/// <summary>
/// Grab the path to the file, for use in our location information.
/// </summary>
public override void Load(string fullPath)
{
DetermineWhetherToLoadReadOnly(fullPath);
_fullPath = fullPath;
using (var xtr = XmlReaderExtension.Create(fullPath, _loadAsReadOnly ?? false))
{
this.Load(xtr.Reader);
}
}
private bool IsInvalidEntry(string projectFile, ProjectRootElement projectRootElement)
{
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)
{
if (fileInfo.LastWriteTime != projectRootElement.LastWriteTimeWhenRead)
{
// File was changed on disk by external means. Cached version is no longer valid.
// 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.
return(true);
}
else if (s_сheckFileContent)
{
// 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)
{
return(true);
}
}
}
}
return(false);
}
/// <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 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)
{
var 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);
}
}
