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/* engine.vala
*
* Copyright © 2011 Collabora Ltd.
* By Siegfried-Angel Gevatter Pujals <siegfried@gevatter.com>
* By Seif Lotfy <seif@lotfy.com>
*
* Based upon a Python implementation (2009-2011) by:
* Markus Korn <thekorn@gmx.net>
* Mikkel Kamstrup Erlandsen <mikkel.kamstrup@gmail.com>
* Seif Lotfy <seif@lotfy.com>
* Siegfried-Angel Gevatter Pujals <siegfried@gevatter.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 2.1 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
using Zeitgeist;
using Zeitgeist.SQLite;
using Zeitgeist.Utils;
namespace Zeitgeist
{
public class Engine : DbReader
{
public ExtensionStore extension_store;
private ExtensionCollection extension_collection;
private uint32 last_id;
public Engine () throws EngineError
{
Object (database: new Zeitgeist.SQLite.Database ());
// TODO: take care of this if we decide to subclass Engine
// (we need to propagate the error, so it can't go to construct {})
last_id = database.get_last_id ();
extension_collection = new ExtensionCollection (this);
}
construct
{
extension_store = new ExtensionStore (this);
}
public string[] get_extension_names ()
{
return extension_collection.get_extension_names ();
}
public uint32[] insert_events (GenericArray<Event> events,
BusName? sender=null) throws EngineError
{
// Any changes to events need to be done here so they'll
// be taken into consideration by the extensions (LP: #928804).
for (int i = 0; i < events.length; ++i)
{
preprocess_event (events[i]);
}
extension_collection.call_pre_insert_events (events, sender);
uint32[] event_ids = new uint32[events.length];
EngineError? err = null;
database.begin_transaction ();
try
{
for (int i = 0; i < events.length; ++i)
{
if (events[i] != null)
event_ids[i] = insert_event (events[i]);
}
database.end_transaction ();
}
catch (EngineError e)
{
err = e;
database.abort_transaction ();
}
if (err != null) throw err;
extension_collection.call_post_insert_events (events, sender);
return event_ids;
}
private void preprocess_event (Event event) throws EngineError
{
// Iterate through subjects and check for validity
for (int i = 0; i < event.num_subjects(); ++i)
{
unowned Subject subject = event.subjects[i];
// If current_uri is unset, give it the same value as URI
if (is_empty_string (subject.current_uri))
subject.current_uri = subject.uri;
if (event.interpretation == ZG.MOVE_EVENT
&& subject.uri == subject.current_uri)
{
throw new EngineError.INVALID_ARGUMENT (
"Redundant event: event.interpretation indicates " +
"the uri has been moved yet the subject.uri and " +
"subject.current_uri are identical");
}
else if (event.interpretation != ZG.MOVE_EVENT
&& subject.uri != subject.current_uri)
{
throw new EngineError.INVALID_ARGUMENT (
"Illegal event: unless event.interpretation is " +
"'MOVE_EVENT' then subject.uri and " +
"subject.current_uri have to be the same");
}
// If subject manifestation and interpretation are not set,
// we try to automatically determine them from the other data.
if (is_empty_string (subject.manifestation))
{
unowned string? manifestation = manifestation_for_uri (
subject.uri);
if (manifestation != null)
subject.manifestation = manifestation;
}
if (is_empty_string (subject.interpretation))
{
unowned string? interpretation = interpretation_for_mimetype (
subject.mimetype);
if (interpretation != null)
subject.interpretation = interpretation;
}
}
}
private uint32 insert_event (Event event) throws EngineError
requires (event.id == 0)
requires (event.num_subjects () > 0)
{
event.id = ++last_id;
// Make sure all the URIs, texts and storage are inserted
{
var uris = new GenericArray<string> ();
var texts = new GenericArray<string> ();
var storages = new GenericArray<string> ();
var subj_uris = new SList<string> ();
if (!is_empty_string (event.origin))
uris.add (event.origin);
// Iterate through subjects and check for validity
for (int i = 0; i < event.num_subjects(); ++i)
{
unowned Subject subject = event.subjects[i];
if (subj_uris.find_custom(subject.uri, strcmp) != null)
{
// Events with two subjects with the same URI are not supported.
warning ("Events with two subjects with the same URI are not supported");
return 0;
}
subj_uris.append (subject.uri);
uris.add (subject.uri);
if (subject.uri != subject.current_uri)
uris.add (subject.current_uri);
if (!is_empty_string (subject.origin))
uris.add (subject.origin);
if (!is_empty_string (subject.text))
texts.add (subject.text);
if (!is_empty_string(subject.storage))
storages.add (subject.storage);
}
try
{
if (uris.length > 0)
database.insert_or_ignore_into_table ("uri", uris);
if (texts.length > 0)
database.insert_or_ignore_into_table ("text", texts);
if (storages.length > 0)
database.insert_or_ignore_into_table ("storage", storages);
}
catch (EngineError e)
{
warning ("Can't insert data for event: " + e.message);
return 0;
}
}
var payload_id = store_payload (event);
// FIXME: Should we add something just like TableLookup but with LRU
// for those? Or is embedding the query faster? Needs testing!
int rc;
unowned Sqlite.Statement insert_stmt = database.event_insertion_stmt;
// We need to call reset here (even if we do so again in the subjects
// loop) since calling .bind_* after a .step() invocation is illegal.
insert_stmt.reset ();
insert_stmt.bind_int64 (1, event.id);
insert_stmt.bind_int64 (2, event.timestamp);
insert_stmt.bind_int64 (3,
interpretations_table.id_for_string (event.interpretation));
insert_stmt.bind_int64 (4,
manifestations_table.id_for_string (event.manifestation));
insert_stmt.bind_int64 (5, actors_table.id_for_string (event.actor));
insert_stmt.bind_text (6, event.origin);
insert_stmt.bind_int64 (7, payload_id);
for (int i = 0; i < event.num_subjects(); ++i)
{
insert_stmt.reset();
unowned Subject subject = event.subjects[i];
insert_stmt.bind_text (8, subject.uri);
insert_stmt.bind_text (9, subject.current_uri);
insert_stmt.bind_int64 (10,
interpretations_table.id_for_string (subject.interpretation));
insert_stmt.bind_int64 (11,
manifestations_table.id_for_string (subject.manifestation));
insert_stmt.bind_text (12, subject.origin);
insert_stmt.bind_int64 (13,
mimetypes_table.id_for_string (subject.mimetype));
insert_stmt.bind_text (14, subject.text);
// FIXME: Consider a storages_table table. Too dangerous?
insert_stmt.bind_text (15, subject.storage);
if ((rc = insert_stmt.step()) != Sqlite.DONE) {
if (rc != Sqlite.CONSTRAINT)
{
database.assert_not_corrupt (rc);
warning ("SQL error: %d, %s\n", rc, db.errmsg ());
return 0;
}
// This event was already registered.
// Rollback last_id and return the ID of the original event
--last_id;
unowned Sqlite.Statement retrieval_stmt =
database.id_retrieval_stmt;
retrieval_stmt.reset ();
retrieval_stmt.bind_int64 (1, event.timestamp);
retrieval_stmt.bind_int64 (2,
interpretations_table.id_for_string (event.interpretation));
retrieval_stmt.bind_int64 (3,
manifestations_table.id_for_string (event.manifestation));
retrieval_stmt.bind_int64 (4, actors_table.id_for_string (event.actor));
if ((rc = retrieval_stmt.step ()) != Sqlite.ROW) {
database.assert_not_corrupt (rc);
warning ("SQL error: %d, %s\n", rc, db.errmsg ());
return 0;
}
return retrieval_stmt.column_int (0);
}
}
if (event.interpretation == ZG.MOVE_EVENT)
{
handle_move_event (event);
}
return event.id;
}
public TimeRange? delete_events (uint32[] event_ids, BusName? sender)
throws EngineError
requires (event_ids.length > 0)
{
event_ids = extension_collection.call_pre_delete_events (
event_ids, sender);
TimeRange? time_range = database.get_time_range_for_event_ids (
event_ids);
string sql_event_ids = database.get_sql_string_from_event_ids (
event_ids);
if (time_range == null)
{
warning ("Tried to delete non-existing event(s): %s".printf (
sql_event_ids));
return null;
}
int rc = db.exec ("DELETE FROM event WHERE id IN (%s)".printf(
sql_event_ids), null, null);
database.assert_query_success (rc, "SQL Error");
message ("Deleted %d (out of %d) events.".printf (
db.changes(), event_ids.length));
extension_collection.call_post_delete_events (event_ids, sender);
return time_range;
}
/**
* Clear all resources Engine is using (close database connection,
* unload extensions, etc.).
*
* After executing this method on an Engine instance, no other function
* of said instance may be called.
*/
public override void close ()
{
// We delete the ExtensionCollection here so that it unloads
// all extensions and they get a chance to access the database
// (including through ExtensionStore) before it's closed.
extension_collection = null;
base.close ();
}
private void handle_move_event (Event event)
{
for (int i = 0; i < event.subjects.length; i++)
{
Subject subject = event.subjects[i];
int rc;
unowned Sqlite.Statement move_stmt = database.move_handling_stmt;
move_stmt.reset();
move_stmt.bind_text (1, subject.current_uri);
move_stmt.bind_text (2, subject.uri);
move_stmt.bind_text (3, event.interpretation);
move_stmt.bind_int64 (4, event.timestamp);
if ((rc = move_stmt.step()) != Sqlite.DONE) {
if (rc != Sqlite.CONSTRAINT)
{
try
{
database.assert_not_corrupt (rc);
}
catch (EngineError err) {}
warning ("SQL error: %d, %s\n", rc, db.errmsg ());
}
}
}
}
private int64 store_payload (Event event)
{
/**
* TODO: Right now payloads are not unique and every event has its
* own one. We could optimize this to store those which are repeated
* for different events only once, especially considering that
* events cannot be modified once they've been inserted.
*/
if (event.payload != null)
{
int rc;
unowned Sqlite.Statement payload_insertion_stmt =
database.payload_insertion_stmt;
payload_insertion_stmt.reset ();
payload_insertion_stmt.bind_blob (1, event.payload.data,
event.payload.data.length);
if ((rc = payload_insertion_stmt.step ()) != Sqlite.DONE)
if (rc != Sqlite.CONSTRAINT)
{
warning ("SQL error: %d, %s\n", rc, db.errmsg ());
try
{
database.assert_not_corrupt (rc);
}
catch (EngineError err) { }
}
return database.database.last_insert_rowid ();
}
return 0;
}
}
}
// vim:expandtab:ts=4:sw=4
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