/// <summary> /// Add or rename an entry in the cache. /// Old full path may be null iff it was not already in the cache. /// </summary> /// <remarks> /// Must be called within the cache lock. /// </remarks> private void RenameEntryInternal(string oldFullPathIfAny, ProjectRootElement projectRootElement) { ErrorUtilities.VerifyThrowInternalNull(projectRootElement.FullPath, "FullPath"); if (oldFullPathIfAny != null) { ErrorUtilities.VerifyThrowInternalRooted(oldFullPathIfAny); ErrorUtilities.VerifyThrow(_weakCache[oldFullPathIfAny] == projectRootElement, "Should already be present"); _weakCache.Remove(oldFullPathIfAny); } // There may already be a ProjectRootElement in the cache with the new name. In this case we cannot throw an exception; // we must merely replace it. This is because it may be an unrooted entry // (and thus gone from the client's point of view) that merely remains // in the cache because we still have a reference to it from our strong cache. // Another possibility is that there are two, unrelated, un-saved, in-memory projects that were given the same path. // Replacing the cache entry does not in itself cause a problem -- if there are any actual users of the old // entry they will not be affected. There would then exist more than one ProjectRootElement with the same path, // but clients ought not get themselves into such a state - and unless they save them to disk, // it may not be a problem. Replacing also doesn't cause a problem for the strong cache, // as it is never consulted by us, but it is reasonable for us to remove the old entry in that case. ProjectRootElement existingWeakEntry; _weakCache.TryGetValue(projectRootElement.FullPath, out existingWeakEntry); if (existingWeakEntry != null && !Object.ReferenceEquals(existingWeakEntry, projectRootElement)) { _strongCache.Remove(existingWeakEntry); RaiseProjectRootElementRemovedFromStrongCache(existingWeakEntry); } DebugTraceCache("Adding: ", projectRootElement.FullPath); _weakCache[projectRootElement.FullPath] = projectRootElement; BoostEntryInStrongCache(projectRootElement); }
/// <summary> /// Returns an existing ProjectRootElement for the specified file path, if any. /// If none exists, calls the provided delegate to load one, and adds that to the cache. /// The reason that it calls back to do this is so that the cache is locked between determining /// that the entry does not exist and adding the entry. /// /// If <see cref="_autoReloadFromDisk"/> was set to true, and the file on disk has changed since it was cached, /// it will be reloaded before being returned. /// /// Thread safe. /// </summary> /// <remarks> /// Never needs to consult the strong cache as well, since if the item is in there, it will /// not have left the weak cache. /// If item is found, boosts it to the top of the strong cache. /// </remarks> /// <param name="projectFile">The project file which contains the ProjectRootElement. Must be a full path.</param> /// <param name="openProjectRootElement">The delegate to use to load if necessary. May be null.</param> /// <param name="isExplicitlyLoaded"><code>true</code> if the project is explicitly loaded, otherwise <code>false</code>.</param> /// <param name="preserveFormatting"><code>true</code> to the project was loaded with the formated preserved, otherwise <code>false</code>.</param> /// <returns>The ProjectRootElement instance if one exists. Null otherwise.</returns> internal override ProjectRootElement Get(string projectFile, OpenProjectRootElement openProjectRootElement, bool isExplicitlyLoaded, bool?preserveFormatting) { // Should already have been canonicalized ErrorUtilities.VerifyThrowInternalRooted(projectFile); lock (_locker) { ProjectRootElement projectRootElement; _weakCache.TryGetValue(projectFile, out projectRootElement); if (preserveFormatting != null && projectRootElement != null && projectRootElement.XmlDocument.PreserveWhitespace != preserveFormatting) { // Cached project doesn't match preserveFormatting setting, so reload it projectRootElement.Reload(true, preserveFormatting); } if (projectRootElement != null && _autoReloadFromDisk) { FileInfo fileInfo = FileUtilities.GetFileInfoNoThrow(projectFile); // If the file doesn't exist on disk, go ahead and use the cached version. // It's an in-memory project that hasn't been saved yet. if (fileInfo != null) { bool forgetEntry = false; if (fileInfo.LastWriteTime != projectRootElement.LastWriteTimeWhenRead) { // File was changed on disk by external means. Cached version is no longer reliable. // We could throw here or ignore the problem, but it is a common and reasonable pattern to change a file // externally and load a new project over it to see the new content. So we dump it from the cache // to force a load from disk. There might then exist more than one ProjectRootElement with the same path, // but clients ought not get themselves into such a state - and unless they save them to disk, // it may not be a problem. forgetEntry = true; } else if (!String.IsNullOrEmpty(Environment.GetEnvironmentVariable("MSBUILDCACHECHECKFILECONTENT"))) { // QA tests run too fast for the timestamp check to work. This environment variable is for their // use: it checks the file content as well as the timestamp. That's better than completely disabling // the cache as we get test coverage of the rest of the cache code. XmlDocument document = new XmlDocument(); document.PreserveWhitespace = projectRootElement.XmlDocument.PreserveWhitespace; using (var xtr = XmlReaderExtension.Create(projectRootElement.FullPath, projectRootElement.ProjectRootElementCache.LoadProjectsReadOnly)) { document.Load(xtr.Reader); } string diskContent = document.OuterXml; string cacheContent = projectRootElement.XmlDocument.OuterXml; if (diskContent != cacheContent) { forgetEntry = true; } } if (forgetEntry) { ForgetEntry(projectRootElement); DebugTraceCache("Out of date dropped from XML cache: ", projectFile); projectRootElement = null; } } } if (projectRootElement == null && openProjectRootElement != null) { projectRootElement = openProjectRootElement(projectFile, this); ErrorUtilities.VerifyThrowInternalNull(projectRootElement, "projectRootElement"); ErrorUtilities.VerifyThrow(projectRootElement.FullPath == projectFile, "Got project back with incorrect path"); ErrorUtilities.VerifyThrow(_weakCache.Contains(projectFile), "Open should have renamed into cache and boosted"); } else if (projectRootElement != null) { DebugTraceCache("Satisfied from XML cache: ", projectFile); BoostEntryInStrongCache(projectRootElement); } // An implicit load will never reset the explicit flag. if (projectRootElement != null && isExplicitlyLoaded) { projectRootElement.MarkAsExplicitlyLoaded(); } return(projectRootElement); } }