/// <summary>
/// Reads the metadata from a message file.
/// </summary>
/// <param name="msgID">The message ID.</param>
/// <param name="path">Fully qualified path to the message file.</param>
/// <returns>The <see cref="QueuedMsgInfo" />.</returns>
internal QueuedMsgInfo ReadMessageMetadata(Guid msgID, string path)
{
QueuedMsgInfo msgInfo;
int cbBody;
byte[] md5Hash;
long savePos;
using (var fsMsg = new EnhancedFileStream(path, FileMode.Open, FileAccess.ReadWrite))
{
try
{
// Read the message file header
if (fsMsg.ReadInt32() != MsgMagic) // Magic Number
{
throw new Exception();
}
if (fsMsg.ReadInt32() != 0) // Format Version
{
throw new Exception();
}
fsMsg.ReadInt32(); // Reserved
// Verify that the MD5 hash saved in then file matches the
// hash computed for the remainder of the file as it exists
// right now.
md5Hash = fsMsg.ReadBytes(MD5Hasher.DigestSize);
savePos = fsMsg.Position;
if (!Helper.ArrayEquals(md5Hash, MD5Hasher.Compute(fsMsg, fsMsg.Length - fsMsg.Position)))
{
throw new FormatException(string.Format("Message file [{0}] is corrupt. MD5 digests do not match.", path));
}
fsMsg.Position = savePos;
// Skip over the message body data
cbBody = fsMsg.ReadInt32();
fsMsg.Position = fsMsg.Position + cbBody;
// Read the metadata and add the provider specific information
msgInfo = new QueuedMsgInfo(fsMsg.ReadString16());
msgInfo.PersistID = msgInfo.ID;
msgInfo.ProviderData = path;
return(msgInfo);
}
catch
{
throw new FormatException(string.Format("Bad message file [{0}].", path));
}
}
}
/// <summary>
/// Loads the message index file. If the index does not exist or is corrupt then
/// the index will be rebuilt by performing a full scan of message files under
/// the root folder.
/// </summary>
/// <param name="newIndexFile">Pass as <c>true</c> if a new index file is being created.</param>
private void LoadIndex(bool newIndexFile)
{
string formatErr = string.Format("Invalid or missing index file [{0}].", indexPath);
int cMessages;
string[] files;
Dictionary <Guid, string> msgFiles;
TimedLock.AssertLocked(this);
messages = new Dictionary <Guid, QueuedMsgInfo>();
// List the message files and build a hash table mapping each message GUID
// the fully qualified path to the file.
files = Helper.GetFilesByPattern(root + "*.msg", SearchOption.AllDirectories);
msgFiles = new Dictionary <Guid, string>(files.Length);
foreach (string path in files)
{
string file = Path.GetFileName(path).ToLowerInvariant();
Guid msgID;
if (!file.EndsWith(".msg"))
{
continue;
}
try
{
msgID = new Guid(file.Substring(0, file.Length - 4));
}
catch
{
continue;
}
msgFiles[msgID] = path;
}
// Load the index file.
try
{
// Parse the index file header
fsIndex.Position = 0;
if (fsIndex.ReadInt32() != IndexMagic) // Magic Number
{
throw new FormatException(formatErr);
}
if (fsIndex.ReadInt32() != 0) // Format Version
{
throw new FormatException(formatErr);
}
fsIndex.ReadInt32(); // Reserved
if (fsIndex.ReadInt32() != 0)
{
throw new FormatException(string.Format("Index file [{0}] was not closed properly. Full message folder scan will be performed.", indexPath));
}
cMessages = fsIndex.ReadInt32(); // Message Count
// Parse the message metadata
for (int i = 0; i < cMessages; i++)
{
QueuedMsgInfo msgInfo;
msgInfo = new QueuedMsgInfo(fsIndex.ReadString16());
msgInfo.PersistID = msgInfo.ID;
msgInfo.ProviderData = root + fsIndex.ReadString16(); // Make the paths absolute
messages[msgInfo.ID] = msgInfo;
}
// Perform an extra consistency check by listing all of the message files
// under the root folder and comparing the message GUIDs encoded into the
// file names with the GUIDs loaded from the index file and then bringing
// the index into sync with the actual message files.
bool updated = false;
int cLoaded = 0;
// Delete any metadata for messages that exist in the index
// but don't exist on the file system.
var delList = new List <Guid>();
foreach (Guid msgID in messages.Keys)
{
if (!msgFiles.ContainsKey(msgID))
{
delList.Add(msgID);
}
}
foreach (Guid msgID in delList)
{
messages.Remove(msgID);
}
if (delList.Count > 0)
{
updated = true;
SysLog.LogWarning(string.Format("Message index [{0}] has message metadata for messages that do not exist. [{1}] messages will be removed from the index.", indexPath, delList.Count));
}
// Load metadata for messages that exist in the file system
// but were not in the index.
foreach (Guid msgID in msgFiles.Keys)
{
if (!messages.ContainsKey(msgID))
{
string path = msgFiles[msgID];
try
{
messages[msgID] = ReadMessageMetadata(msgID, path);
cLoaded++;
}
catch (Exception e)
{
SysLog.LogException(e);
}
}
}
if (cLoaded > 0)
{
updated = true;
SysLog.LogWarning(string.Format("Message index [{0}] is missing metadata for [{1}] messages. Missing entries will be added.", indexPath, cLoaded));
}
if (updated)
{
SaveIndex(true);
}
// Mark the index as "open" for crash detection.
fsIndex.Position = OpenFlagOffset;
fsIndex.WriteInt32(1);
fsIndex.Flush();
}
catch
{
if (newIndexFile)
{
SysLog.LogWarning("Rebuilding missing message index file [{0}].", indexPath);
}
else
{
SysLog.LogWarning("Rebuilding corrupt message index file [{0}].", indexPath);
}
// Clear the index file if there was a serious error and then
// rebuild it from scratch by scanning the message metadata.
fsIndex.SetLength(0);
fsIndex.Flush();
messages.Clear();
foreach (Guid msgID in msgFiles.Keys)
{
try
{
messages.Add(msgID, ReadMessageMetadata(msgID, msgFiles[msgID]));
}
catch (Exception e2)
{
SysLog.LogException(e2);
}
}
// Save the index, marking the file as "open" for crash detection
SaveIndex(true);
}
}
/// <summary>
/// Loads the cache index file.
/// </summary>
private void LoadIndex()
{
var indexPath = Path.Combine(settings.PhraseCacheFolder, IndexFileName);
try
{
if (!File.Exists(indexPath))
{
// No index exists yet, so create an empty one.
SaveIndex(false);
return;
}
using (var fs = new EnhancedFileStream(indexPath, FileMode.Open))
{
int count;
if (fs.ReadInt32() != Magic)
{
throw new SwitchException("[PhraseCache] cannot read index file [{0}] due to an invalid magic number. The existing cache will be purged.", indexPath);
}
count = fs.ReadInt32();
for (int i = 0; i < count; i++)
{
string text;
string voice;
string actualVoice;
PhraseType phraseType;
TtsEncoding encoding;
TtsSampleRate rate;
DateTime lastAccessUtc;
string path;
Phrase phrase;
phraseType = (PhraseType)Enum.Parse(typeof(PhraseType), fs.ReadString16());
text = fs.ReadString32();
voice = fs.ReadString16();
actualVoice = fs.ReadString16();
encoding = (TtsEncoding)Enum.Parse(typeof(TtsEncoding), fs.ReadString16());
rate = (TtsSampleRate)Enum.Parse(typeof(TtsSampleRate), fs.ReadString16());
lastAccessUtc = new DateTime(fs.ReadInt64());
path = fs.ReadString16();
phrase = new Phrase(phraseType, voice, encoding, rate, text)
{
Path = path,
ActualVoice = actualVoice,
LastAccessUtc = lastAccessUtc,
};
index[GetCacheKey(phrase)] = phrase;
}
}
}
catch (Exception e)
{
// We're going to handle all exceptions leaving the loaded phrase
// table empty. This will have the effect of starting the cache
// from scratch. Eventually, all of the existing files will be
// purged and the presumably bad index file will be overwritten.
index.Clear();
SysLog.LogException(e);
}
}