diff options
Diffstat (limited to 'node_modules/uglify-js/lib/scope.js')
| -rw-r--r-- | node_modules/uglify-js/lib/scope.js | 661 |
1 files changed, 661 insertions, 0 deletions
diff --git a/node_modules/uglify-js/lib/scope.js b/node_modules/uglify-js/lib/scope.js new file mode 100644 index 000000000..74760e4f4 --- /dev/null +++ b/node_modules/uglify-js/lib/scope.js @@ -0,0 +1,661 @@ +/*********************************************************************** + + A JavaScript tokenizer / parser / beautifier / compressor. + https://github.com/mishoo/UglifyJS2 + + -------------------------------- (C) --------------------------------- + + Author: Mihai Bazon + <mihai.bazon@gmail.com> + http://mihai.bazon.net/blog + + Distributed under the BSD license: + + Copyright 2012 (c) Mihai Bazon <mihai.bazon@gmail.com> + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions + are met: + + * Redistributions of source code must retain the above + copyright notice, this list of conditions and the following + disclaimer. + + * Redistributions in binary form must reproduce the above + copyright notice, this list of conditions and the following + disclaimer in the documentation and/or other materials + provided with the distribution. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER “AS IS” AND ANY + EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE + LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, + OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR + TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF + THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + SUCH DAMAGE. + + ***********************************************************************/ + +"use strict"; + +function SymbolDef(scope, index, orig) { + this.name = orig.name; + this.orig = [ orig ]; + this.scope = scope; + this.references = []; + this.global = false; + this.mangled_name = null; + this.undeclared = false; + this.index = index; + this.id = SymbolDef.next_id++; +}; + +SymbolDef.next_id = 1; + +SymbolDef.prototype = { + unmangleable: function(options) { + if (!options) options = {}; + + return (this.global && !options.toplevel) + || this.undeclared + || (!options.eval && (this.scope.uses_eval || this.scope.uses_with)) + || (options.keep_fnames + && (this.orig[0] instanceof AST_SymbolLambda + || this.orig[0] instanceof AST_SymbolDefun)); + }, + mangle: function(options) { + var cache = options.cache && options.cache.props; + if (this.global && cache && cache.has(this.name)) { + this.mangled_name = cache.get(this.name); + } + else if (!this.mangled_name && !this.unmangleable(options)) { + var s = this.scope; + var sym = this.orig[0]; + if (!options.screw_ie8 && sym instanceof AST_SymbolLambda) + s = s.parent_scope; + var def; + if (this.defun && (def = this.defun.variables.get(this.name))) { + this.mangled_name = def.mangled_name || def.name; + } else + this.mangled_name = s.next_mangled(options, this); + if (this.global && cache) { + cache.set(this.name, this.mangled_name); + } + } + } +}; + +AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){ + options = defaults(options, { + cache: null, + screw_ie8: true, + }); + + // pass 1: setup scope chaining and handle definitions + var self = this; + var scope = self.parent_scope = null; + var labels = new Dictionary(); + var defun = null; + var tw = new TreeWalker(function(node, descend){ + if (node instanceof AST_Catch) { + var save_scope = scope; + scope = new AST_Scope(node); + scope.init_scope_vars(save_scope); + descend(); + scope = save_scope; + return true; + } + if (node instanceof AST_Scope) { + node.init_scope_vars(scope); + var save_scope = scope; + var save_defun = defun; + var save_labels = labels; + defun = scope = node; + labels = new Dictionary(); + descend(); + scope = save_scope; + defun = save_defun; + labels = save_labels; + return true; // don't descend again in TreeWalker + } + if (node instanceof AST_LabeledStatement) { + var l = node.label; + if (labels.has(l.name)) { + throw new Error(string_template("Label {name} defined twice", l)); + } + labels.set(l.name, l); + descend(); + labels.del(l.name); + return true; // no descend again + } + if (node instanceof AST_With) { + for (var s = scope; s; s = s.parent_scope) + s.uses_with = true; + return; + } + if (node instanceof AST_Symbol) { + node.scope = scope; + } + if (node instanceof AST_Label) { + node.thedef = node; + node.references = []; + } + if (node instanceof AST_SymbolLambda) { + defun.def_function(node); + } + else if (node instanceof AST_SymbolDefun) { + // Careful here, the scope where this should be defined is + // the parent scope. The reason is that we enter a new + // scope when we encounter the AST_Defun node (which is + // instanceof AST_Scope) but we get to the symbol a bit + // later. + (node.scope = defun.parent_scope).def_function(node); + } + else if (node instanceof AST_SymbolVar + || node instanceof AST_SymbolConst) { + defun.def_variable(node); + if (defun !== scope) { + node.mark_enclosed(options); + var def = scope.find_variable(node); + if (node.thedef !== def) { + node.thedef = def; + node.reference(options); + } + } + } + else if (node instanceof AST_SymbolCatch) { + scope.def_variable(node).defun = defun; + } + else if (node instanceof AST_LabelRef) { + var sym = labels.get(node.name); + if (!sym) throw new Error(string_template("Undefined label {name} [{line},{col}]", { + name: node.name, + line: node.start.line, + col: node.start.col + })); + node.thedef = sym; + } + }); + self.walk(tw); + + // pass 2: find back references and eval + var func = null; + var globals = self.globals = new Dictionary(); + var tw = new TreeWalker(function(node, descend){ + if (node instanceof AST_Lambda) { + var prev_func = func; + func = node; + descend(); + func = prev_func; + return true; + } + if (node instanceof AST_LoopControl && node.label) { + node.label.thedef.references.push(node); + return true; + } + if (node instanceof AST_SymbolRef) { + var name = node.name; + if (name == "eval" && tw.parent() instanceof AST_Call) { + for (var s = node.scope; s && !s.uses_eval; s = s.parent_scope) { + s.uses_eval = true; + } + } + var sym = node.scope.find_variable(name); + if (node.scope instanceof AST_Lambda && name == "arguments") { + node.scope.uses_arguments = true; + } + if (!sym) { + sym = self.def_global(node); + } + node.thedef = sym; + node.reference(options); + return true; + } + }); + self.walk(tw); + + // pass 3: fix up any scoping issue with IE8 + if (!options.screw_ie8) { + self.walk(new TreeWalker(function(node, descend) { + if (node instanceof AST_SymbolCatch) { + var name = node.name; + var refs = node.thedef.references; + var scope = node.thedef.defun; + var def = scope.find_variable(name) || self.globals.get(name) || scope.def_variable(node); + refs.forEach(function(ref) { + ref.thedef = def; + ref.reference(options); + }); + node.thedef = def; + return true; + } + })); + } + + if (options.cache) { + this.cname = options.cache.cname; + } +}); + +AST_Toplevel.DEFMETHOD("def_global", function(node){ + var globals = this.globals, name = node.name; + if (globals.has(name)) { + return globals.get(name); + } else { + var g = new SymbolDef(this, globals.size(), node); + g.undeclared = true; + g.global = true; + globals.set(name, g); + return g; + } +}); + +AST_Scope.DEFMETHOD("init_scope_vars", function(parent_scope){ + this.variables = new Dictionary(); // map name to AST_SymbolVar (variables defined in this scope; includes functions) + this.functions = new Dictionary(); // map name to AST_SymbolDefun (functions defined in this scope) + this.uses_with = false; // will be set to true if this or some nested scope uses the `with` statement + this.uses_eval = false; // will be set to true if this or nested scope uses the global `eval` + this.parent_scope = parent_scope; // the parent scope + this.enclosed = []; // a list of variables from this or outer scope(s) that are referenced from this or inner scopes + this.cname = -1; // the current index for mangling functions/variables +}); + +AST_Lambda.DEFMETHOD("init_scope_vars", function(){ + AST_Scope.prototype.init_scope_vars.apply(this, arguments); + this.uses_arguments = false; + this.def_variable(new AST_SymbolVar({ + name: "arguments", + start: this.start, + end: this.end + })); +}); + +AST_Symbol.DEFMETHOD("mark_enclosed", function(options) { + var def = this.definition(); + var s = this.scope; + while (s) { + push_uniq(s.enclosed, def); + if (options.keep_fnames) { + s.functions.each(function(d) { + push_uniq(def.scope.enclosed, d); + }); + } + if (s === def.scope) break; + s = s.parent_scope; + } +}); + +AST_Symbol.DEFMETHOD("reference", function(options) { + this.definition().references.push(this); + this.mark_enclosed(options); +}); + +AST_Scope.DEFMETHOD("find_variable", function(name){ + if (name instanceof AST_Symbol) name = name.name; + return this.variables.get(name) + || (this.parent_scope && this.parent_scope.find_variable(name)); +}); + +AST_Scope.DEFMETHOD("def_function", function(symbol){ + this.functions.set(symbol.name, this.def_variable(symbol)); +}); + +AST_Scope.DEFMETHOD("def_variable", function(symbol){ + var def; + if (!this.variables.has(symbol.name)) { + def = new SymbolDef(this, this.variables.size(), symbol); + this.variables.set(symbol.name, def); + def.global = !this.parent_scope; + } else { + def = this.variables.get(symbol.name); + def.orig.push(symbol); + } + return symbol.thedef = def; +}); + +AST_Scope.DEFMETHOD("next_mangled", function(options){ + var ext = this.enclosed; + out: while (true) { + var m = base54(++this.cname); + if (!is_identifier(m)) continue; // skip over "do" + + // https://github.com/mishoo/UglifyJS2/issues/242 -- do not + // shadow a name excepted from mangling. + if (options.except.indexOf(m) >= 0) continue; + + // we must ensure that the mangled name does not shadow a name + // from some parent scope that is referenced in this or in + // inner scopes. + for (var i = ext.length; --i >= 0;) { + var sym = ext[i]; + var name = sym.mangled_name || (sym.unmangleable(options) && sym.name); + if (m == name) continue out; + } + return m; + } +}); + +AST_Function.DEFMETHOD("next_mangled", function(options, def){ + // #179, #326 + // in Safari strict mode, something like (function x(x){...}) is a syntax error; + // a function expression's argument cannot shadow the function expression's name + + var tricky_def = def.orig[0] instanceof AST_SymbolFunarg && this.name && this.name.definition(); + + // the function's mangled_name is null when keep_fnames is true + var tricky_name = tricky_def ? tricky_def.mangled_name || tricky_def.name : null; + + while (true) { + var name = AST_Lambda.prototype.next_mangled.call(this, options, def); + if (!tricky_name || tricky_name != name) + return name; + } +}); + +AST_Symbol.DEFMETHOD("unmangleable", function(options){ + return this.definition().unmangleable(options); +}); + +// property accessors are not mangleable +AST_SymbolAccessor.DEFMETHOD("unmangleable", function(){ + return true; +}); + +// labels are always mangleable +AST_Label.DEFMETHOD("unmangleable", function(){ + return false; +}); + +AST_Symbol.DEFMETHOD("unreferenced", function(){ + return this.definition().references.length == 0 + && !(this.scope.uses_eval || this.scope.uses_with); +}); + +AST_Symbol.DEFMETHOD("undeclared", function(){ + return this.definition().undeclared; +}); + +AST_LabelRef.DEFMETHOD("undeclared", function(){ + return false; +}); + +AST_Label.DEFMETHOD("undeclared", function(){ + return false; +}); + +AST_Symbol.DEFMETHOD("definition", function(){ + return this.thedef; +}); + +AST_Symbol.DEFMETHOD("global", function(){ + return this.definition().global; +}); + +AST_Toplevel.DEFMETHOD("_default_mangler_options", function(options){ + return defaults(options, { + eval : false, + except : [], + keep_fnames : false, + screw_ie8 : true, + sort : false, // Ignored. Flag retained for backwards compatibility. + toplevel : false, + }); +}); + +AST_Toplevel.DEFMETHOD("mangle_names", function(options){ + options = this._default_mangler_options(options); + + // Never mangle arguments + options.except.push('arguments'); + + // We only need to mangle declaration nodes. Special logic wired + // into the code generator will display the mangled name if it's + // present (and for AST_SymbolRef-s it'll use the mangled name of + // the AST_SymbolDeclaration that it points to). + var lname = -1; + var to_mangle = []; + + if (options.cache) { + this.globals.each(function(symbol){ + if (options.except.indexOf(symbol.name) < 0) { + to_mangle.push(symbol); + } + }); + } + + var tw = new TreeWalker(function(node, descend){ + if (node instanceof AST_LabeledStatement) { + // lname is incremented when we get to the AST_Label + var save_nesting = lname; + descend(); + lname = save_nesting; + return true; // don't descend again in TreeWalker + } + if (node instanceof AST_Scope) { + var p = tw.parent(), a = []; + node.variables.each(function(symbol){ + if (options.except.indexOf(symbol.name) < 0) { + a.push(symbol); + } + }); + to_mangle.push.apply(to_mangle, a); + return; + } + if (node instanceof AST_Label) { + var name; + do name = base54(++lname); while (!is_identifier(name)); + node.mangled_name = name; + return true; + } + if (options.screw_ie8 && node instanceof AST_SymbolCatch) { + to_mangle.push(node.definition()); + return; + } + }); + this.walk(tw); + to_mangle.forEach(function(def){ def.mangle(options) }); + + if (options.cache) { + options.cache.cname = this.cname; + } +}); + +AST_Toplevel.DEFMETHOD("compute_char_frequency", function(options){ + options = this._default_mangler_options(options); + var tw = new TreeWalker(function(node){ + if (node instanceof AST_Constant) + base54.consider(node.print_to_string()); + else if (node instanceof AST_Return) + base54.consider("return"); + else if (node instanceof AST_Throw) + base54.consider("throw"); + else if (node instanceof AST_Continue) + base54.consider("continue"); + else if (node instanceof AST_Break) + base54.consider("break"); + else if (node instanceof AST_Debugger) + base54.consider("debugger"); + else if (node instanceof AST_Directive) + base54.consider(node.value); + else if (node instanceof AST_While) + base54.consider("while"); + else if (node instanceof AST_Do) + base54.consider("do while"); + else if (node instanceof AST_If) { + base54.consider("if"); + if (node.alternative) base54.consider("else"); + } + else if (node instanceof AST_Var) + base54.consider("var"); + else if (node instanceof AST_Const) + base54.consider("const"); + else if (node instanceof AST_Lambda) + base54.consider("function"); + else if (node instanceof AST_For) + base54.consider("for"); + else if (node instanceof AST_ForIn) + base54.consider("for in"); + else if (node instanceof AST_Switch) + base54.consider("switch"); + else if (node instanceof AST_Case) + base54.consider("case"); + else if (node instanceof AST_Default) + base54.consider("default"); + else if (node instanceof AST_With) + base54.consider("with"); + else if (node instanceof AST_ObjectSetter) + base54.consider("set" + node.key); + else if (node instanceof AST_ObjectGetter) + base54.consider("get" + node.key); + else if (node instanceof AST_ObjectKeyVal) + base54.consider(node.key); + else if (node instanceof AST_New) + base54.consider("new"); + else if (node instanceof AST_This) + base54.consider("this"); + else if (node instanceof AST_Try) + base54.consider("try"); + else if (node instanceof AST_Catch) + base54.consider("catch"); + else if (node instanceof AST_Finally) + base54.consider("finally"); + else if (node instanceof AST_Symbol && node.unmangleable(options)) + base54.consider(node.name); + else if (node instanceof AST_Unary || node instanceof AST_Binary) + base54.consider(node.operator); + else if (node instanceof AST_Dot) + base54.consider(node.property); + }); + this.walk(tw); + base54.sort(); +}); + +var base54 = (function() { + var string = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_0123456789"; + var chars, frequency; + function reset() { + frequency = Object.create(null); + chars = string.split("").map(function(ch){ return ch.charCodeAt(0) }); + chars.forEach(function(ch){ frequency[ch] = 0 }); + } + base54.consider = function(str){ + for (var i = str.length; --i >= 0;) { + var code = str.charCodeAt(i); + if (code in frequency) ++frequency[code]; + } + }; + base54.sort = function() { + chars = mergeSort(chars, function(a, b){ + if (is_digit(a) && !is_digit(b)) return 1; + if (is_digit(b) && !is_digit(a)) return -1; + return frequency[b] - frequency[a]; + }); + }; + base54.reset = reset; + reset(); + base54.get = function(){ return chars }; + base54.freq = function(){ return frequency }; + function base54(num) { + var ret = "", base = 54; + num++; + do { + num--; + ret += String.fromCharCode(chars[num % base]); + num = Math.floor(num / base); + base = 64; + } while (num > 0); + return ret; + }; + return base54; +})(); + +AST_Toplevel.DEFMETHOD("scope_warnings", function(options){ + options = defaults(options, { + assign_to_global : true, + eval : true, + func_arguments : true, + nested_defuns : true, + undeclared : false, // this makes a lot of noise + unreferenced : true, + }); + var tw = new TreeWalker(function(node){ + if (options.undeclared + && node instanceof AST_SymbolRef + && node.undeclared()) + { + // XXX: this also warns about JS standard names, + // i.e. Object, Array, parseInt etc. Should add a list of + // exceptions. + AST_Node.warn("Undeclared symbol: {name} [{file}:{line},{col}]", { + name: node.name, + file: node.start.file, + line: node.start.line, + col: node.start.col + }); + } + if (options.assign_to_global) + { + var sym = null; + if (node instanceof AST_Assign && node.left instanceof AST_SymbolRef) + sym = node.left; + else if (node instanceof AST_ForIn && node.init instanceof AST_SymbolRef) + sym = node.init; + if (sym + && (sym.undeclared() + || (sym.global() && sym.scope !== sym.definition().scope))) { + AST_Node.warn("{msg}: {name} [{file}:{line},{col}]", { + msg: sym.undeclared() ? "Accidental global?" : "Assignment to global", + name: sym.name, + file: sym.start.file, + line: sym.start.line, + col: sym.start.col + }); + } + } + if (options.eval + && node instanceof AST_SymbolRef + && node.undeclared() + && node.name == "eval") { + AST_Node.warn("Eval is used [{file}:{line},{col}]", node.start); + } + if (options.unreferenced + && (node instanceof AST_SymbolDeclaration || node instanceof AST_Label) + && !(node instanceof AST_SymbolCatch) + && node.unreferenced()) { + AST_Node.warn("{type} {name} is declared but not referenced [{file}:{line},{col}]", { + type: node instanceof AST_Label ? "Label" : "Symbol", + name: node.name, + file: node.start.file, + line: node.start.line, + col: node.start.col + }); + } + if (options.func_arguments + && node instanceof AST_Lambda + && node.uses_arguments) { + AST_Node.warn("arguments used in function {name} [{file}:{line},{col}]", { + name: node.name ? node.name.name : "anonymous", + file: node.start.file, + line: node.start.line, + col: node.start.col + }); + } + if (options.nested_defuns + && node instanceof AST_Defun + && !(tw.parent() instanceof AST_Scope)) { + AST_Node.warn("Function {name} declared in nested statement \"{type}\" [{file}:{line},{col}]", { + name: node.name.name, + type: tw.parent().TYPE, + file: node.start.file, + line: node.start.line, + col: node.start.col + }); + } + }); + this.walk(tw); +}); |