dev/codeserver/java/com/google/gwt/dev/codeserver/Recompiler.java - gwt - Git at Google

 /*
  * Copyright 2011 Google Inc.
  *
  * 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.gwt.dev.codeserver;

 import com.google.gwt.core.ext.Linker;
 import com.google.gwt.core.ext.TreeLogger;
 import com.google.gwt.core.ext.TreeLogger.Type;
 import com.google.gwt.core.ext.UnableToCompleteException;
 import com.google.gwt.core.linker.CrossSiteIframeLinker;
 import com.google.gwt.core.linker.IFrameLinker;
 import com.google.gwt.dev.Compiler;
 import com.google.gwt.dev.CompilerContext;
 import com.google.gwt.dev.CompilerOptions;
 import com.google.gwt.dev.IncrementalBuilder;
 import com.google.gwt.dev.IncrementalBuilder.BuildResultStatus;
 import com.google.gwt.dev.MinimalRebuildCache;
 import com.google.gwt.dev.cfg.BindingProperty;
 import com.google.gwt.dev.cfg.ConfigProps;
 import com.google.gwt.dev.cfg.ConfigurationProperty;
 import com.google.gwt.dev.cfg.ModuleDef;
 import com.google.gwt.dev.cfg.ModuleDefLoader;
 import com.google.gwt.dev.cfg.ResourceLoader;
 import com.google.gwt.dev.cfg.ResourceLoaders;
 import com.google.gwt.dev.javac.UnitCacheSingleton;
 import com.google.gwt.dev.resource.impl.ResourceOracleImpl;
 import com.google.gwt.dev.resource.impl.ZipFileClassPathEntry;
 import com.google.gwt.dev.util.log.CompositeTreeLogger;
 import com.google.gwt.dev.util.log.PrintWriterTreeLogger;
 import com.google.gwt.thirdparty.guava.common.base.Joiner;
 import com.google.gwt.thirdparty.guava.common.collect.ImmutableMap;
 import com.google.gwt.thirdparty.guava.common.collect.Maps;

 import java.io.File;
 import java.io.IOException;
 import java.util.Map;
 import java.util.Objects;
 import java.util.concurrent.atomic.AtomicReference;

 /**
  * Recompiles a GWT module on demand.
  */
 class Recompiler {

   private final AppSpace appSpace;
   private final String originalModuleName;
   private IncrementalBuilder incrementalBuilder;
   private final TreeLogger logger;
   private String serverPrefix;
   private int compilesDone = 0;
   private MinimalRebuildCache minimalRebuildCache;

   // after renaming
   private AtomicReference<String> moduleName = new AtomicReference<String>(null);

   private final AtomicReference<CompileDir> lastBuild = new AtomicReference<CompileDir>();

   private InputSummary lastBuildInput;

   private CompileDir publishedCompileDir;
   private final AtomicReference<ResourceLoader> resourceLoader =
       new AtomicReference<ResourceLoader>();
   private final CompilerContext.Builder compilerContextBuilder = new CompilerContext.Builder();
   private CompilerContext compilerContext;
   private Options options;

   Recompiler(AppSpace appSpace, String moduleName, Options options, TreeLogger logger) {
     this.appSpace = appSpace;
     this.originalModuleName = moduleName;
     this.options = options;
     this.logger = logger;
     this.serverPrefix = options.getPreferredHost() + ":" + options.getPort();
     compilerContext = compilerContextBuilder.build();
   }

   CompileDir recompile(Map<String, String> bindingProperties, AtomicReference<Progress> progress)
       throws UnableToCompleteException {
     if (options.shouldCompilePerFile()) {
       return compile(bindingProperties, progress, minimalRebuildCache);
     }
     return compile(bindingProperties, progress, new MinimalRebuildCache());
   }

   synchronized CompileDir compile(Map<String, String> bindingProperties,
       AtomicReference<Progress> progress) throws UnableToCompleteException {
     return compile(bindingProperties, progress, new MinimalRebuildCache());
   }

   private synchronized CompileDir compile(Map<String, String> bindingProperties,
       AtomicReference<Progress> progress, MinimalRebuildCache minimalRebuildCache)
       throws UnableToCompleteException {
     if (compilesDone == 0) {
       System.setProperty("java.awt.headless", "true");
       if (System.getProperty("gwt.speedtracerlog") == null) {
         System.setProperty("gwt.speedtracerlog",
             appSpace.getSpeedTracerLogFile().getAbsolutePath());
       }
       compilerContext = compilerContextBuilder.unitCache(
           UnitCacheSingleton.get(logger, appSpace.getUnitCacheDir())).build();
     }

     long startTime = System.currentTimeMillis();
     int compileId = ++compilesDone;
     CompileDir compileDir = makeCompileDir(compileId);
     TreeLogger compileLogger = makeCompileLogger(compileDir);

     boolean listenerFailed = false;
     try {
       options.getRecompileListener().startedCompile(originalModuleName, compileId, compileDir);
     } catch (Exception e) {
       compileLogger.log(TreeLogger.Type.WARN, "listener threw exception", e);
       listenerFailed = true;
     }

     boolean success = false;
     try {
       if (options.shouldCompileIncremental()) {
         // Just have one message for now.
         progress.set(new Progress.Compiling(moduleName.get(), compilesDone, 0, 1, "Compiling"));

         success = compileIncremental(compileLogger, compileDir);
       } else {
         success = compileMonolithic(compileLogger, bindingProperties, compileDir, progress,
             minimalRebuildCache);
       }
     } finally {
       try {
         options.getRecompileListener().finishedCompile(originalModuleName, compilesDone, success);
       } catch (Exception e) {
         compileLogger.log(TreeLogger.Type.WARN, "listener threw exception", e);
         listenerFailed = true;
       }
     }

     if (!success) {
       compileLogger.log(TreeLogger.Type.ERROR, "Compiler returned false");
       throw new UnableToCompleteException();
     }

     // keep the minimal rebuild cache for the next compile
     this.minimalRebuildCache = minimalRebuildCache;

     long elapsedTime = System.currentTimeMillis() - startTime;
     compileLogger.log(TreeLogger.Type.INFO,
         String.format("%.3fs total -- Compile completed", elapsedTime / 1000d));

     if (options.isCompileTest() && listenerFailed) {
       throw new UnableToCompleteException();
     }

     return publishedCompileDir;
   }

   synchronized CompileDir noCompile() throws UnableToCompleteException {
     long startTime = System.currentTimeMillis();
     CompileDir compileDir = makeCompileDir(++compilesDone);
     TreeLogger compileLogger = makeCompileLogger(compileDir);

     ModuleDef module = loadModule(compileLogger);
     String newModuleName = module.getName();  // includes any rename.
     moduleName.set(newModuleName);

     lastBuild.set(compileDir);

     try {
       // Prepare directory.
       File outputDir = new File(
           compileDir.getWarDir().getCanonicalPath() + "/" + getModuleName());
       if (!outputDir.exists()) {
         if (!outputDir.mkdir()) {
           compileLogger.log(TreeLogger.Type.WARN, "cannot create directory: " + outputDir);
         }
       }

       // Creates a "module_name.nocache.js" that just forces a recompile.
       String moduleScript = PageUtil.loadResource(Recompiler.class, "nomodule.nocache.js");
       moduleScript = moduleScript.replace("__MODULE_NAME__", getModuleName());
       PageUtil.writeFile(outputDir.getCanonicalPath() + "/" + getModuleName() + ".nocache.js",
           moduleScript);

     } catch (IOException e) {
       compileLogger.log(TreeLogger.Type.ERROR, "Error creating uncompiled module.", e);
     }
     long elapsedTime = System.currentTimeMillis() - startTime;
     compileLogger.log(TreeLogger.Type.INFO, "Module setup completed in " + elapsedTime + " ms");
     return compileDir;
   }

   private boolean compileIncremental(TreeLogger compileLogger, CompileDir compileDir) {
     BuildResultStatus buildResultStatus;
     // Perform a compile.
     if (incrementalBuilder == null) {
       // If it's the first compile.
       ResourceLoader resources = ResourceLoaders.forClassLoader(Thread.currentThread());
       resources = ResourceLoaders.forPathAndFallback(options.getSourcePath(), resources);
       this.resourceLoader.set(resources);

       incrementalBuilder = new IncrementalBuilder(originalModuleName,
           compileDir.getWarDir().getPath(), compileDir.getWorkDir().getPath(),
           compileDir.getGenDir().getPath(), resourceLoader.get());
       buildResultStatus = incrementalBuilder.build(compileLogger);
     } else {
       // If it's a rebuild.
       incrementalBuilder.setWarDir(compileDir.getWarDir().getPath());
       buildResultStatus = incrementalBuilder.rebuild(compileLogger);
     }

     if (incrementalBuilder.isRootModuleKnown()) {
       moduleName.set(incrementalBuilder.getRootModuleName());
     }
     // Unlike a monolithic compile, the incremental builder can successfully build but have no new
     // output (for example when no files have changed). So it's important to only publish the new
     // compileDir if it actually contains output.
     if (buildResultStatus.isSuccess() && buildResultStatus.outputChanged()) {
       publishedCompileDir = compileDir;
     }
     lastBuild.set(compileDir); // makes compile log available over HTTP

     return buildResultStatus.isSuccess();
   }

   private boolean compileMonolithic(TreeLogger compileLogger, Map<String, String> bindingProperties,
       CompileDir compileDir, AtomicReference<Progress> progress, MinimalRebuildCache rebuildCache)
       throws UnableToCompleteException {

     progress.set(new Progress.Compiling(moduleName.get(), compilesDone, 0, 2, "Loading modules"));

     CompilerOptions loadOptions = new CompilerOptionsImpl(compileDir, originalModuleName, options);
     compilerContext = compilerContextBuilder.options(loadOptions).build();

     ModuleDef module = loadModule(compileLogger);
     bindingProperties = restrictPermutations(logger, module, bindingProperties);

     // Propagates module rename.
     String newModuleName = module.getName();
     moduleName.set(newModuleName);

     // Check if we can skip the compile altogether.
     InputSummary input = new InputSummary(bindingProperties, module);
     if (input.equals(lastBuildInput)) {
       compileLogger.log(Type.INFO, "skipped compile because no input files have changed");
       return true;
     }

     progress.set(new Progress.Compiling(newModuleName, compilesDone, 1, 2, "Compiling"));
     // TODO: use speed tracer to get more compiler events?

     CompilerOptions runOptions = new CompilerOptionsImpl(compileDir, newModuleName, options);
     compilerContext = compilerContextBuilder.options(runOptions).build();

     boolean success = new Compiler(runOptions, rebuildCache).run(compileLogger, module);
     if (success) {
       publishedCompileDir = compileDir;
       lastBuildInput = input;
     } else {
       // always recompile after an error
       lastBuildInput = null;
     }
     lastBuild.set(compileDir); // makes compile log available over HTTP

     return success;
   }

   /**
    * Returns the log from the last compile. (It may be a failed build.)
    */
   File getLastLog() {
     return lastBuild.get().getLogFile();
   }

   String getModuleName() {
     return moduleName.get();
   }

   ResourceLoader getResourceLoader() {
     return resourceLoader.get();
   }

   private TreeLogger makeCompileLogger(CompileDir compileDir)
       throws UnableToCompleteException {
     try {
       PrintWriterTreeLogger fileLogger =
           new PrintWriterTreeLogger(compileDir.getLogFile());
       fileLogger.setMaxDetail(options.getLogLevel());
       return new CompositeTreeLogger(logger, fileLogger);
     } catch (IOException e) {
       logger.log(TreeLogger.ERROR, "unable to open log file: " + compileDir.getLogFile(), e);
       throw new UnableToCompleteException();
     }
   }

   /**
    * Loads the module and configures it for SuperDevMode. (Does not restrict permutations.)
    */
   private ModuleDef loadModule(TreeLogger logger) throws UnableToCompleteException {

     // make sure we get the latest version of any modified jar
     ZipFileClassPathEntry.clearCache();
     ResourceOracleImpl.clearCache();

     ResourceLoader resources = ResourceLoaders.forClassLoader(Thread.currentThread());
     resources = ResourceLoaders.forPathAndFallback(options.getSourcePath(), resources);
     this.resourceLoader.set(resources);

     // ModuleDefLoader.loadFromResources() checks for modified .gwt.xml files.
     ModuleDef moduleDef = ModuleDefLoader.loadFromResources(
         logger, compilerContext, originalModuleName, resources, true);
     compilerContext = compilerContextBuilder.module(moduleDef).build();

     // A snapshot of the module's configuration before we modified it.
     ConfigProps config = new ConfigProps(moduleDef);

     // We need a cross-site linker. Automatically replace the default linker.
     if (IFrameLinker.class.isAssignableFrom(moduleDef.getActivePrimaryLinker())) {
       moduleDef.addLinker("xsiframe");
     }

     // Check that we have a compatible linker.
     Class<? extends Linker> linker = moduleDef.getActivePrimaryLinker();
     if (!CrossSiteIframeLinker.class.isAssignableFrom(linker)) {
       logger.log(TreeLogger.ERROR,
           "linkers other than CrossSiteIFrameLinker aren't supported. Found: " + linker.getName());
       throw new UnableToCompleteException();
     }

     // Print a nice error if the superdevmode hook isn't present
     if (config.getStrings("devModeRedirectEnabled").isEmpty()) {
       throw new RuntimeException("devModeRedirectEnabled isn't set for module: " +
           moduleDef.getName());
     }

     // Disable the redirect hook here to make sure we don't have an infinite loop.
     // (There is another check in the JavaScript, but just in case.)
     overrideConfig(moduleDef, "devModeRedirectEnabled", "false");

     // Turn off "installCode" if it's on because it makes debugging harder.
     // (If it's already off, don't change anything.)
     if (config.getBoolean("installCode", true)) {
       overrideConfig(moduleDef, "installCode", "false");
       // Make sure installScriptJs is set to the default for compiling without installCode.
       overrideConfig(moduleDef, "installScriptJs",
           "com/google/gwt/core/ext/linker/impl/installScriptDirect.js");
     }

     // override computeScriptBase.js to enable the "Compile" button
     overrideConfig(moduleDef, "computeScriptBaseJs",
         "com/google/gwt/dev/codeserver/computeScriptBase.js");
     // Fix bug with SDM and Chrome 24+ where //@ sourceURL directives cause X-SourceMap header to be ignored
     // Frustratingly, Chrome won't canonicalize a relative URL
     overrideConfig(moduleDef, "includeSourceMapUrl", "http://" + serverPrefix +
         WebServer.sourceMapLocationForModule(moduleDef.getName()));

     // If present, set some config properties back to defaults.
     // (Needed for Google's server-side linker.)
     maybeOverrideConfig(moduleDef, "includeBootstrapInPrimaryFragment", "false");
     maybeOverrideConfig(moduleDef, "permutationsJs",
         "com/google/gwt/core/ext/linker/impl/permutations.js");
     maybeOverrideConfig(moduleDef, "propertiesJs",
         "com/google/gwt/core/ext/linker/impl/properties.js");

     overrideBinding(moduleDef, "compiler.useSourceMaps", "true");
     overrideBinding(moduleDef, "superdevmode", "on");
     return moduleDef;
   }

   /**
    * Restricts the compiled permutations by applying the given binding properties, if possible.
    * In some cases, a different binding may be chosen instead.
    * @return a map of the actual properties used.
    */
   private Map<String, String> restrictPermutations(TreeLogger logger, ModuleDef moduleDef,
       Map<String, String> bindingProperties) {

     Map<String, String> chosenProps = Maps.newHashMap();

     for (Map.Entry<String, String> entry : bindingProperties.entrySet()) {
       String propName = entry.getKey();
       String propValue = entry.getValue();
       String actual = maybeSetBinding(logger, moduleDef, propName, propValue);
       if (actual != null) {
         chosenProps.put(propName, actual);
       }
     }

     return chosenProps;
   }

   /**
    * Attempts to set a binding property to the given value.
    * If the value is not allowed, see if we can find a value that will work.
    * There is a special case for "locale".
    * @return the value actually set, or null if unable to set the property
    */
   private static String maybeSetBinding(TreeLogger logger, ModuleDef module, String propName,
       String newValue) {

     logger = logger.branch(TreeLogger.Type.INFO, "binding: " + propName + "=" + newValue);

     BindingProperty binding = module.getProperties().findBindingProp(propName);
     if (binding == null) {
       logger.log(TreeLogger.Type.WARN, "undefined property: '" + propName + "'");
       return null;
     }

     if (!binding.isAllowedValue(newValue)) {

       String[] allowedValues = binding.getAllowedValues(binding.getRootCondition());
       logger.log(TreeLogger.Type.WARN, "property '" + propName +
           "' cannot be set to '" + newValue + "'");
       logger.log(TreeLogger.Type.INFO, "allowed values: " +
           Joiner.on(", ").join(allowedValues));

       // See if we can fall back on a reasonable default.
       if (allowedValues.length == 1) {
         // There is only one possibility, so use it.
         newValue = allowedValues[0];
       } else if (binding.getName().equals("locale")) {
         // TODO: come up with a more general solution. Perhaps fail
         // the compile and give the user a way to override the property?
         newValue = chooseDefault(binding, "default", "en", "en_US");
       } else {
         // There is more than one. Continue and possibly compile multiple permutations.
         logger.log(TreeLogger.Type.INFO, "continuing without " + propName +
             ". Sourcemaps may not work.");
         return null;
       }

       logger.log(TreeLogger.Type.INFO, "recovered with " + propName + "=" + newValue);
     }

     binding.setAllowedValues(binding.getRootCondition(), newValue);
     return newValue;
   }

   private static String chooseDefault(BindingProperty property, String... candidates) {
     for (String candidate : candidates) {
       if (property.isAllowedValue(candidate)) {
         return candidate;
       }
     }
     return property.getFirstLegalValue();
   }

   /**
    * Sets a binding even if it's set to a different value in the GWT application.
    */
   private static void overrideBinding(ModuleDef module, String propName, String newValue) {
     BindingProperty binding = module.getProperties().findBindingProp(propName);
     if (binding != null) {
       binding.setAllowedValues(binding.getRootCondition(), newValue);
     }
   }

   private static boolean maybeOverrideConfig(ModuleDef module, String propName, String newValue) {
     ConfigurationProperty config = module.getProperties().findConfigProp(propName);
     if (config != null) {
       config.setValue(newValue);
       return true;
     }
     return false;
   }

   private static void overrideConfig(ModuleDef module, String propName, String newValue) {
     if (!maybeOverrideConfig(module, propName, newValue)) {
       throw new RuntimeException("not found: " + propName);
     }
   }

   private CompileDir makeCompileDir(int compileId)
       throws UnableToCompleteException {
     return CompileDir.create(appSpace.getCompileDir(compileId), logger);
   }

   /**
    * Summarizes the inputs to a GWT compile. (Immutable.)
    * Two summaries should be equal if the compiler's inputs are equal (with high probability).
    */
   private static class InputSummary {
     private final ImmutableMap<String, String> bindingProperties;
     private final long moduleLastModified;
     private final long resourcesLastModified;
     private final long filenameHash;

     InputSummary(Map<String, String> bindingProperties, ModuleDef module) {
       this.bindingProperties = ImmutableMap.copyOf(bindingProperties);
       this.moduleLastModified = module.lastModified();
       this.resourcesLastModified = module.getResourceLastModified();
       this.filenameHash = module.getInputFilenameHash();
     }

     @Override
     public boolean equals(Object obj) {
       if (obj instanceof InputSummary) {
         InputSummary other = (InputSummary) obj;
         return bindingProperties.equals(other.bindingProperties) &&
             moduleLastModified == other.moduleLastModified &&
             resourcesLastModified == other.resourcesLastModified &&
             filenameHash == other.filenameHash;
       }
       return false;
     }

     @Override
     public int hashCode() {
       return Objects.hash(bindingProperties, moduleLastModified, resourcesLastModified,
           filenameHash);
     }
   }
 }
	/*
	* Copyright 2011 Google Inc.
	*
	* 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.gwt.dev.codeserver;

	import com.google.gwt.core.ext.Linker;
	import com.google.gwt.core.ext.TreeLogger;
	import com.google.gwt.core.ext.TreeLogger.Type;
	import com.google.gwt.core.ext.UnableToCompleteException;
	import com.google.gwt.core.linker.CrossSiteIframeLinker;
	import com.google.gwt.core.linker.IFrameLinker;
	import com.google.gwt.dev.Compiler;
	import com.google.gwt.dev.CompilerContext;
	import com.google.gwt.dev.CompilerOptions;
	import com.google.gwt.dev.IncrementalBuilder;
	import com.google.gwt.dev.IncrementalBuilder.BuildResultStatus;
	import com.google.gwt.dev.MinimalRebuildCache;
	import com.google.gwt.dev.cfg.BindingProperty;
	import com.google.gwt.dev.cfg.ConfigProps;
	import com.google.gwt.dev.cfg.ConfigurationProperty;
	import com.google.gwt.dev.cfg.ModuleDef;
	import com.google.gwt.dev.cfg.ModuleDefLoader;
	import com.google.gwt.dev.cfg.ResourceLoader;
	import com.google.gwt.dev.cfg.ResourceLoaders;
	import com.google.gwt.dev.javac.UnitCacheSingleton;
	import com.google.gwt.dev.resource.impl.ResourceOracleImpl;
	import com.google.gwt.dev.resource.impl.ZipFileClassPathEntry;
	import com.google.gwt.dev.util.log.CompositeTreeLogger;
	import com.google.gwt.dev.util.log.PrintWriterTreeLogger;
	import com.google.gwt.thirdparty.guava.common.base.Joiner;
	import com.google.gwt.thirdparty.guava.common.collect.ImmutableMap;
	import com.google.gwt.thirdparty.guava.common.collect.Maps;

	import java.io.File;
	import java.io.IOException;
	import java.util.Map;
	import java.util.Objects;
	import java.util.concurrent.atomic.AtomicReference;

	/**
	* Recompiles a GWT module on demand.
	*/
	class Recompiler {

	private final AppSpace appSpace;
	private final String originalModuleName;
	private IncrementalBuilder incrementalBuilder;
	private final TreeLogger logger;
	private String serverPrefix;
	private int compilesDone = 0;
	private MinimalRebuildCache minimalRebuildCache;

	// after renaming
	private AtomicReference<String> moduleName = new AtomicReference<String>(null);

	private final AtomicReference<CompileDir> lastBuild = new AtomicReference<CompileDir>();

	private InputSummary lastBuildInput;

	private CompileDir publishedCompileDir;
	private final AtomicReference<ResourceLoader> resourceLoader =
	new AtomicReference<ResourceLoader>();
	private final CompilerContext.Builder compilerContextBuilder = new CompilerContext.Builder();
	private CompilerContext compilerContext;
	private Options options;

	Recompiler(AppSpace appSpace, String moduleName, Options options, TreeLogger logger) {
	this.appSpace = appSpace;
	this.originalModuleName = moduleName;
	this.options = options;
	this.logger = logger;
	this.serverPrefix = options.getPreferredHost() + ":" + options.getPort();
	compilerContext = compilerContextBuilder.build();
	}

	CompileDir recompile(Map<String, String> bindingProperties, AtomicReference<Progress> progress)
	throws UnableToCompleteException {
	if (options.shouldCompilePerFile()) {
	return compile(bindingProperties, progress, minimalRebuildCache);
	}
	return compile(bindingProperties, progress, new MinimalRebuildCache());
	}

	synchronized CompileDir compile(Map<String, String> bindingProperties,
	AtomicReference<Progress> progress) throws UnableToCompleteException {
	return compile(bindingProperties, progress, new MinimalRebuildCache());
	}

	private synchronized CompileDir compile(Map<String, String> bindingProperties,
	AtomicReference<Progress> progress, MinimalRebuildCache minimalRebuildCache)
	throws UnableToCompleteException {
	if (compilesDone == 0) {
	System.setProperty("java.awt.headless", "true");
	if (System.getProperty("gwt.speedtracerlog") == null) {
	System.setProperty("gwt.speedtracerlog",
	appSpace.getSpeedTracerLogFile().getAbsolutePath());
	}
	compilerContext = compilerContextBuilder.unitCache(
	UnitCacheSingleton.get(logger, appSpace.getUnitCacheDir())).build();
	}

	long startTime = System.currentTimeMillis();
	int compileId = ++compilesDone;
	CompileDir compileDir = makeCompileDir(compileId);
	TreeLogger compileLogger = makeCompileLogger(compileDir);

	boolean listenerFailed = false;
	try {
	options.getRecompileListener().startedCompile(originalModuleName, compileId, compileDir);
	} catch (Exception e) {
	compileLogger.log(TreeLogger.Type.WARN, "listener threw exception", e);
	listenerFailed = true;
	}

	boolean success = false;
	try {
	if (options.shouldCompileIncremental()) {
	// Just have one message for now.
	progress.set(new Progress.Compiling(moduleName.get(), compilesDone, 0, 1, "Compiling"));

	success = compileIncremental(compileLogger, compileDir);
	} else {
	success = compileMonolithic(compileLogger, bindingProperties, compileDir, progress,
	minimalRebuildCache);
	}
	} finally {
	try {
	options.getRecompileListener().finishedCompile(originalModuleName, compilesDone, success);
	} catch (Exception e) {
	compileLogger.log(TreeLogger.Type.WARN, "listener threw exception", e);
	listenerFailed = true;
	}
	}

	if (!success) {
	compileLogger.log(TreeLogger.Type.ERROR, "Compiler returned false");
	throw new UnableToCompleteException();
	}

	// keep the minimal rebuild cache for the next compile
	this.minimalRebuildCache = minimalRebuildCache;

	long elapsedTime = System.currentTimeMillis() - startTime;
	compileLogger.log(TreeLogger.Type.INFO,
	String.format("%.3fs total -- Compile completed", elapsedTime / 1000d));

	if (options.isCompileTest() && listenerFailed) {
	throw new UnableToCompleteException();
	}

	return publishedCompileDir;
	}

	synchronized CompileDir noCompile() throws UnableToCompleteException {
	long startTime = System.currentTimeMillis();
	CompileDir compileDir = makeCompileDir(++compilesDone);
	TreeLogger compileLogger = makeCompileLogger(compileDir);

	ModuleDef module = loadModule(compileLogger);
	String newModuleName = module.getName(); // includes any rename.
	moduleName.set(newModuleName);

	lastBuild.set(compileDir);

	try {
	// Prepare directory.
	File outputDir = new File(
	compileDir.getWarDir().getCanonicalPath() + "/" + getModuleName());
	if (!outputDir.exists()) {
	if (!outputDir.mkdir()) {
	compileLogger.log(TreeLogger.Type.WARN, "cannot create directory: " + outputDir);
	}
	}

	// Creates a "module_name.nocache.js" that just forces a recompile.
	String moduleScript = PageUtil.loadResource(Recompiler.class, "nomodule.nocache.js");
	moduleScript = moduleScript.replace("__MODULE_NAME__", getModuleName());
	PageUtil.writeFile(outputDir.getCanonicalPath() + "/" + getModuleName() + ".nocache.js",
	moduleScript);

	} catch (IOException e) {
	compileLogger.log(TreeLogger.Type.ERROR, "Error creating uncompiled module.", e);
	}
	long elapsedTime = System.currentTimeMillis() - startTime;
	compileLogger.log(TreeLogger.Type.INFO, "Module setup completed in " + elapsedTime + " ms");
	return compileDir;
	}

	private boolean compileIncremental(TreeLogger compileLogger, CompileDir compileDir) {
	BuildResultStatus buildResultStatus;
	// Perform a compile.
	if (incrementalBuilder == null) {
	// If it's the first compile.
	ResourceLoader resources = ResourceLoaders.forClassLoader(Thread.currentThread());
	resources = ResourceLoaders.forPathAndFallback(options.getSourcePath(), resources);
	this.resourceLoader.set(resources);

	incrementalBuilder = new IncrementalBuilder(originalModuleName,
	compileDir.getWarDir().getPath(), compileDir.getWorkDir().getPath(),
	compileDir.getGenDir().getPath(), resourceLoader.get());
	buildResultStatus = incrementalBuilder.build(compileLogger);
	} else {
	// If it's a rebuild.
	incrementalBuilder.setWarDir(compileDir.getWarDir().getPath());
	buildResultStatus = incrementalBuilder.rebuild(compileLogger);
	}

	if (incrementalBuilder.isRootModuleKnown()) {
	moduleName.set(incrementalBuilder.getRootModuleName());
	}
	// Unlike a monolithic compile, the incremental builder can successfully build but have no new
	// output (for example when no files have changed). So it's important to only publish the new
	// compileDir if it actually contains output.
	if (buildResultStatus.isSuccess() && buildResultStatus.outputChanged()) {
	publishedCompileDir = compileDir;
	}
	lastBuild.set(compileDir); // makes compile log available over HTTP

	return buildResultStatus.isSuccess();
	}

	private boolean compileMonolithic(TreeLogger compileLogger, Map<String, String> bindingProperties,
	CompileDir compileDir, AtomicReference<Progress> progress, MinimalRebuildCache rebuildCache)
	throws UnableToCompleteException {

	progress.set(new Progress.Compiling(moduleName.get(), compilesDone, 0, 2, "Loading modules"));

	CompilerOptions loadOptions = new CompilerOptionsImpl(compileDir, originalModuleName, options);
	compilerContext = compilerContextBuilder.options(loadOptions).build();

	ModuleDef module = loadModule(compileLogger);
	bindingProperties = restrictPermutations(logger, module, bindingProperties);

	// Propagates module rename.
	String newModuleName = module.getName();
	moduleName.set(newModuleName);

	// Check if we can skip the compile altogether.
	InputSummary input = new InputSummary(bindingProperties, module);
	if (input.equals(lastBuildInput)) {
	compileLogger.log(Type.INFO, "skipped compile because no input files have changed");
	return true;
	}

	progress.set(new Progress.Compiling(newModuleName, compilesDone, 1, 2, "Compiling"));
	// TODO: use speed tracer to get more compiler events?

	CompilerOptions runOptions = new CompilerOptionsImpl(compileDir, newModuleName, options);
	compilerContext = compilerContextBuilder.options(runOptions).build();

	boolean success = new Compiler(runOptions, rebuildCache).run(compileLogger, module);
	if (success) {
	publishedCompileDir = compileDir;
	lastBuildInput = input;
	} else {
	// always recompile after an error
	lastBuildInput = null;
	}
	lastBuild.set(compileDir); // makes compile log available over HTTP

	return success;
	}

	/**
	* Returns the log from the last compile. (It may be a failed build.)
	*/
	File getLastLog() {
	return lastBuild.get().getLogFile();
	}

	String getModuleName() {
	return moduleName.get();
	}

	ResourceLoader getResourceLoader() {
	return resourceLoader.get();
	}

	private TreeLogger makeCompileLogger(CompileDir compileDir)
	throws UnableToCompleteException {
	try {
	PrintWriterTreeLogger fileLogger =
	new PrintWriterTreeLogger(compileDir.getLogFile());
	fileLogger.setMaxDetail(options.getLogLevel());
	return new CompositeTreeLogger(logger, fileLogger);
	} catch (IOException e) {
	logger.log(TreeLogger.ERROR, "unable to open log file: " + compileDir.getLogFile(), e);
	throw new UnableToCompleteException();
	}
	}

	/**
	* Loads the module and configures it for SuperDevMode. (Does not restrict permutations.)
	*/
	private ModuleDef loadModule(TreeLogger logger) throws UnableToCompleteException {

	// make sure we get the latest version of any modified jar
	ZipFileClassPathEntry.clearCache();
	ResourceOracleImpl.clearCache();

	ResourceLoader resources = ResourceLoaders.forClassLoader(Thread.currentThread());
	resources = ResourceLoaders.forPathAndFallback(options.getSourcePath(), resources);
	this.resourceLoader.set(resources);

	// ModuleDefLoader.loadFromResources() checks for modified .gwt.xml files.
	ModuleDef moduleDef = ModuleDefLoader.loadFromResources(
	logger, compilerContext, originalModuleName, resources, true);
	compilerContext = compilerContextBuilder.module(moduleDef).build();

	// A snapshot of the module's configuration before we modified it.
	ConfigProps config = new ConfigProps(moduleDef);

	// We need a cross-site linker. Automatically replace the default linker.
	if (IFrameLinker.class.isAssignableFrom(moduleDef.getActivePrimaryLinker())) {
	moduleDef.addLinker("xsiframe");
	}

	// Check that we have a compatible linker.
	Class<? extends Linker> linker = moduleDef.getActivePrimaryLinker();
	if (!CrossSiteIframeLinker.class.isAssignableFrom(linker)) {
	logger.log(TreeLogger.ERROR,
	"linkers other than CrossSiteIFrameLinker aren't supported. Found: " + linker.getName());
	throw new UnableToCompleteException();
	}

	// Print a nice error if the superdevmode hook isn't present
	if (config.getStrings("devModeRedirectEnabled").isEmpty()) {
	throw new RuntimeException("devModeRedirectEnabled isn't set for module: " +
	moduleDef.getName());
	}

	// Disable the redirect hook here to make sure we don't have an infinite loop.
	// (There is another check in the JavaScript, but just in case.)
	overrideConfig(moduleDef, "devModeRedirectEnabled", "false");

	// Turn off "installCode" if it's on because it makes debugging harder.
	// (If it's already off, don't change anything.)
	if (config.getBoolean("installCode", true)) {
	overrideConfig(moduleDef, "installCode", "false");
	// Make sure installScriptJs is set to the default for compiling without installCode.
	overrideConfig(moduleDef, "installScriptJs",
	"com/google/gwt/core/ext/linker/impl/installScriptDirect.js");
	}

	// override computeScriptBase.js to enable the "Compile" button
	overrideConfig(moduleDef, "computeScriptBaseJs",
	"com/google/gwt/dev/codeserver/computeScriptBase.js");
	// Fix bug with SDM and Chrome 24+ where //@ sourceURL directives cause X-SourceMap header to be ignored
	// Frustratingly, Chrome won't canonicalize a relative URL
	overrideConfig(moduleDef, "includeSourceMapUrl", "http://" + serverPrefix +
	WebServer.sourceMapLocationForModule(moduleDef.getName()));

	// If present, set some config properties back to defaults.
	// (Needed for Google's server-side linker.)
	maybeOverrideConfig(moduleDef, "includeBootstrapInPrimaryFragment", "false");
	maybeOverrideConfig(moduleDef, "permutationsJs",
	"com/google/gwt/core/ext/linker/impl/permutations.js");
	maybeOverrideConfig(moduleDef, "propertiesJs",
	"com/google/gwt/core/ext/linker/impl/properties.js");

	overrideBinding(moduleDef, "compiler.useSourceMaps", "true");
	overrideBinding(moduleDef, "superdevmode", "on");
	return moduleDef;
	}

	/**
	* Restricts the compiled permutations by applying the given binding properties, if possible.
	* In some cases, a different binding may be chosen instead.
	* @return a map of the actual properties used.
	*/
	private Map<String, String> restrictPermutations(TreeLogger logger, ModuleDef moduleDef,
	Map<String, String> bindingProperties) {

	Map<String, String> chosenProps = Maps.newHashMap();

	for (Map.Entry<String, String> entry : bindingProperties.entrySet()) {
	String propName = entry.getKey();
	String propValue = entry.getValue();
	String actual = maybeSetBinding(logger, moduleDef, propName, propValue);
	if (actual != null) {
	chosenProps.put(propName, actual);
	}
	}

	return chosenProps;
	}

	/**
	* Attempts to set a binding property to the given value.
	* If the value is not allowed, see if we can find a value that will work.
	* There is a special case for "locale".
	* @return the value actually set, or null if unable to set the property
	*/
	private static String maybeSetBinding(TreeLogger logger, ModuleDef module, String propName,
	String newValue) {

	logger = logger.branch(TreeLogger.Type.INFO, "binding: " + propName + "=" + newValue);

	BindingProperty binding = module.getProperties().findBindingProp(propName);
	if (binding == null) {
	logger.log(TreeLogger.Type.WARN, "undefined property: '" + propName + "'");
	return null;
	}

	if (!binding.isAllowedValue(newValue)) {

	String[] allowedValues = binding.getAllowedValues(binding.getRootCondition());
	logger.log(TreeLogger.Type.WARN, "property '" + propName +
	"' cannot be set to '" + newValue + "'");
	logger.log(TreeLogger.Type.INFO, "allowed values: " +
	Joiner.on(", ").join(allowedValues));

	// See if we can fall back on a reasonable default.
	if (allowedValues.length == 1) {
	// There is only one possibility, so use it.
	newValue = allowedValues[0];
	} else if (binding.getName().equals("locale")) {
	// TODO: come up with a more general solution. Perhaps fail
	// the compile and give the user a way to override the property?
	newValue = chooseDefault(binding, "default", "en", "en_US");
	} else {
	// There is more than one. Continue and possibly compile multiple permutations.
	logger.log(TreeLogger.Type.INFO, "continuing without " + propName +
	". Sourcemaps may not work.");
	return null;
	}

	logger.log(TreeLogger.Type.INFO, "recovered with " + propName + "=" + newValue);
	}

	binding.setAllowedValues(binding.getRootCondition(), newValue);
	return newValue;
	}

	private static String chooseDefault(BindingProperty property, String... candidates) {
	for (String candidate : candidates) {
	if (property.isAllowedValue(candidate)) {
	return candidate;
	}
	}
	return property.getFirstLegalValue();
	}

	/**
	* Sets a binding even if it's set to a different value in the GWT application.
	*/
	private static void overrideBinding(ModuleDef module, String propName, String newValue) {
	BindingProperty binding = module.getProperties().findBindingProp(propName);
	if (binding != null) {
	binding.setAllowedValues(binding.getRootCondition(), newValue);
	}
	}

	private static boolean maybeOverrideConfig(ModuleDef module, String propName, String newValue) {
	ConfigurationProperty config = module.getProperties().findConfigProp(propName);
	if (config != null) {
	config.setValue(newValue);
	return true;
	}
	return false;
	}

	private static void overrideConfig(ModuleDef module, String propName, String newValue) {
	if (!maybeOverrideConfig(module, propName, newValue)) {
	throw new RuntimeException("not found: " + propName);
	}
	}

	private CompileDir makeCompileDir(int compileId)
	throws UnableToCompleteException {
	return CompileDir.create(appSpace.getCompileDir(compileId), logger);
	}

	/**
	* Summarizes the inputs to a GWT compile. (Immutable.)
	* Two summaries should be equal if the compiler's inputs are equal (with high probability).
	*/
	private static class InputSummary {
	private final ImmutableMap<String, String> bindingProperties;
	private final long moduleLastModified;
	private final long resourcesLastModified;
	private final long filenameHash;

	InputSummary(Map<String, String> bindingProperties, ModuleDef module) {
	this.bindingProperties = ImmutableMap.copyOf(bindingProperties);
	this.moduleLastModified = module.lastModified();
	this.resourcesLastModified = module.getResourceLastModified();
	this.filenameHash = module.getInputFilenameHash();
	}

	@Override
	public boolean equals(Object obj) {
	if (obj instanceof InputSummary) {
	InputSummary other = (InputSummary) obj;
	return bindingProperties.equals(other.bindingProperties) &&
	moduleLastModified == other.moduleLastModified &&
	resourcesLastModified == other.resourcesLastModified &&
	filenameHash == other.filenameHash;
	}
	return false;
	}

	@Override
	public int hashCode() {
	return Objects.hash(bindingProperties, moduleLastModified, resourcesLastModified,
	filenameHash);
	}
	}
	}