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Rework hoisting and goog.require/provide insertion order so nodes can…
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… blindly be inserted at the top of a scope.

Closes #2350

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=151178910
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@ChadKillingsworth
ChadKillingsworth authored and Tyler Breisacher committed Mar 27, 2017
1 parent d414fc4 commit e68fcaa
Showing 1 changed file with 62 additions and 70 deletions.
132 changes: 62 additions & 70 deletions src/com/google/javascript/jscomp/ProcessCommonJSModules.java
View file
Expand Up @@ -95,7 +95,6 @@ public void process(Node externs, Node root) {
NodeTraversal.traverseEs6(compiler, root, finder);

ImmutableList.Builder<ExportInfo> exports = ImmutableList.builder();
Node hoistInsertionReference = null;
if (finder.isCommonJsModule()) {
finder.reportModuleErrors();

Expand All @@ -122,14 +121,14 @@ public void process(Node externs, Node root) {
}
}

hoistInsertionReference = finder.addGoogProvide();
finder.initializeModule();
compiler.reportCodeChange();
}

NodeTraversal.traverseEs6(
compiler,
root,
new RewriteModule(finder.isCommonJsModule(), exports.build(), hoistInsertionReference));
compiler, root, new RewriteModule(finder.isCommonJsModule(), exports.build()));

finder.addGoogProvideAndRequires();
}

/**
Expand Down Expand Up @@ -231,28 +230,9 @@ private boolean removeIIFEWrapper(Node root) {
return true;
}

/**
* Given a scope root, return an insertion reference after any goog.require or goot.provide
* functions.
*/
private static Node getScopeInsertionPoint(Node scopeRoot, Node startPoint) {
Node insertionPoint = startPoint;
for (Node next = startPoint != null ? startPoint.getNext() : scopeRoot.getFirstChild();
next != null
&& next.getFirstChild().isCall()
&& (next.getFirstFirstChild().matchesQualifiedName("goog.require")
|| next.getFirstFirstChild().matchesQualifiedName("goog.provide"));
next = next.getNext()) {
insertionPoint = next;
}

return insertionPoint;
}

/**
* Traverse the script. Find all references to CommonJS require (import) and module.exports or
* export statements. Add goog.require statements for any require statements. Rewrites any require
* calls to reference the rewritten module name.
* export statements. Rewrites any require calls to reference the rewritten module name.
*/
class FindImportsAndExports implements NodeTraversal.Callback {
private boolean hasGoogProvideOrModule = false;
Expand Down Expand Up @@ -399,17 +379,7 @@ private void visitRequireCall(NodeTraversal t, Node require, Node parent) {
parent.getParent().removeChild(parent);
}

if (imports.add(moduleName)) {
if (reportDependencies) {
t.getInput().addRequire(moduleName);
}
this.script.addChildToFront(
IR.exprResult(
IR.call(
IR.getprop(IR.name("goog"), IR.string("require")), IR.string(moduleName)))
.useSourceInfoIfMissingFromForTree(require));
compiler.reportCodeChange();
}
imports.add(moduleName);
}

/**
Expand Down Expand Up @@ -481,33 +451,21 @@ void reportModuleErrors() {
}

/**
* Add a goog.provide statement for the module. If the export is directly assigned more than
* once, or the assignments are not global, declare the module name variable.
* If the export is directly assigned more than once, or the assignments are not global, declare
* the module name variable.
*
* <p>If all of the assignments are simply property assignments, initialize the module name
* variable as a namespace.
*
* <p>Returns a node reference after which hoisted functions within the module should be
* inserted.
*/
Node addGoogProvide() {
void initializeModule() {
CompilerInput ci = compiler.getInput(this.script.getInputId());
ModulePath modulePath = ci.getPath();
if (modulePath == null) {
return null;
return;
}

String moduleName = modulePath.toModuleName();

// Add goog.provide calls.
if (reportDependencies) {
ci.addProvide(moduleName);
}
this.script.addChildToFront(
IR.exprResult(
IR.call(IR.getprop(IR.name("goog"), IR.string("provide")), IR.string(moduleName)))
.useSourceInfoIfMissingFromForTree(this.script));

// The default declaration for the goog.provide is a constant so
// we need to declare the variable if we have more than one
// assignment to module.exports or those assignments are not
Expand Down Expand Up @@ -553,16 +511,50 @@ Node addGoogProvide() {
}
initModule.useSourceInfoIfMissingFromForTree(this.script);

Node refChild = getScopeInsertionPoint(this.script, null);
if (refChild == null) {
this.script.addChildToFront(initModule);
} else {
this.script.addChildAfter(initModule, refChild);
this.script.addChildToFront(initModule);
}
}

/**
* Add goog.require statements for any require statements and a goog.provide statement for the
* module
*/
void addGoogProvideAndRequires() {
CompilerInput ci = compiler.getInput(this.script.getInputId());
ModulePath modulePath = ci.getPath();
if (modulePath == null) {
return;
}

String moduleName = modulePath.toModuleName();

for (String importName : imports) {
// Add goog.provide calls.
if (reportDependencies) {
ci.addRequire(importName);
}
return initModule;

this.script.addChildToFront(
IR.exprResult(
IR.call(
IR.getprop(IR.name("goog"), IR.string("require")), IR.string(importName)))
.useSourceInfoIfMissingFromForTree(this.script));
}

return script.getFirstChild();
if (isCommonJsModule()) {
// Add goog.provide calls.
if (reportDependencies) {
ci.addProvide(moduleName);
}
this.script.addChildToFront(
IR.exprResult(
IR.call(
IR.getprop(IR.name("goog"), IR.string("provide")), IR.string(moduleName)))
.useSourceInfoIfMissingFromForTree(this.script));
compiler.reportCodeChange();
} else if (imports.size() > 0) {
compiler.reportCodeChange();
}
}

/** Find the outermost if node ancestor for a node without leaving the function scope */
Expand Down Expand Up @@ -638,15 +630,10 @@ private class RewriteModule extends AbstractPostOrderCallback {
private final List<Node> imports = new ArrayList<>();
private final List<Node> rewrittenClassExpressions = new ArrayList<>();
private final List<Node> functionsToHoist = new ArrayList<>();
private final Node hoistInsertionPoint;

public RewriteModule(
boolean allowFullRewrite,
ImmutableCollection<ExportInfo> exports,
Node hoistInsertionPoint) {
public RewriteModule(boolean allowFullRewrite, ImmutableCollection<ExportInfo> exports) {
this.allowFullRewrite = allowFullRewrite;
this.exports = exports;
this.hoistInsertionPoint = hoistInsertionPoint;
}

@Override
Expand All @@ -661,17 +648,22 @@ public void visit(NodeTraversal t, Node n, Node parent) {
compiler.reportCodeChange();
}

CompilerInput ci = compiler.getInput(n.getInputId());
ModulePath modulePath = ci.getPath();
String moduleName = modulePath.toModuleName();

// Hoist functions in reverse order so that they maintain the same relative
// order after hoisting.
for (int i = functionsToHoist.size() - 1; i >= 0; i--) {
Node functionExpr = functionsToHoist.get(i);
Node scopeRoot = t.getClosestHoistScope().getRootNode();
Node insertionRef = null;
if (hoistInsertionPoint != null
&& t.getEnclosingFunction() == NodeUtil.getEnclosingFunction(hoistInsertionPoint)) {
insertionRef = hoistInsertionPoint;
Node insertionPoint = scopeRoot.getFirstChild();
if (insertionPoint == null
|| !(insertionPoint.isVar()
&& insertionPoint.getFirstChild().getString().equals(moduleName))) {
insertionPoint = null;
}
Node insertionPoint = getScopeInsertionPoint(scopeRoot, insertionRef);

if (insertionPoint == null) {
if (scopeRoot.getFirstChild() != functionExpr) {
scopeRoot.addChildToFront(functionExpr.detach());
Expand Down

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