public Library(WebLibraryDetail web_library_detail)
{
this.web_library_detail = web_library_detail;
Logging.Info("Library basepath is at {0}", LIBRARY_BASE_PATH);
Logging.Info("Library document basepath is at {0}", LIBRARY_DOCUMENTS_BASE_PATH);
Directory.CreateDirectory(LIBRARY_BASE_PATH);
Directory.CreateDirectory(LIBRARY_DOCUMENTS_BASE_PATH);
library_db = new LibraryDB(LIBRARY_BASE_PATH);
folder_watcher_manager = new FolderWatcherManager(this);
library_index = new LibraryIndex(this);
ai_tag_manager = new AITagManager(this);
recently_read_manager = new RecentlyReadManager(this);
blackwhite_list_manager = new BlackWhiteListManager(this);
password_manager = new PasswordManager(this);
expedition_manager = new ExpeditionManager(this);
// Start loading the documents in the background...
SafeThreadPool.QueueUserWorkItem(o => BuildFromDocumentRepository());
}
public List <LibraryItem> GetLibraryItems(string extension, List <string> fingerprints = null, int MaxRecordCount = 0)
{
List <LibraryItem> results = new List <LibraryItem>();
List <Exception> database_corruption = new List <Exception>();
try
{
lock (DBAccessLock.db_access_lock)
{
using (var connection = GetConnection())
{
connection.Open();
string command_string = "SELECT fingerprint, extension, md5, data FROM LibraryItem WHERE 1=1 ";
command_string += turnArgumentSetIntoQueryPart("fingerprint", fingerprints);
command_string += turnArgumentIntoQueryPart("extension", extension);
if (MaxRecordCount > 0)
{
// http://www.sqlitetutorial.net/sqlite-limit/
command_string += " LIMIT @maxnum";
}
using (var command = new SQLiteCommand(command_string, connection))
{
//turnArgumentIntoQueryParameter(command, "fingerprint", fingerprint);
turnArgumentIntoQueryParameter(command, "extension", extension);
if (MaxRecordCount > 0)
{
command.Parameters.AddWithValue("@maxnum", MaxRecordCount);
}
using (SQLiteDataReader reader = command.ExecuteReader())
{
while (reader.Read())
{
LibraryItem result = new LibraryItem();
int field_count = 0;
// Read the record in 2-3 gangs, as there's some DBs out there which have the BLOB as NOT A BLOB but as a STRING type instead:
// this is probably caused by manual editing (using SQLite CLI or other means) of the BLOB record.
// gang 1: load the field count and header fields: these almost never fail.
try
{
field_count = reader.FieldCount;
result.fingerprint = reader.GetString(0);
result.extension = reader.GetString(1);
result.md5 = reader.GetString(2);
}
catch (Exception ex)
{
string msg = String.Format("LibraryDB::GetLibraryItems: Database record #{4} gang 1 decode failure for DB '{0}': fingerprint={1}, ext={2}, md5={3}, field_count={5}.",
library_path,
String.IsNullOrEmpty(result.fingerprint) ? "???" : result.fingerprint,
String.IsNullOrEmpty(result.extension) ? "???" : result.extension,
String.IsNullOrEmpty(result.md5) ? "???" : result.md5,
reader.StepCount, // ~= results.Count + database_corruption.Count
field_count
);
Logging.Error(ex, "{0}", msg);
Exception ex2 = new Exception(msg, ex);
database_corruption.Add(ex2);
// it's no use to try to decode the rest of the DB record: it is lost to us
continue;
}
if (true)
{
Exception ex2 = null;
long total_bytes = 0;
// gang 2: get the BLOB
try
{
total_bytes = reader.GetBytes(3, 0, null, 0, 0);
result.data = new byte[total_bytes];
long total_bytes2 = reader.GetBytes(3, 0, result.data, 0, (int)total_bytes);
if (total_bytes != total_bytes2)
{
throw new Exception("Error reading blob - blob size different on each occasion.");
}
results.Add(result);
continue;
}
catch (Exception ex)
{
string msg = String.Format("LibraryDB::GetLibraryItems: Database record #{4} BLOB decode failure for DB '{0}': fingerprint={1}, ext={2}, md5={3}, BLOB length={5}.",
library_path,
String.IsNullOrEmpty(result.fingerprint) ? "???" : result.fingerprint,
String.IsNullOrEmpty(result.extension) ? "???" : result.extension,
String.IsNullOrEmpty(result.md5) ? "???" : result.md5,
reader.StepCount, // ~= results.Count + database_corruption.Count
total_bytes
);
ex2 = new Exception(msg, ex);
// gang 3: get at the BLOB-née-STRING in an indirect way
object[] fields = new object[5];
try
{
reader.GetValues(fields);
byte[] arr = fields[3] as byte[];
if (arr != null)
{
string blob = Encoding.UTF8.GetString(arr, 0, arr.Length);
result.data = new byte[arr.Length];
Array.Copy(arr, result.data, arr.Length);
results.Add(result);
Logging.Warn("LibraryDB::GetLibraryItems: Database record #{0} BLOB field is instead decoded as UTF8 STRING, following this RESOLVED ERROR: {1}\n Decoded STRING content:\n{2}",
reader.StepCount, // ~= results.Count + database_corruption.Count
ex2.ToStringAllExceptionDetails(),
blob);
continue;
}
else
{
throw new Exception("Cannot extract BLOB field.");
}
}
catch (Exception ex3)
{
Logging.Error(ex2);
Logging.Error(ex3);
database_corruption.Add(ex2);
}
}
}
}
reader.Close();
}
}
connection.Close();
}
//
// see SO link above at the `DBAccessLock.db_access_lock` declaration.
//
// We keep this *inside* the critical section so that we know we'll be the only active SQLite
// action which just transpired.
// *This* is also the reason why I went with a *global* lock (singleton) for *all* databases,
// even while *theoretically* this is *wrong* or rather: *unnecessary* as the databases
// i.e. Qiqqa Libraries shouldn't bite one another. I, however, need to ensure that the
// added `System.Data.SQLite.SQLiteConnection.ClearAllPools();` statements don't foul up
// matters in library B while lib A I/O is getting cleaned up.
//
// In short: Yuck. + Cave canem.
//
SQLiteConnection.ClearAllPools();
}
}
catch (Exception ex)
{
Logging.Error(ex, "LibraryDB::GetLibraryItems: Database I/O failure for DB '{0}'.", library_path);
LibraryDB.FurtherDiagnoseDBProblem(ex, database_corruption, library_path);
throw;
}
if (database_corruption.Count > 0)
{
// report database corruption: the user may want to recover from this ASAP!
if (MessageBoxes.AskErrorQuestion(true, "Library '{0}' has some data corruption. Do you want to abort the application to attempt recovery using external tools, e.g. a data restore from backup?\n\nWhen you answer NO, we will continue with what we could recover so far instead.\n\n\nConsult the Qiqqa logfiles to see the individual corruptions reported.",
library_path))
{
Logging.Warn("User chose to abort the application on database corruption report");
Environment.Exit(3);
}
}
return(results);
}
public void PutBlob(string fingerprint, string extension, byte[] data)
{
// Guard
if (String.IsNullOrWhiteSpace(fingerprint))
{
throw new Exception("Can't store in LibraryDB with null fingerprint.");
}
if (String.IsNullOrWhiteSpace(extension))
{
throw new Exception("Can't store in LibraryDB with null extension.");
}
// Calculate the MD5 of this blobbiiiieeeeee
string md5 = StreamMD5.FromBytes(data);
try
{
lock (DBAccessLock.db_access_lock)
{
using (var connection = GetConnection())
{
connection.Open();
using (var transaction = connection.BeginTransaction())
{
bool managed_update = false;
using (var command = new SQLiteCommand("UPDATE LibraryItem SET MD5=@md5, DATA=@data WHERE fingerprint=@fingerprint AND extension=@extension", connection, transaction))
{
command.Parameters.AddWithValue("@md5", md5);
command.Parameters.AddWithValue("@data", data);
command.Parameters.AddWithValue("@fingerprint", fingerprint);
command.Parameters.AddWithValue("@extension", extension);
int num_rows_updated = command.ExecuteNonQuery();
if (1 == num_rows_updated)
{
managed_update = true;
}
}
if (!managed_update)
{
using (var command = new SQLiteCommand("INSERT INTO LibraryItem(fingerprint, extension, md5, data) VALUES(@fingerprint, @extension, @md5, @data)", connection, transaction))
{
command.Parameters.AddWithValue("@fingerprint", fingerprint);
command.Parameters.AddWithValue("@extension", extension);
command.Parameters.AddWithValue("@md5", md5);
command.Parameters.AddWithValue("@data", data);
command.ExecuteNonQuery();
}
}
transaction.Commit();
}
connection.Close();
}
//
// see SO link above at the `DBAccessLock.db_access_lock` declaration.
//
// We keep this *inside* the critical section so that we know we'll be the only active SQLite
// action which just transpired.
// *This* is also the reason why I went with a *global* lock (singleton) for *all* databases,
// even while *theoretically* this is *wrong* or rather: *unnecessary* as the databases
// i.e. Qiqqa Libraries shouldn't bite one another. I, however, need to ensure that the
// added `System.Data.SQLite.SQLiteConnection.ClearAllPools();` statements don't foul up
// matters in library B while lib A I/O is getting cleaned up.
//
// In short: Yuck. + Cave canem.
//
SQLiteConnection.ClearAllPools();
}
}
catch (Exception ex)
{
Logging.Error(ex, "LibraryDB::PutBLOB: Database I/O failure for DB '{0}'.", library_path);
LibraryDB.FurtherDiagnoseDBProblem(ex, null, library_path);
throw;
}
}
protected virtual void Dispose(bool disposing)
{
Logging.Debug("Library::Dispose({0}) @{1}", disposing, dispose_count);
try
{
LibraryIsKilled = true;
if (dispose_count == 0)
{
// Get rid of managed resources / get rid of cyclic references:
// Do we need to check that the library has finished being loaded?
// Switch off the living things
library_index?.Dispose();
folder_watcher_manager?.Dispose();
// NULL the memory database
Utilities.LockPerfTimer l2_clk = Utilities.LockPerfChecker.Start();
lock (pdf_documents_lock)
{
l2_clk.LockPerfTimerStop();
pdf_documents.Clear();
pdf_documents = null;
}
}
// Clear the references for sanity's sake
expedition_manager = null;
password_manager = null;
blackwhite_list_manager = null;
recently_read_manager = null;
ai_tag_manager = null;
library_index = null;
folder_watcher_manager = null;
library_db = null;
#if false
web_library_detail = null; // cyclic reference as WebLibraryDetail instance reference us, so we MUST nil this one to break the cycle for the GC to work well.
#else
// cyclic reference as WebLibraryDetail instance reference us, so we MUST nil this one to break the cycle for the GC to work well.
//
// WARNING:
// The most obvious way (see above in `#if false` branch) would be to NULL the weblibdetail reference, but this will cause all sorts of extremely
// nasty crashes, including memory corruption, as this reference is accessed in Library background task(s) which might discover that the
// library at hand has been killed rather late.
//
// When those code chunks, e.g. *anything* inside `BuildFromDocumentRepository()`, crash on a NULL dereference of any of the other NULLed
// library members, the error resolution code highly depends on a *still working* web_library_detail reference/instance.
// To resolve the cyclic reference in there (as the web_lib_detail has a `Library` reference), we hack this by creating a *temporary*
// intermediate web_library_detail instance, which is a copy of the original *sans Library reference*.
// We DO NOT nuke the Library member in the original web_library_detail as that would cause all sorts of other harm since there's other
// code which depends on a certain valid lifetime of that instance and that code should dispose of the record once it is done using it...
//
// Cloning...
web_library_detail = web_library_detail.CloneSansLibraryReference();
#endif
}
catch (Exception ex)
{
Logging.Error(ex);
}
++dispose_count;
}
