;
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var labels = new Dictionary();
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var defun = null;
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var tw = new TreeWalker(function(node, descend){
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if (node instanceof AST_Catch) {
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var save_scope = scope;
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scope = new AST_Scope(node);
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scope.init_scope_vars(save_scope);
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descend();
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scope = save_scope;
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return true;
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}
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if (node instanceof AST_Scope) {
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node.init_scope_vars(scope);
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var save_scope = scope;
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var save_defun = defun;
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var save_labels = labels;
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defun = scope = node;
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labels = new Dictionary();
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descend();
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scope = save_scope;
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defun = save_defun;
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labels = save_labels;
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return true; // don't descend again in TreeWalker
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}
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if (node instanceof AST_LabeledStatement) {
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var l = node.label;
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if (labels.has(l.name)) {
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throw new Error(string_template("Label {name} defined twice", l));
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}
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labels.set(l.name, l);
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descend();
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labels.del(l.name);
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return true; // no descend again
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}
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if (node instanceof AST_With) {
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for (var s = scope; s; s = s.parent_scope)
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s.uses_with = true;
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return;
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}
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if (node instanceof AST_Symbol) {
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node.scope = scope;
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}
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if (node instanceof AST_Label) {
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node.thedef = node;
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node.references = [];
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}
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if (node instanceof AST_SymbolLambda) {
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defun.def_function(node);
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}
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else if (node instanceof AST_SymbolDefun) {
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// Careful here, the scope where this should be defined is
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// the parent scope. The reason is that we enter a new
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// scope when we encounter the AST_Defun node (which is
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// instanceof AST_Scope) but we get to the symbol a bit
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// later.
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(node.scope = defun.parent_scope).def_function(node);
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}
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else if (node instanceof AST_SymbolVar) {
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defun.def_variable(node);
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if (defun !== scope) {
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node.mark_enclosed(options);
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var def = scope.find_variable(node);
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if (node.thedef !== def) {
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node.thedef = def;
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node.reference(options);
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}
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}
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}
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else if (node instanceof AST_SymbolCatch) {
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scope.def_variable(node).defun = defun;
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}
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else if (node instanceof AST_LabelRef) {
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var sym = labels.get(node.name);
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if (!sym) throw new Error(string_template("Undefined label {name} [{line},{col}]", {
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name: node.name,
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line: node.start.line,
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col: node.start.col
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}));
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node.thedef = sym;
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}
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});
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self.walk(tw);
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// pass 2: find back references and eval
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self.globals = new Dictionary();
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var tw = new TreeWalker(function(node, descend){
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if (node instanceof AST_LoopControl && node.label) {
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node.label.thedef.references.push(node);
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return true;
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}
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if (node instanceof AST_SymbolRef) {
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var name = node.name;
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if (name == "eval" && tw.parent() instanceof AST_Call) {
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for (var s = node.scope; s && !s.uses_eval; s = s.parent_scope) {
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s.uses_eval = true;
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}
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}
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var sym = node.scope.find_variable(name);
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if (!sym) {
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sym = self.def_global(node);
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} else if (sym.scope instanceof AST_Lambda && name == "arguments") {
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sym.scope.uses_arguments = true;
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}
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node.thedef = sym;
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node.reference(options);
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return true;
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}
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// ensure mangling works if catch reuses a scope variable
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var def;
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if (node instanceof AST_SymbolCatch && (def = node.definition().redefined())) {
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var s = node.scope;
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while (s) {
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push_uniq(s.enclosed, def);
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if (s === def.scope) break;
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s = s.parent_scope;
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}
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}
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});
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self.walk(tw);
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// pass 3: fix up any scoping issue with IE8
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if (options.ie8) {
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self.walk(new TreeWalker(function(node, descend) {
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if (node instanceof AST_SymbolCatch) {
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var name = node.name;
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var refs = node.thedef.references;
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var scope = node.thedef.defun;
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var def = scope.find_variable(name) || self.globals.get(name) || scope.def_variable(node);
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refs.forEach(function(ref) {
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ref.thedef = def;
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ref.reference(options);
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});
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node.thedef = def;
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return true;
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}
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}));
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}
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if (options.cache) {
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this.cname = options.cache.cname;
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}
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});
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AST_Toplevel.DEFMETHOD("def_global", function(node){
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var globals = this.globals, name = node.name;
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if (globals.has(name)) {
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return globals.get(name);
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} else {
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var g = new SymbolDef(this, globals.size(), node);
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g.undeclared = true;
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g.global = true;
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globals.set(name, g);
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return g;
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}
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});
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AST_Scope.DEFMETHOD("init_scope_vars", function(parent_scope){
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this.variables = new Dictionary(); // map name to AST_SymbolVar (variables defined in this scope; includes functions)
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this.functions = new Dictionary(); // map name to AST_SymbolDefun (functions defined in this scope)
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this.uses_with = false; // will be set to true if this or some nested scope uses the `with` statement
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this.uses_eval = false; // will be set to true if this or nested scope uses the global `eval`
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this.parent_scope = parent_scope; // the parent scope
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this.enclosed = []; // a list of variables from this or outer scope(s) that are referenced from this or inner scopes
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this.cname = -1; // the current index for mangling functions/variables
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});
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AST_Lambda.DEFMETHOD("init_scope_vars", function(){
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AST_Scope.prototype.init_scope_vars.apply(this, arguments);
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this.uses_arguments = false;
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this.def_variable(new AST_SymbolFunarg({
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name: "arguments",
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start: this.start,
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end: this.end
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}));
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});
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AST_Symbol.DEFMETHOD("mark_enclosed", function(options) {
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var def = this.definition();
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var s = this.scope;
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while (s) {
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push_uniq(s.enclosed, def);
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if (options.keep_fnames) {
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s.functions.each(function(d) {
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push_uniq(def.scope.enclosed, d);
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});
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}
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if (s === def.scope) break;
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s = s.parent_scope;
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}
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});
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AST_Symbol.DEFMETHOD("reference", function(options) {
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this.definition().references.push(this);
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this.mark_enclosed(options);
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});
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AST_Scope.DEFMETHOD("find_variable", function(name){
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if (name instanceof AST_Symbol) name = name.name;
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return this.variables.get(name)
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|| (this.parent_scope && this.parent_scope.find_variable(name));
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});
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AST_Scope.DEFMETHOD("def_function", function(symbol){
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this.functions.set(symbol.name, this.def_variable(symbol));
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});
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AST_Scope.DEFMETHOD("def_variable", function(symbol){
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var def;
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if (!this.variables.has(symbol.name)) {
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def = new SymbolDef(this, this.variables.size(), symbol);
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this.variables.set(symbol.name, def);
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def.global = !this.parent_scope;
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} else {
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def = this.variables.get(symbol.name);
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def.orig.push(symbol);
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}
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return symbol.thedef = def;
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});
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AST_Scope.DEFMETHOD("next_mangled", function(options){
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var ext = this.enclosed;
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out: while (true) {
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var m = base54(++this.cname);
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if (!is_identifier(m)) continue; // skip over "do"
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// https://github.com/mishoo/UglifyJS2/issues/242 -- do not
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// shadow a name reserved from mangling.
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if (options.reserved.indexOf(m) >= 0) continue;
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// we must ensure that the mangled name does not shadow a name
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// from some parent scope that is referenced in this or in
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// inner scopes.
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for (var i = ext.length; --i >= 0;) {
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var sym = ext[i];
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var name = sym.mangled_name || (sym.unmangleable(options) && sym.name);
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if (m == name) continue out;
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}
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return m;
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}
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});
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AST_Function.DEFMETHOD("next_mangled", function(options, def){
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// #179, #326
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// in Safari strict mode, something like (function x(x){...}) is a syntax error;
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// a function expression's argument cannot shadow the function expression's name
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var tricky_def = def.orig[0] instanceof AST_SymbolFunarg && this.name && this.name.definition();
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// the function's mangled_name is null when keep_fnames is true
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var tricky_name = tricky_def ? tricky_def.mangled_name || tricky_def.name : null;
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while (true) {
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var name = AST_Lambda.prototype.next_mangled.call(this, options, def);
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if (!tricky_name || tricky_name != name)
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return name;
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}
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});
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AST_Symbol.DEFMETHOD("unmangleable", function(options){
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var def = this.definition();
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return !def || def.unmangleable(options);
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});
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// labels are always mangleable
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AST_Label.DEFMETHOD("unmangleable", return_false);
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AST_Symbol.DEFMETHOD("unreferenced", function(){
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return this.definition().references.length == 0
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&& !(this.scope.uses_eval || this.scope.uses_with);
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});
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AST_Symbol.DEFMETHOD("definition", function(){
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return this.thedef;
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});
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AST_Symbol.DEFMETHOD("global", function(){
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return this.definition().global;
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});
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AST_Toplevel.DEFMETHOD("_default_mangler_options", function(options){
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options = defaults(options, {
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eval : false,
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ie8 : false,
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keep_fnames : false,
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reserved : [],
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toplevel : false,
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});
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if (!Array.isArray(options.reserved)) options.reserved = [];
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return options;
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});
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AST_Toplevel.DEFMETHOD("mangle_names", function(options){
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options = this._default_mangler_options(options);
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// Never mangle arguments
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options.reserved.push('arguments');
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// We only need to mangle declaration nodes. Special logic wired
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// into the code generator will display the mangled name if it's
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// present (and for AST_SymbolRef-s it'll use the mangled name of
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// the AST_SymbolDeclaration that it points to).
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var lname = -1;
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var to_mangle = [];
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if (options.cache) {
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this.globals.each(function(symbol){
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if (options.reserved.indexOf(symbol.name) < 0) {
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to_mangle.push(symbol);
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}
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});
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}
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var tw = new TreeWalker(function(node, descend){
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if (node instanceof AST_LabeledStatement) {
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// lname is incremented when we get to the AST_Label
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var save_nesting = lname;
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descend();
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lname = save_nesting;
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return true; // don't descend again in TreeWalker
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}
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if (node instanceof AST_Scope) {
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var p = tw.parent(), a = [];
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node.variables.each(function(symbol){
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if (options.reserved.indexOf(symbol.name) < 0) {
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a.push(symbol);
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}
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});
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to_mangle.push.apply(to_mangle, a);
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return;
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}
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if (node instanceof AST_Label) {
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var name;
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do name = base54(++lname); while (!is_identifier(name));
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node.mangled_name = name;
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return true;
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}
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if (!options.ie8 && node instanceof AST_SymbolCatch) {
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to_mangle.push(node.definition());
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return;
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}
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});
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this.walk(tw);
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to_mangle.forEach(function(def){ def.mangle(options) });
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if (options.cache) {
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options.cache.cname = this.cname;
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}
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});
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AST_Toplevel.DEFMETHOD("compute_char_frequency", function(options){
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options = this._default_mangler_options(options);
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try {
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AST_Node.prototype.print = function(stream, force_parens) {
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this._print(stream, force_parens);
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if (this instanceof AST_Symbol && !this.unmangleable(options)) {
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base54.consider(this.name, -1);
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} else if (options.properties) {
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if (this instanceof AST_Dot) {
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base54.consider(this.property, -1);
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} else if (this instanceof AST_Sub) {
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skip_string(this.property);
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}
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}
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};
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base54.consider(this.print_to_string(), 1);
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} finally {
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AST_Node.prototype.print = AST_Node.prototype._print;
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}
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base54.sort();
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function skip_string(node) {
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if (node instanceof AST_String) {
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base54.consider(node.value, -1);
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} else if (node instanceof AST_Conditional) {
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skip_string(node.consequent);
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skip_string(node.alternative);
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} else if (node instanceof AST_Sequence) {
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skip_string(node.expressions[node.expressions.length - 1]);
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}
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}
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});
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var base54 = (function() {
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var leading = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_".split("");
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var digits = "0123456789".split("");
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var chars, frequency;
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function reset() {
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frequency = Object.create(null);
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leading.forEach(function(ch) {
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frequency[ch] = 0;
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});
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digits.forEach(function(ch) {
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frequency[ch] = 0;
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});
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}
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base54.consider = function(str, delta) {
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for (var i = str.length; --i >= 0;) {
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frequency[str[i]] += delta;
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}
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};
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function compare(a, b) {
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return frequency[b] - frequency[a];
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}
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base54.sort = function() {
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chars = mergeSort(leading, compare).concat(mergeSort(digits, compare));
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};
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base54.reset = reset;
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reset();
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function base54(num) {
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var ret = "", base = 54;
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num++;
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do {
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num--;
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ret += chars[num % base];
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num = Math.floor(num / base);
|
|
base = 64;
|
|
} while (num > 0);
|
|
return ret;
|
|
};
|
|
return base54;
|
|
})();
|