diff --git a/src/com/google/javascript/jscomp/RescopeGlobalSymbols.java b/src/com/google/javascript/jscomp/RescopeGlobalSymbols.java index d7886e146de..a3a5bf8ef4e 100644 --- a/src/com/google/javascript/jscomp/RescopeGlobalSymbols.java +++ b/src/com/google/javascript/jscomp/RescopeGlobalSymbols.java @@ -130,6 +130,14 @@ private boolean isCrossModuleName(String name) { || compiler.getCodingConvention().isExported(name, false); } + private static boolean isExternVar(String varname, NodeTraversal t) { + if (varname.isEmpty()) { + return false; + } + Var v = t.getScope().getVar(varname); + return v == null || v.isExtern(); + } + private void addExternForGlobalSymbolNamespace() { Node varNode = IR.var(IR.name(globalSymbolNamespace)); CompilerInput input = compiler.getSynthesizedExternsInput(); @@ -143,36 +151,32 @@ public void process(Node externs, Node root) { if (addExtern) { addExternForGlobalSymbolNamespace(); } - // Rewrite all references to global symbols to properties of a - // single symbol by: - // (If necessary the 4 traversals could be combined. They are left - // separate for readability reasons.) - // 1. turning global named function statements into var assignments. + + // Rewrite all references to global symbols to properties of a single symbol: + + // Turn global named function statements into var assignments. NodeTraversal.traverseEs6( compiler, root, new RewriteGlobalFunctionStatementsToVarAssignmentsCallback()); - // 2. find global names that are used in more than one module. Those that - // are have to be rewritten. + + // Find global names that are used in more than one module. Those that + // are have to be rewritten. List nonMutatingPasses = new ArrayList<>(); nonMutatingPasses.add(new FindCrossModuleNamesCallback()); - // and find names that may refering functions that reference this. + + // And find names that may refer to functions that reference this. nonMutatingPasses.add(new FindNamesReferencingThis()); CombinedCompilerPass.traverse(compiler, root, nonMutatingPasses); - // 3. rewriting all references to be property accesses of the single symbol. + + // Rewrite all references to be property accesses of the single symbol. RewriteScopeCallback rewriteScope = new RewriteScopeCallback(); NodeTraversal.traverseEs6(compiler, root, rewriteScope); - // 4. removing the var from statements in global scope if the declared names - // have been rewritten in the previous pass. + + // Remove the var from statements in global scope if the declared names have been rewritten + // in the previous pass. NodeTraversal.traverseEs6(compiler, root, new RemoveGlobalVarCallback()); rewriteScope.declareModuleGlobals(); - - // Extra pass which makes all extern global symbols reference window - // explicitly. - NodeTraversal.traverseEs6( - compiler, - root, - new MakeExternsReferenceWindowExplicitly()); } /** @@ -287,8 +291,8 @@ public void visit(NodeTraversal t, Node n, Node parent) { /** * Visits each NAME token and checks whether it refers to a global variable. - * If yes, rewrites the name to be a property access on the - * "globalSymbolNamespace". + * If yes, rewrites the name to be a property access on the "globalSymbolNamespace". + * If the NAME is an extern variable, it becomes a property access on window. * * 
var a = 1, b = 2, c = 3;
* becomes @@ -302,11 +306,9 @@ public void visit(NodeTraversal t, Node n, Node parent) { * 
a()
* becomes * 
(0,NS.a)()
- * Notice the special syntax here to preserve the *this* semantics in the - * function call. + * Notice the special syntax here to preserve the *this* semantics in the function call. */ private class RewriteScopeCallback extends AbstractPostOrderCallback { - List preDeclarations = new ArrayList<>(); @Override @@ -319,22 +321,18 @@ public void visit(NodeTraversal t, Node n, Node parent) { if (parent.isFunction() && name.isEmpty()) { return; } - Var var = t.getScope().getVar(name); - if (var == null) { - return; - } - // Don't touch externs. - if (var.isExtern()) { + if (isExternVar(name, t)) { + visitExtern(n, parent); return; } // When the globalSymbolNamespace is used as a local variable name // add suffix to avoid shadowing the namespace. Also add a suffix // if a name starts with the name of the globalSymbolNamespace and // the suffix. - if (!var.isExtern() && !var.isGlobal() + Var var = t.getScope().getVar(name); + if (!var.isGlobal() && (name.equals(globalSymbolNamespace) - || name.startsWith( - globalSymbolNamespace + DISAMBIGUATION_SUFFIX))) { + || name.startsWith(globalSymbolNamespace + DISAMBIGUATION_SUFFIX))) { n.setString(name + DISAMBIGUATION_SUFFIX); compiler.reportCodeChange(); } @@ -344,8 +342,7 @@ public void visit(NodeTraversal t, Node n, Node parent) { } Node nameNode = var.getNameNode(); // The exception variable (e in try{}catch(e){}) should not be rewritten. - if (nameNode != null && nameNode.getParent() != null - && nameNode.getParent().isCatch()) { + if (nameNode != null && nameNode.getParent() != null && nameNode.getParent().isCatch()) { return; } replaceSymbol(n, name, t.getInput()); @@ -360,18 +357,15 @@ private void replaceSymbol(Node node, String name, CompilerInput input) { if (!parent.isVar()) { return; } - // If it is a var declaration, but no cross module names are declared - // we also don't have to do anything. - boolean hasCrossModuleChildren = false; + boolean hasInterestingChildren = false; for (Node c : parent.children()) { - // Var child is no longer a name means it was transformed already - // which means there was a cross module name. + // VAR child is no longer a name means it was transformed already. if (!c.isName() || isCrossModuleName(c.getString())) { - hasCrossModuleChildren = true; + hasInterestingChildren = true; break; } } - if (!hasCrossModuleChildren) { + if (!hasInterestingChildren) { return; } } @@ -411,6 +405,27 @@ private void replaceSymbol(Node node, String name, CompilerInput input) { compiler.reportCodeChange(); } + /** + * Rewrites extern names to be explicit children of window instead of only implicitly + * referencing it. This enables injecting window into a scope and make all global symbols + * depend on the injected object. + */ + private void visitExtern(Node nameNode, Node parent) { + String name = nameNode.getString(); + if (globalSymbolNamespace.equals(name) || SPECIAL_EXTERNS.contains(name)) { + return; + } + Node windowPropAccess = IR.getprop(IR.name(WINDOW), IR.string(name)); + if (parent.isVar() && nameNode.hasOneChild()) { + Node assign = IR.assign(windowPropAccess, nameNode.getFirstChild().detachFromParent()); + assign.setJSDocInfo(parent.getJSDocInfo()); + parent.replaceChild(nameNode, assign.srcrefTree(parent)); + } else { + parent.replaceChild(nameNode, windowPropAccess.srcrefTree(nameNode)); + } + compiler.reportCodeChange(); + } + /** * Adds back declarations for variables that do not cross module boundaries. * Must be called after RemoveGlobalVarCallback. @@ -421,8 +436,7 @@ void declareModuleGlobals() { && global.root.getFirstChild().isVar()) { global.root.getFirstChild().addChildToBack(global.name); } else { - global.root.addChildToFront( - IR.var(global.name).srcref(global.name)); + global.root.addChildToFront(IR.var(global.name).srcref(global.name)); } compiler.reportCodeChange(); } @@ -515,32 +529,4 @@ private Node joinOnComma(List commas, Node source) { return comma; } } - - /** - * Rewrites extern names to be explicit children of window instead of only - * implicitly referencing it. - * This enables injecting window into a scope and make all global symbol - * depend on the injected object. - */ - private class MakeExternsReferenceWindowExplicitly extends - AbstractPostOrderCallback { - - @Override - public void visit(NodeTraversal t, Node n, Node parent) { - if (!n.isName()) { - return; - } - String name = n.getString(); - if (globalSymbolNamespace.equals(name) - || SPECIAL_EXTERNS.contains(name)) { - return; - } - Var var = t.getScope().getVar(name); - if (name.length() > 0 && (var == null || var.isExtern())) { - parent.replaceChild(n, IR.getprop(IR.name(WINDOW), IR.string(name)) - .srcrefTree(n)); - compiler.reportCodeChange(); - } - } - } }