/*******************************************************************************
* Copyright 2011 Google Inc. All Rights Reserved.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* 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.gwt.core.ext.linker.impl;
import com.google.gwt.core.ext.LinkerContext;
import com.google.gwt.core.ext.TreeLogger;
import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.core.ext.linker.AbstractLinker;
import com.google.gwt.core.ext.linker.ArtifactSet;
import com.google.gwt.core.ext.linker.CompilationResult;
import com.google.gwt.core.ext.linker.EmittedArtifact;
import com.google.gwt.core.ext.linker.ScriptReference;
import com.google.gwt.core.ext.linker.SelectionProperty;
import com.google.gwt.core.ext.linker.StylesheetReference;
import com.google.gwt.dev.util.Util;
import com.google.gwt.util.tools.Utility;
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collection;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.SortedSet;
/**
* A base class for Linkers that use an external script to boostrap the GWT
* module. This implementation injects JavaScript Snippets into a JS program
* defined in an external file.
*/
public abstract class SelectionScriptLinker extends AbstractLinker {
/**
* TODO(bobv): Move this class into c.g.g.core.linker when HostedModeLinker
* goes away?
*/
/**
* The extension added to demand-loaded fragment files.
*/
protected static final String FRAGMENT_EXTENSION = ".cache.js";
/**
* A subdirectory to hold all the generated fragments.
*/
protected static final String FRAGMENT_SUBDIR = "deferredjs";
/**
* Determines whether or not the URL is relative.
*
* @param src the test url
* @return <code>true</code> if the URL is relative, <code>false</code> if not
*/
@SuppressWarnings("unused")
protected static boolean isRelativeURL(String src) {
// A straight absolute url for the same domain, server, and protocol.
if (src.startsWith("/")) {
return false;
}
// If it can be parsed as a URL, then it's probably absolute.
try {
// Just check to see if it can be parsed, no need to store the result.
new URL(src);
// Let's guess that it is absolute (thus, not relative).
return false;
} catch (MalformedURLException e) {
// Do nothing, since it was a speculative parse.
}
// Since none of the above matched, let's guess that it's relative.
return true;
}
protected static void replaceAll(StringBuffer buf, String search,
String replace) {
int len = search.length();
for (int pos = buf.indexOf(search); pos >= 0; pos = buf.indexOf(search,
pos + 1)) {
buf.replace(pos, pos + len, replace);
}
}
private final Map<CompilationResult, String> compilationStrongNames = new IdentityHashMap<CompilationResult, String>();
@Override
public ArtifactSet link(TreeLogger logger, LinkerContext context,
ArtifactSet artifacts) throws UnableToCompleteException {
ArtifactSet toReturn = new ArtifactSet(artifacts);
for (CompilationResult compilation : toReturn.find(CompilationResult.class)) {
toReturn.addAll(doEmitCompilation(logger, context, compilation));
}
toReturn.add(emitSelectionScript(logger, context, artifacts));
return toReturn;
}
protected Collection<EmittedArtifact> doEmitCompilation(TreeLogger logger,
LinkerContext context, CompilationResult result)
throws UnableToCompleteException {
String[] js = result.getJavaScript();
byte[][] bytes = new byte[js.length][];
bytes[0] = generatePrimaryFragment(logger, context, result, js);
for (int i = 1; i < js.length; i++) {
bytes[i] = Util.getBytes(js[i]);
}
Collection<EmittedArtifact> toReturn = new ArrayList<EmittedArtifact>();
toReturn.add(emitBytes(logger, bytes[0], result.getStrongName()
+ getCompilationExtension(logger, context)));
for (int i = 1; i < js.length; i++) {
toReturn.add(emitBytes(logger, bytes[i], FRAGMENT_SUBDIR + File.separator
+ result.getStrongName() + File.separator + i + FRAGMENT_EXTENSION));
}
compilationStrongNames.put(result, result.getStrongName());
return toReturn;
}
protected EmittedArtifact emitSelectionScript(TreeLogger logger,
LinkerContext context, ArtifactSet artifacts)
throws UnableToCompleteException {
String selectionScript = generateSelectionScript(logger, context, artifacts);
selectionScript = context.optimizeJavaScript(logger, selectionScript);
/*
* Last modified is important to keep hosted mode refreses from clobbering
* web mode compiles. We set the timestamp on the hosted mode selection
* script to the same mod time as the module (to allow updates). For web
* mode, we just set it to now.
*/
long lastModified;
if (artifacts.find(CompilationResult.class).size() == 0) {
lastModified = context.getModuleLastModified();
} else {
lastModified = System.currentTimeMillis();
}
return emitString(logger, selectionScript, context.getModuleName()
+ ".nocache.js", lastModified);
}
/**
* Generate the primary fragment. The default implementation is based on
* {@link #getModulePrefix(TreeLogger, LinkerContext, String, int)} and
* {@link #getModuleSuffix(TreeLogger, LinkerContext)}.
*/
protected byte[] generatePrimaryFragment(TreeLogger logger,
LinkerContext context, CompilationResult result, String[] js)
throws UnableToCompleteException {
StringBuffer b = new StringBuffer();
b.append(getModulePrefix(logger, context, result.getStrongName(), js.length));
b.append(js[0]);
b.append(getModuleSuffix(logger, context));
return Util.getBytes(b.toString());
}
protected String generatePropertyProvider(SelectionProperty prop) {
StringBuffer toReturn = new StringBuffer();
if (prop.tryGetValue() == null && !prop.isDerived()) {
toReturn.append("providers['" + prop.getName() + "'] = function()");
toReturn.append(prop.getPropertyProvider());
toReturn.append(";");
toReturn.append("values['" + prop.getName() + "'] = {");
boolean needsComma = false;
int counter = 0;
for (String value : prop.getPossibleValues()) {
if (needsComma) {
toReturn.append(",");
} else {
needsComma = true;
}
toReturn.append("'" + value + "':");
toReturn.append(counter++);
}
toReturn.append("};");
}
return toReturn.toString();
}
protected String generateScriptInjector(String scriptUrl) {
if (isRelativeURL(scriptUrl)) {
return " if (!__gwt_scriptsLoaded['"
+ scriptUrl
+ "']) {\n"
+ " __gwt_scriptsLoaded['"
+ scriptUrl
+ "'] = true;\n"
+ " document.write('<script language=\\\"javascript\\\" src=\\\"'+base+'"
+ scriptUrl + "\\\"></script>');\n" + " }\n";
} else {
return " if (!__gwt_scriptsLoaded['" + scriptUrl + "']) {\n"
+ " __gwt_scriptsLoaded['" + scriptUrl + "'] = true;\n"
+ " document.write('<script language=\\\"javascript\\\" src=\\\""
+ scriptUrl + "\\\"></script>');\n" + " }\n";
}
}
protected String generateSelectionScript(TreeLogger logger,
LinkerContext context, ArtifactSet artifacts)
throws UnableToCompleteException {
StringBuffer selectionScript;
try {
selectionScript = new StringBuffer(
Utility.getFileFromClassPath(getSelectionScriptTemplate(logger,
context)));
} catch (IOException e) {
logger.log(TreeLogger.ERROR, "Unable to read selection script template",
e);
throw new UnableToCompleteException();
}
replaceAll(selectionScript, "__MODULE_FUNC__",
context.getModuleFunctionName());
replaceAll(selectionScript, "__MODULE_NAME__", context.getModuleName());
int startPos;
// Add external dependencies
startPos = selectionScript.indexOf("// __MODULE_STYLES_END__");
if (startPos != -1) {
for (StylesheetReference resource : artifacts.find(StylesheetReference.class)) {
String text = generateStylesheetInjector(resource.getSrc());
selectionScript.insert(startPos, text);
startPos += text.length();
}
}
startPos = selectionScript.indexOf("// __MODULE_SCRIPTS_END__");
if (startPos != -1) {
for (ScriptReference resource : artifacts.find(ScriptReference.class)) {
String text = generateScriptInjector(resource.getSrc());
selectionScript.insert(startPos, text);
startPos += text.length();
}
}
// Add property providers
startPos = selectionScript.indexOf("// __PROPERTIES_END__");
if (startPos != -1) {
for (SelectionProperty p : context.getProperties()) {
String text = generatePropertyProvider(p);
selectionScript.insert(startPos, text);
startPos += text.length();
}
}
// Possibly add permutations
SortedSet<CompilationResult> compilations = artifacts.find(CompilationResult.class);
startPos = selectionScript.indexOf("// __PERMUTATIONS_END__");
if (startPos != -1) {
StringBuffer text = new StringBuffer();
if (compilations.size() == 0) {
// Hosted mode link.
text.append("alert(\"GWT module '"
+ context.getModuleName()
+ "' may need to be (re)compiled\");");
text.append("return;");
} else if (compilations.size() == 1) {
// Just one distinct compilation; no need to evaluate properties
Iterator<CompilationResult> iter = compilations.iterator();
CompilationResult result = iter.next();
text.append("strongName = '" + compilationStrongNames.get(result)
+ "';");
} else {
for (CompilationResult r : compilations) {
for (Map<SelectionProperty, String> propertyMap : r.getPropertyMap()) {
// unflatten([v1, v2, v3], 'strongName');
text.append("unflattenKeylistIntoAnswers([");
boolean needsComma = false;
for (SelectionProperty p : context.getProperties()) {
if (!propertyMap.containsKey(p)) {
continue;
}
if (needsComma) {
text.append(",");
} else {
needsComma = true;
}
text.append("'" + propertyMap.get(p) + "'");
}
text.append("], '").append(compilationStrongNames.get(r)).append(
"');\n");
}
}
// strongName = answers[compute('p1')][compute('p2')];
text.append("strongName = answers[");
boolean needsIndexMarkers = false;
for (SelectionProperty p : context.getProperties()) {
if (p.tryGetValue() != null) {
continue;
} else if (p.isDerived()) {
continue;
}
if (needsIndexMarkers) {
text.append("][");
} else {
needsIndexMarkers = true;
}
text.append("computePropValue('" + p.getName() + "')");
}
text.append("];");
}
selectionScript.insert(startPos, text);
}
return selectionScript.toString();
}
/**
* Generate a Snippet of JavaScript to inject an external stylesheet.
*
* <pre>
* if (!__gwt_stylesLoaded['URL']) {
* var l = $doc.createElement('link');
* __gwt_styleLoaded['URL'] = l;
* l.setAttribute('rel', 'stylesheet');
* l.setAttribute('href', HREF_EXPR);
* $doc.getElementsByTagName('head')[0].appendChild(l);
* }
* </pre>
*/
protected String generateStylesheetInjector(String stylesheetUrl) {
String hrefExpr = "'" + stylesheetUrl + "'";
if (isRelativeURL(stylesheetUrl)) {
hrefExpr = "base + " + hrefExpr;
}
return "if (!__gwt_stylesLoaded['" + stylesheetUrl + "']) {\n "
+ " var l = $doc.createElement('link');\n "
+ " __gwt_stylesLoaded['" + stylesheetUrl + "'] = l;\n "
+ " l.setAttribute('rel', 'stylesheet');\n "
+ " l.setAttribute('href', " + hrefExpr + ");\n "
+ " $doc.getElementsByTagName('head')[0].appendChild(l);\n "
+ "}\n";
}
protected abstract String getCompilationExtension(TreeLogger logger,
LinkerContext context) throws UnableToCompleteException;
/**
* Get the partial path on which a CompilationResult has been emitted.
*
* @return the partial path, or <code>null</code> if the CompilationResult has
* not been emitted.
*/
protected String getCompilationStrongName(CompilationResult result) {
return compilationStrongNames.get(result);
}
/**
* Compute the beginning of a JavaScript file that will hold the main module
* implementation.
*/
protected abstract String getModulePrefix(TreeLogger logger,
LinkerContext context, String strongName)
throws UnableToCompleteException;
/**
* Compute the beginning of a JavaScript file that will hold the main module
* implementation. By default, calls
* {@link #getModulePrefix(TreeLogger, LinkerContext, String)}.
*
* @param strongName strong name of the module being emitted
* @param numFragments the number of fragments for this module, including the
* main fragment (fragment 0)
*/
protected String getModulePrefix(TreeLogger logger, LinkerContext context,
String strongName, int numFragments) throws UnableToCompleteException {
return getModulePrefix(logger, context, strongName);
}
protected abstract String getModuleSuffix(TreeLogger logger,
LinkerContext context) throws UnableToCompleteException;
protected abstract String getSelectionScriptTemplate(TreeLogger logger,
LinkerContext context) throws UnableToCompleteException;
}