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Closure Compiler is a JavaScript optimizing compiler. It parses your
JavaScript, analyzes it, removes dead code and rewrites and minimizes
what's left. It also checks syntax, variable references, and types, and
warns about common JavaScript pitfalls. It is used in many of Google's
JavaScript apps, including Gmail, Google Web Search, Google Maps, and
Google Docs.
/*
* Copyright 2004 The Closure Compiler Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.javascript.jscomp;
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.Ascii;
import com.google.javascript.rhino.IR;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.Token;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Objects;
import javax.annotation.Nullable;
/**
* ReplaceMessages replaces user-visible messages with alternatives.
* It uses Google specific JsMessageVisitor implementation.
*/
@GwtIncompatible("JsMessage")
final class ReplaceMessages extends JsMessageVisitor {
private final MessageBundle bundle;
private final boolean strictReplacement;
static final DiagnosticType BUNDLE_DOES_NOT_HAVE_THE_MESSAGE =
DiagnosticType.error("JSC_BUNDLE_DOES_NOT_HAVE_THE_MESSAGE",
"Message with id = {0} could not be found in replacement bundle");
static final DiagnosticType INVALID_ALTERNATE_MESSAGE_PLACEHOLDERS =
DiagnosticType.error(
"JSC_INVALID_ALTERNATE_MESSAGE_PLACEHOLDERS",
"Alternate message ID={0} placeholders ({1}) differs from {2} placeholders ({3}).");
ReplaceMessages(
AbstractCompiler compiler,
MessageBundle bundle,
boolean checkDuplicatedMessages,
JsMessage.Style style,
boolean strictReplacement) {
super(compiler, checkDuplicatedMessages, style, bundle.idGenerator());
this.bundle = bundle;
this.strictReplacement = strictReplacement;
}
private JsMessage lookupMessage(Node callNode, MessageBundle bundle, JsMessage message) {
JsMessage translatedMessage = bundle.getMessage(message.getId());
if (translatedMessage != null) {
return translatedMessage;
}
String alternateId = message.getAlternateId();
if (alternateId == null) {
return null;
}
JsMessage alternateMessage = bundle.getMessage(alternateId);
if (alternateMessage != null) {
// Validate that the alternate message is compatible with this message. Ideally we'd also
// check meaning and description, but they're not populated by `MessageBundle.getMessage`.
if (!Objects.equals(message.placeholders(), alternateMessage.placeholders())) {
compiler.report(
JSError.make(
callNode,
INVALID_ALTERNATE_MESSAGE_PLACEHOLDERS,
alternateId,
String.valueOf(alternateMessage.placeholders()),
message.getKey(),
String.valueOf(message.placeholders())));
return null;
}
}
return alternateMessage;
}
@Override
void processMessageFallback(
Node callNode, JsMessage message1, JsMessage message2) {
boolean isFirstMessageTranslated = (lookupMessage(callNode, bundle, message1) != null);
boolean isSecondMessageTranslated = (lookupMessage(callNode, bundle, message2) != null);
Node replacementNode =
(isSecondMessageTranslated && !isFirstMessageTranslated)
? callNode.getChildAtIndex(2)
: callNode.getSecondChild();
callNode.replaceWith(replacementNode.detach());
Node changeScope = NodeUtil.getEnclosingChangeScopeRoot(replacementNode);
if (changeScope != null) {
compiler.reportChangeToChangeScope(changeScope);
}
}
@Override
protected void processJsMessage(JsMessage message,
JsMessageDefinition definition) {
// Get the replacement.
Node callNode = definition.getMessageNode();
JsMessage replacement = lookupMessage(callNode, bundle, message);
if (replacement == null) {
if (strictReplacement) {
compiler.report(JSError.make(callNode, BUNDLE_DOES_NOT_HAVE_THE_MESSAGE, message.getId()));
// Fallback to the default message
return;
} else {
// In case if it is not a strict replacement we could leave original
// message.
replacement = message;
}
}
// Replace the message.
Node newValue;
Node msgNode = definition.getMessageNode();
try {
newValue = getNewValueNode(replacement, msgNode);
} catch (MalformedException e) {
compiler.report(JSError.make(
e.getNode(), MESSAGE_TREE_MALFORMED, e.getMessage()));
newValue = msgNode;
}
if (newValue != msgNode) {
newValue.useSourceInfoIfMissingFromForTree(msgNode);
msgNode.replaceWith(newValue);
compiler.reportChangeToEnclosingScope(newValue);
}
}
/**
* Constructs a node representing a message's value, or, if possible, just
* modifies {@code origValueNode} so that it accurately represents the
* message's value.
*
* @param message a message
* @param origValueNode the message's original value node
* @return a Node that can replace {@code origValueNode}
*
* @throws MalformedException if the passed node's subtree structure is
* not as expected
*/
private Node getNewValueNode(JsMessage message, Node origValueNode)
throws MalformedException {
switch (origValueNode.getToken()) {
case FUNCTION:
// The message is a function. Modify the function node.
updateFunctionNode(message, origValueNode);
return origValueNode;
case STRING:
// The message is a simple string. Modify the string node.
String newString = message.toString();
if (!origValueNode.getString().equals(newString)) {
origValueNode.setString(newString);
compiler.reportChangeToEnclosingScope(origValueNode);
}
return origValueNode;
case ADD:
// The message is a simple string. Create a string node.
return IR.string(message.toString());
case CALL:
// The message is a function call. Replace it with a string expression.
return replaceCallNode(message, origValueNode);
default:
throw new MalformedException(
"Expected FUNCTION, STRING, or ADD node; found: " + origValueNode.getToken(),
origValueNode);
}
}
/**
* Updates the descendants of a FUNCTION node to represent a message's value.
*
* The tree looks something like:
*
* function
* |-- name
* |-- lp
* | |-- name
* | -- name
* -- block
* |
* --return
* |
* --add
* |-- string foo
* -- name
*
*
* @param message a message
* @param functionNode the message's original FUNCTION value node
*
* @throws MalformedException if the passed node's subtree structure is
* not as expected
*/
private void updateFunctionNode(JsMessage message, Node functionNode)
throws MalformedException {
checkNode(functionNode, Token.FUNCTION);
Node nameNode = functionNode.getFirstChild();
checkNode(nameNode, Token.NAME);
Node argListNode = nameNode.getNext();
checkNode(argListNode, Token.PARAM_LIST);
Node oldBlockNode = argListNode.getNext();
checkNode(oldBlockNode, Token.BLOCK);
Iterator iterator = message.parts().iterator();
Node valueNode = constructAddOrStringNode(iterator, argListNode);
Node newBlockNode = IR.block(IR.returnNode(valueNode));
if (!newBlockNode.isEquivalentTo(
oldBlockNode,
/* compareType= */ false,
/* recurse= */ true,
/* jsDoc= */ false,
/* sideEffect= */ false)) {
newBlockNode.useSourceInfoIfMissingFromForTree(oldBlockNode);
functionNode.replaceChild(oldBlockNode, newBlockNode);
compiler.reportChangeToEnclosingScope(newBlockNode);
}
}
/**
* Creates a parse tree corresponding to the remaining message parts in
* an iteration. The result will contain only STRING nodes, NAME nodes
* (corresponding to placeholder references), and/or ADD nodes used to
* combine the other two types.
*
* @param partsIterator an iterator over message parts
* @param argListNode a PARAM_LIST node whose children are valid placeholder names
* @return the root of the constructed parse tree
*
* @throws MalformedException if {@code partsIterator} contains a
* placeholder reference that does not correspond to a valid argument in
* the arg list
*/
private static Node constructAddOrStringNode(Iterator partsIterator,
Node argListNode)
throws MalformedException {
if (!partsIterator.hasNext()) {
return IR.string("");
}
CharSequence part = partsIterator.next();
Node partNode = null;
if (part instanceof JsMessage.PlaceholderReference) {
JsMessage.PlaceholderReference phRef =
(JsMessage.PlaceholderReference) part;
for (Node node : argListNode.children()) {
if (node.isName()) {
String arg = node.getString();
// We ignore the case here because the transconsole only supports
// uppercase placeholder names, but function arguments in JavaScript
// code can have mixed case.
if (Ascii.equalsIgnoreCase(arg, phRef.getName())) {
partNode = IR.name(arg);
}
}
}
if (partNode == null) {
throw new MalformedException(
"Unrecognized message placeholder referenced: " + phRef.getName(),
argListNode);
}
} else {
// The part is just a string literal.
partNode = IR.string(part.toString());
}
if (partsIterator.hasNext()) {
return IR.add(partNode,
constructAddOrStringNode(partsIterator, argListNode));
} else {
return partNode;
}
}
/**
* Replaces a CALL node with an inlined message value.
*
* The call tree looks something like:
*
* call
* |-- getprop
* | |-- name 'goog'
* | +-- string 'getMsg'
* |
* |-- string 'Hi {$userName}! Welcome to {$product}.'
* +-- objlit
* |-- string_key 'userName'
* | +-- name 'someUserName'
* +-- string_key 'product'
* +-- call
* +-- name 'getProductName'
*
*
* For that example, we'd return:
*
* add
* |-- string 'Hi '
* +-- add
* |-- name someUserName
* +-- add
* |-- string '! Welcome to '
* +-- add
* |-- call
* | +-- name 'getProductName'
* +-- string '.'
*
* @param message a message
* @param callNode the message's original CALL value node
* @return a STRING node, or an ADD node that does string concatenation, if
* the message has one or more placeholders
*
* @throws MalformedException if the passed node's subtree structure is
* not as expected
*/
private Node replaceCallNode(JsMessage message, Node callNode) throws MalformedException {
checkNode(callNode, Token.CALL);
Node getPropNode = callNode.getFirstChild();
checkNode(getPropNode, Token.GETPROP);
Node stringExprNode = getPropNode.getNext();
checkStringExprNode(stringExprNode);
Node objLitNode = stringExprNode.getNext();
Map options = getOptions(objLitNode != null ? objLitNode.getNext() : null);
// Build the replacement tree.
Iterator iterator = message.parts().iterator();
return iterator.hasNext()
? constructStringExprNode(iterator, objLitNode, options, callNode)
: IR.string("");
}
/**
* Creates a parse tree corresponding to the remaining message parts in an iteration. The result
* consists of one or more STRING nodes, placeholder replacement value nodes (which can be
* arbitrary expressions), and ADD nodes.
*
* @param parts an iterator over message parts
* @param objLitNode an OBJLIT node mapping placeholder names to values
* @return the root of the constructed parse tree
* @throws MalformedException if {@code parts} contains a placeholder reference that does not
* correspond to a valid placeholder name
*/
private static Node constructStringExprNode(
Iterator parts,
@Nullable Node objLitNode,
Map options,
Node refNode)
throws MalformedException {
checkNotNull(refNode);
CharSequence part = parts.next();
Node partNode = null;
if (part instanceof JsMessage.PlaceholderReference) {
JsMessage.PlaceholderReference phRef =
(JsMessage.PlaceholderReference) part;
// The translated message is null
if (objLitNode == null) {
throw new MalformedException(
"Empty placeholder value map for a translated message with placeholders.", refNode);
}
for (Node key = objLitNode.getFirstChild(); key != null;
key = key.getNext()) {
if (key.getString().equals(phRef.getName())) {
Node valueNode = key.getFirstChild();
partNode = valueNode.cloneTree();
}
}
if (partNode == null) {
throw new MalformedException(
"Unrecognized message placeholder referenced: " + phRef.getName(),
objLitNode);
}
} else {
// The part is just a string literal.
String s = part.toString();
if (options.getOrDefault("html", false)) {
// Note that "&" is not replaced because the translation can contain HTML entities.
s = s.replace("<", "<");
}
partNode = IR.string(s);
}
if (parts.hasNext()) {
return IR.add(partNode, constructStringExprNode(parts, objLitNode, options, refNode));
} else {
return partNode;
}
}
private static Map getOptions(@Nullable Node optionsNode)
throws MalformedException {
Map options = new HashMap<>();
if (optionsNode == null) {
return options;
}
if (!optionsNode.isObjectLit()) {
throw new MalformedException("OBJLIT node expected", optionsNode);
}
for (Node aNode = optionsNode.getFirstChild(); aNode != null; aNode = aNode.getNext()) {
if (!aNode.isStringKey()) {
throw new MalformedException("STRING_KEY node expected as OBJLIT key", aNode);
}
String optName = aNode.getString();
Node value = aNode.getFirstChild();
if (!value.isTrue() && !value.isFalse()) {
throw new MalformedException("Literal true or false expected", value);
}
switch (optName) {
case "html":
options.put(optName, value.isTrue());
break;
default:
throw new MalformedException("Unexpected option", aNode);
}
}
return options;
}
/**
* Checks that a node is a valid string expression (either a string literal
* or a concatenation of string literals).
*
* @throws IllegalArgumentException if the node is null or the wrong type
*/
private static void checkStringExprNode(@Nullable Node node) {
if (node == null) {
throw new IllegalArgumentException("Expected a string; found: null");
}
switch (node.getToken()) {
case STRING:
case TEMPLATELIT:
break;
case ADD:
Node c = node.getFirstChild();
checkStringExprNode(c);
checkStringExprNode(c.getNext());
break;
default:
throw new IllegalArgumentException("Expected a string; found: " + node.getToken());
}
}
}