com.google.javascript.refactoring.RefasterJsScanner Maven / Gradle / Ivy
/*
* Copyright 2014 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.refactoring;
import static com.google.common.base.Preconditions.checkState;
import static com.google.common.collect.ImmutableList.toImmutableList;
import static java.nio.charset.StandardCharsets.UTF_8;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSortedMap;
import com.google.common.io.Files;
import com.google.common.io.Resources;
import com.google.javascript.jscomp.AbstractCompiler;
import com.google.javascript.jscomp.JsAst;
import com.google.javascript.jscomp.NodeUtil;
import com.google.javascript.jscomp.SourceFile;
import com.google.javascript.jscomp.TypeMatchingStrategy;
import com.google.javascript.rhino.IR;
import com.google.javascript.rhino.JSDocInfo;
import com.google.javascript.rhino.Node;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Stream;
/**
* Class that drives the RefasterJs refactoring by matching against a provided
* template JS file and then applying a transformation based off the template
* JS.
*/
public final class RefasterJsScanner extends Scanner {
/** The JS code that contains the RefasterJs templates. */
private String templateJs;
/**
* The type matching strategy to use when matching templates.
*
* Defaults to {@link TypeMatchingStrategy#SUBTYPES}.
*/
private TypeMatchingStrategy typeMatchingStrategy = TypeMatchingStrategy.SUBTYPES;
/**
* Each 'before' template has multiple RefasterJsTemplate instances that correspond to the
* multiple alternative fixes.
*/
private LinkedHashMap> templates;
/** The RefasterJsTemplates that matched the last match. */
private ImmutableList matchedTemplates;
public RefasterJsScanner() {
this.templateJs = null;
}
/**
* Loads the RefasterJs template. This must be called before the scanner is used.
*/
public void loadRefasterJsTemplate(String refasterjsTemplate) throws IOException {
checkState(
templateJs == null, "Can't load RefasterJs template since a template is already loaded.");
this.templateJs =
Thread.currentThread().getContextClassLoader().getResource(refasterjsTemplate) != null
? Resources.toString(Resources.getResource(refasterjsTemplate), UTF_8)
: Files.asCharSource(new File(refasterjsTemplate), UTF_8).read();
}
/**
* Sets the type matching strategy to use when matching templates.
*
* Defaults to {@link TypeMatchingStrategy#SUBTYPES}.
*/
public void setTypeMatchingStrategy(TypeMatchingStrategy typeMatchingStrategy) {
this.typeMatchingStrategy = typeMatchingStrategy;
}
/**
* Loads the RefasterJs template. This must be called before the scanner is used.
*/
public void loadRefasterJsTemplateFromCode(String refasterJsTemplate) throws IOException {
checkState(
templateJs == null, "Can't load RefasterJs template since a template is already loaded.");
this.templateJs = refasterJsTemplate;
}
/**
* Clears the RefasterJs templates used for comparison. This function should be called if this
* class is going to be used with multiple Compiler objects since type comparison is dependent
* on the compiler used to generate the types.
*/
public void clearTemplates() {
templates = null;
matchedTemplates = null;
}
@Override public boolean matches(Node node, NodeMetadata metadata) {
if (templates == null) {
try {
initialize(metadata.getCompiler());
} catch (Exception e) {
throw new RuntimeException(e);
}
}
matchedTemplates = null;
for (Map.Entry> e : templates.entrySet()) {
if (e.getKey().matches(node, metadata)) {
this.matchedTemplates = e.getValue();
return true;
}
}
return false;
}
@Override
public ImmutableList processMatch(Match match) {
SuggestedFix.Builder defaultFix = null;
for (RefasterJsTemplate matchedTemplate : matchedTemplates) {
SuggestedFix.Builder fix = new SuggestedFix.Builder();
// Only replace the original source with a version serialized from the AST if the after
// template
// is actually different. Otherwise, we might just add churn (e.g. single quotes into double
// quotes and whitespace).
if (matchedTemplate
.beforeTemplate
.getLastChild()
.isEquivalentTo(matchedTemplate.afterTemplate.getLastChild())) {
return ImmutableList.of();
}
Node script = NodeUtil.getEnclosingScript(match.getNode());
ScriptMetadata scriptMetadata = ScriptMetadata.create(script, match.getMetadata());
for (String require : matchedTemplate.getGoogRequiresToAdd()) {
if (scriptMetadata.getAlias(require) == null) {
fix.addGoogRequire(match, require, scriptMetadata);
}
}
// Re-match to compute getTemplateNodeToMatchMap.
Preconditions.checkState(
matchedTemplate.matcher.matches(match.getNode(), match.getMetadata()),
"Matcher for %s did not match a second time",
matchedTemplate.beforeTemplate);
Node newNode =
transformNode(
matchedTemplate.afterTemplate.getLastChild(),
matchedTemplate.matcher.getTemplateNodeToMatchMap(),
scriptMetadata);
Node nodeToReplace = match.getNode();
fix.attachMatchedNodeInfo(nodeToReplace, match.getMetadata().getCompiler());
fix.replace(nodeToReplace, newNode, match.getMetadata().getCompiler());
// If the template is a multiline tcs emplate, make sure to delete the same number of sibling
// nodes as the template has.
Node n = match.getNode().getNext();
int count = matchedTemplate.beforeTemplate.getLastChild().getChildCount();
for (int i = 1; i < count; i++) {
Preconditions.checkNotNull(
n,
"Found mismatched sibling count between before template and matched node.\n"
+ "Template: %s to %s\nMatch: %s",
matchedTemplate.beforeTemplate.getLastChild(),
matchedTemplate.afterTemplate.getLastChild(),
match.getNode());
fix.delete(n);
n = n.getNext();
}
for (String require : matchedTemplate.getGoogRequiresToRemove()) {
fix.removeGoogRequire(match, require);
}
if (defaultFix == null) {
defaultFix = fix;
} else {
defaultFix.addAlternative(fix.build());
}
}
return ImmutableList.of(defaultFix.build());
}
/**
* Transforms the template node to a replacement node by mapping the template names to the ones
* that were matched against in the JsSourceMatcher.
*/
private Node transformNode(
Node templateNode, Map templateNodeToMatchMap, ScriptMetadata scriptMetadata) {
Node clone = templateNode.cloneNode();
if (templateNode.isName()) {
String name = templateNode.getString();
if (templateNodeToMatchMap.containsKey(name)) {
Node templateMatch = templateNodeToMatchMap.get(name);
Preconditions.checkNotNull(templateMatch, "Match for %s is null", name);
if (templateNode.getParent().isVar()) {
// Var declarations should only copy the variable name from the saved match, but the rest
// of the subtree should come from the template node.
clone.setString(templateMatch.getString());
} else {
return templateMatch.cloneTree();
}
}
} else if (templateNode.isCall()
&& templateNode.getBooleanProp(Node.FREE_CALL)
&& templateNode.getFirstChild().isName()) {
String name = templateNode.getFirstChild().getString();
if (templateNodeToMatchMap.containsKey(name)) {
// If this function call matches a template parameter, don't treat it as a free call.
// This mirrors the behavior in the TemplateAstMatcher as well as ensures the code
// generator doesn't generate code like "(0,fn)()".
clone.putBooleanProp(Node.FREE_CALL, false);
}
}
if (templateNode.isQualifiedName()) {
String name = templateNode.getQualifiedName();
String alias = scriptMetadata.getAlias(name);
if (alias != null && !name.equals(alias)) {
return IR.name(alias);
}
}
for (Node child : templateNode.children()) {
clone.addChildToBack(transformNode(child, templateNodeToMatchMap, scriptMetadata));
}
return clone;
}
/**
* Initializes the Scanner class by loading the template JS file, compiling it, and then
* finding all matching RefasterJs template functions in the file.
*/
void initialize(AbstractCompiler compiler) throws Exception {
checkState(
!Strings.isNullOrEmpty(templateJs),
"The template JS must be loaded before the scanner is used. "
+ "Make sure that the template file is not empty.");
Node scriptRoot = new JsAst(SourceFile.fromCode(
"template", templateJs)).getAstRoot(compiler);
// The before-templates are kept in a LinkedHashMap, to ensure that they are later iterated
// over in the order in which they appear in the template JS file.
LinkedHashMap beforeTemplates = new LinkedHashMap<>();
Map> afterTemplates = new HashMap<>();
Set hasChoices = new HashSet<>();
for (Node templateNode : scriptRoot.children()) {
if (templateNode.isFunction()) {
String fnName = templateNode.getFirstChild().getQualifiedName();
if (fnName.startsWith("before_")) {
String templateName = fnName.substring("before_".length());
Preconditions.checkState(
!beforeTemplates.containsKey(templateName),
"Found existing template with the same name: %s", beforeTemplates.get(templateName));
checkState(
templateNode.getLastChild().hasChildren(),
"Before templates are not allowed to be empty!");
beforeTemplates.put(templateName, templateNode);
} else if (fnName.startsWith("after_option_")) {
Matcher m = AFTER_CHOICE_PATTERN.matcher(fnName);
checkState(m.matches(), "Template name %s must match pattern after_option_\\d*_", fnName);
int optionNumber = Integer.parseInt(m.group(1));
String templateName = m.group(2);
if (!afterTemplates.containsKey(templateName)) {
afterTemplates.put(templateName, new TreeMap<>());
hasChoices.add(templateName);
}
checkState(
hasChoices.contains(templateName),
"Template %s can only be mixed with other after_option_ templates");
checkState(
!afterTemplates.get(templateName).containsKey(optionNumber),
"Found duplicate template for %s, assign unique indexes for options",
fnName);
afterTemplates.get(templateName).put(optionNumber, templateNode);
} else if (fnName.startsWith("after_")) {
String templateName = fnName.substring("after_".length());
Preconditions.checkState(
!afterTemplates.containsKey(templateName),
"Found existing template with the same name: %s", afterTemplates.get(templateName));
afterTemplates.put(templateName, ImmutableSortedMap.of(0, templateNode));
} else if (fnName.startsWith("do_not_change_")) {
String templateName = fnName.substring("do_not_change_".length());
Preconditions.checkState(
!beforeTemplates.containsKey(templateName),
"Found existing template with the same name: %s",
beforeTemplates.get(templateName));
Preconditions.checkState(
!afterTemplates.containsKey(templateName),
"Found existing template with the same name: %s",
afterTemplates.get(templateName));
beforeTemplates.put(templateName, templateNode);
afterTemplates.put(templateName, ImmutableSortedMap.of(0, templateNode));
}
}
}
checkState(
!beforeTemplates.isEmpty(),
"Did not find any RefasterJs templates! Make sure that there are 2 functions defined "
+ "with the same name, one with a \"before_\" prefix and one with a \"after_\" prefix");
// TODO(bangert): Get ImmutableLinkedMap into Guava?
this.templates = new LinkedHashMap<>();
for (String templateName : beforeTemplates.keySet()) {
Preconditions.checkState(
afterTemplates.containsKey(templateName) && !afterTemplates.get(templateName).isEmpty(),
"Found before template without at least one corresponding after "
+ " template. Make sure there is an after_%s or after_option_1_%s function defined.",
templateName,
templateName);
ImmutableList.Builder builder = ImmutableList.builder();
for (Node afterTemplateOption : afterTemplates.get(templateName).values()) {
builder.add(
new RefasterJsTemplate(
compiler,
typeMatchingStrategy,
beforeTemplates.get(templateName),
afterTemplateOption));
}
ImmutableList afterOptions = builder.build();
this.templates.put(afterOptions.get(0).matcher, afterOptions);
}
}
private static final Pattern AFTER_CHOICE_PATTERN = Pattern.compile("^after_option_(\\d*)_(.*)");
/** Class that holds the before and after templates for a given RefasterJs refactoring. */
private static class RefasterJsTemplate {
private static final Pattern ADD_GOOG_REQUIRE_PATTERN =
Pattern.compile("\\+require\\s+\\{([^}]+)\\}");
private static final Pattern REMOVE_GOOG_REQUIRE_PATTERN =
Pattern.compile("-require\\s+\\{([^}]+)\\}");
final JsSourceMatcher matcher;
final Node beforeTemplate;
final Node afterTemplate;
RefasterJsTemplate(
AbstractCompiler compiler,
TypeMatchingStrategy typeMatchingStrategy,
Node beforeTemplate,
Node afterTemplate) {
this.matcher = new JsSourceMatcher(compiler, beforeTemplate, typeMatchingStrategy);
this.beforeTemplate = beforeTemplate;
this.afterTemplate = afterTemplate;
}
List getGoogRequiresToAdd() {
return getGoogRequiresFromPattern(ADD_GOOG_REQUIRE_PATTERN);
}
List getGoogRequiresToRemove() {
return getGoogRequiresFromPattern(REMOVE_GOOG_REQUIRE_PATTERN);
}
private ImmutableList getGoogRequiresFromPattern(Pattern pattern) {
return Stream.concat(
getGoogRequiresFromNode(pattern, beforeTemplate).stream(),
getGoogRequiresFromNode(pattern, afterTemplate).stream())
.distinct()
.collect(toImmutableList());
}
private static ImmutableList getGoogRequiresFromNode(
Pattern pattern, Node beforeTemplate) {
JSDocInfo jsDoc = NodeUtil.getBestJSDocInfo(beforeTemplate);
if (jsDoc == null) {
return ImmutableList.of();
}
String jsDocContent = jsDoc.getOriginalCommentString();
if (jsDocContent == null) {
return ImmutableList.of();
}
ImmutableList.Builder requires = ImmutableList.builder();
Matcher m = pattern.matcher(jsDocContent);
while (m.find()) {
requires.add(m.group(1));
}
return requires.build();
}
}
}