/// <summary>
/// Performs path manipulations on the given item-spec as directed.
///
/// Supported modifiers:
/// %(FullPath) = full path of item
/// %(RootDir) = root directory of item
/// %(Filename) = item filename without extension
/// %(Extension) = item filename extension
/// %(RelativeDir) = item directory as given in item-spec
/// %(Directory) = full path of item directory relative to root
/// %(RecursiveDir) = portion of item path that matched a recursive wildcard
/// %(Identity) = item-spec as given
/// %(ModifiedTime) = last write time of item
/// %(CreatedTime) = creation time of item
/// %(AccessedTime) = last access time of item
///
/// NOTES:
/// 1) This method always returns an empty string for the %(RecursiveDir) modifier because it does not have enough
/// information to compute it -- only the BuildItem class can compute this modifier.
/// 2) The %(ModifiedTime), %(CreatedTime) and %(AccessedTime) modifiers are never cached because they are not constants.
/// </summary>
/// <remarks>
/// Methods of the Path class "normalize" slashes and periods. For example:
/// 1) successive slashes are combined into 1 slash
/// 2) trailing periods are discarded
/// 3) forward slashes are changed to back-slashes
///
/// As a result, we cannot rely on any file-spec that has passed through a Path method to remain the same. We will
/// therefore not bother preserving slashes and periods when file-specs are transformed.
/// </remarks>
/// <owner>SumedhK</owner>
/// <param name="currentDirectory">The root directory for relative item-specs. When called on the Engine thread, this is the project directory. When called as part of building a task, it is null, indicating that the current directory should be used.</param>
/// <param name="itemSpec">The item-spec to modify.</param>
/// <param name="modifier">The modifier to apply to the item-spec.</param>
/// <param name="cachedModifiers">Cache of previously computed modifiers (if null, this method will create it unless the modifier cannot be cached).</param>
/// <returns>The modified item-spec (can be empty string, but will never be null).</returns>
/// <exception cref="InvalidOperationException">Thrown when the item-spec is not a path.</exception>
internal static string GetItemSpecModifier(string currentDirectory, string itemSpec, string modifier, ref Hashtable cachedModifiers)
{
ErrorUtilities.VerifyThrow(itemSpec != null, "Need item-spec to modify.");
ErrorUtilities.VerifyThrow(modifier != null, "Need modifier to apply to item-spec.");
string modifiedItemSpec = null;
// check if we have computed this modifier before
if (cachedModifiers != null)
{
ErrorUtilities.VerifyThrow((string)cachedModifiers[String.Empty] == itemSpec,
"The cache of modifiers is only valid for one item-spec. If the item-spec changes, the cache must be nulled out, or a different cache passed in.");
modifiedItemSpec = (string)cachedModifiers[modifier];
}
if (modifiedItemSpec == null)
{
// certain properties can't be cached -- this will be turned to true in those cases
bool isVolatile = false;
try
{
if (String.Compare(modifier, ItemSpecModifiers.FullPath, StringComparison.OrdinalIgnoreCase) == 0)
{
if (currentDirectory == null)
{
currentDirectory = String.Empty;
}
modifiedItemSpec = GetFullPath(itemSpec, currentDirectory);
}
else if (String.Compare(modifier, ItemSpecModifiers.RootDir, StringComparison.OrdinalIgnoreCase) == 0)
{
if (currentDirectory == null)
{
currentDirectory = String.Empty;
}
string fullPath = Path.GetFullPath(Path.Combine(currentDirectory, itemSpec));
modifiedItemSpec = Path.GetPathRoot(fullPath);
if (!EndsWithSlash(modifiedItemSpec))
{
Debug.Assert(FileUtilitiesRegex.UNCPattern.IsMatch(modifiedItemSpec),
"Only UNC shares should be missing trailing slashes.");
// restore/append trailing slash if Path.GetPathRoot() has either removed it, or failed to add it
// (this happens with UNC shares)
modifiedItemSpec += Path.DirectorySeparatorChar;
}
}
else if (String.Compare(modifier, ItemSpecModifiers.Filename, StringComparison.OrdinalIgnoreCase) == 0)
{
// if the item-spec is a root directory, it can have no filename
if (Path.GetDirectoryName(itemSpec) == null)
{
// NOTE: this is to prevent Path.GetFileNameWithoutExtension() from treating server and share elements
// in a UNC file-spec as filenames e.g. \\server, \\server\share
modifiedItemSpec = String.Empty;
}
else
{
modifiedItemSpec = Path.GetFileNameWithoutExtension(itemSpec);
}
}
else if (String.Compare(modifier, ItemSpecModifiers.Extension, StringComparison.OrdinalIgnoreCase) == 0)
{
// if the item-spec is a root directory, it can have no extension
if (Path.GetDirectoryName(itemSpec) == null)
{
// NOTE: this is to prevent Path.GetExtension() from treating server and share elements in a UNC
// file-spec as filenames e.g. \\server.ext, \\server\share.ext
modifiedItemSpec = String.Empty;
}
else
{
modifiedItemSpec = Path.GetExtension(itemSpec);
}
}
else if (String.Compare(modifier, ItemSpecModifiers.RelativeDir, StringComparison.OrdinalIgnoreCase) == 0)
{
modifiedItemSpec = GetDirectory(itemSpec);
}
else if (String.Compare(modifier, ItemSpecModifiers.Directory, StringComparison.OrdinalIgnoreCase) == 0)
{
if (currentDirectory == null)
{
currentDirectory = String.Empty;
}
modifiedItemSpec = GetDirectory(GetFullPath(itemSpec, currentDirectory));
Match root = FileUtilitiesRegex.DrivePattern.Match(modifiedItemSpec);
if (!root.Success)
{
root = FileUtilitiesRegex.UNCPattern.Match(modifiedItemSpec);
}
if (root.Success)
{
ErrorUtilities.VerifyThrow((modifiedItemSpec.Length > root.Length) && IsSlash(modifiedItemSpec[root.Length]),
"Root directory must have a trailing slash.");
modifiedItemSpec = modifiedItemSpec.Substring(root.Length + 1);
}
}
else if (String.Compare(modifier, ItemSpecModifiers.RecursiveDir, StringComparison.OrdinalIgnoreCase) == 0)
{
// only the BuildItem class can compute this modifier -- so leave empty
modifiedItemSpec = String.Empty;
}
else if (String.Compare(modifier, ItemSpecModifiers.Identity, StringComparison.OrdinalIgnoreCase) == 0)
{
modifiedItemSpec = itemSpec;
}
else if (String.Compare(modifier, ItemSpecModifiers.ModifiedTime, StringComparison.OrdinalIgnoreCase) == 0)
{
isVolatile = true;
// About to go out to the filesystem. This means data is leaving the engine, so need
// to unescape first.
string unescapedItemSpec = EscapingUtilities.UnescapeAll(itemSpec);
FileInfo info = FileUtilities.GetFileInfoNoThrow(unescapedItemSpec);
if (info != null)
{
modifiedItemSpec = info.LastWriteTime.ToString(FileTimeFormat, null);
}
else
{
// File does not exist, or path is a directory
modifiedItemSpec = String.Empty;
}
}
else if (String.Compare(modifier, ItemSpecModifiers.CreatedTime, StringComparison.OrdinalIgnoreCase) == 0)
{
isVolatile = true;
// About to go out to the filesystem. This means data is leaving the engine, so need
// to unescape first.
string unescapedItemSpec = EscapingUtilities.UnescapeAll(itemSpec);
if (File.Exists(unescapedItemSpec))
{
modifiedItemSpec = File.GetCreationTime(unescapedItemSpec).ToString(FileTimeFormat, null);
}
else
{
// File does not exist, or path is a directory
modifiedItemSpec = String.Empty;
}
}
else if (String.Compare(modifier, ItemSpecModifiers.AccessedTime, StringComparison.OrdinalIgnoreCase) == 0)
{
isVolatile = true;
// About to go out to the filesystem. This means data is leaving the engine, so need
// to unescape first.
string unescapedItemSpec = EscapingUtilities.UnescapeAll(itemSpec);
if (File.Exists(unescapedItemSpec))
{
modifiedItemSpec = File.GetLastAccessTime(unescapedItemSpec).ToString(FileTimeFormat, null);
}
else
{
// File does not exist, or path is a directory
modifiedItemSpec = String.Empty;
}
}
else
{
ErrorUtilities.VerifyThrow(false, "\"{0}\" is not a valid item-spec modifier.", modifier);
}
}
catch (Exception e) // Catching Exception, but rethrowing unless it's a well-known exception.
{
if (ExceptionHandling.NotExpectedException(e))
{
throw;
}
ErrorUtilities.VerifyThrowInvalidOperation(false, "Shared.InvalidFilespecForTransform", modifier, itemSpec, e.Message);
}
ErrorUtilities.VerifyThrow(modifiedItemSpec != null, "The item-spec modifier \"{0}\" was not evaluated.", modifier);
// cache the modifier
if (!isVolatile)
{
if (cachedModifiers == null)
{
cachedModifiers = new Hashtable(StringComparer.OrdinalIgnoreCase);
// mark the cache to indicate the item-spec for which it was created
// NOTE: we've intentionally picked a key here that will never conflict with any modifier name -- if we
// use the item-spec as the key, it's possible for it to conflict with the name of a modifier
cachedModifiers[String.Empty] = itemSpec;
}
cachedModifiers[modifier] = modifiedItemSpec;
}
}
return(modifiedItemSpec);
}
