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arangodb/arangod/VocBase/Ditch.cpp

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////////////////////////////////////////////////////////////////////////////////
/// @brief ditches for documents, datafiles etc.
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2014 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Dr. Frank Celler
/// @author Copyright 2014, ArangoDB GmbH, Cologne, Germany
/// @author Copyright 2011-2013, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
#include "Ditch.h"
#include "Basics/logging.h"
#include "Basics/MutexLocker.h"
#include "VocBase/document-collection.h"
using namespace triagens::arango;
// -----------------------------------------------------------------------------
// --SECTION-- class Ditch
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- constructors / destructors
// -----------------------------------------------------------------------------
Ditch::Ditch (Ditches* ditches,
char const* filename,
int line)
: _ditches(ditches),
_prev(nullptr),
_next(nullptr),
_filename(filename),
_line(line) {
}
Ditch::~Ditch () {
}
// -----------------------------------------------------------------------------
// --SECTION-- public methods
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief return the associated collection
////////////////////////////////////////////////////////////////////////////////
TRI_document_collection_t* Ditch::collection () const {
return _ditches->collection();
}
// -----------------------------------------------------------------------------
// --SECTION-- class DocumentDitch
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- constructors / destructors
// -----------------------------------------------------------------------------
DocumentDitch::DocumentDitch (Ditches* ditches,
bool usedByTransaction,
char const* filename,
int line)
: Ditch(ditches, filename, line),
_usedByExternal(0),
_usedByTransaction(usedByTransaction) {
}
DocumentDitch::~DocumentDitch () {
}
////////////////////////////////////////////////////////////////////////////////
/// @brief sets the _usedByTransaction flag, using the required lock
////////////////////////////////////////////////////////////////////////////////
void DocumentDitch::setUsedByTransaction () {
auto callback = [this] () -> void {
_usedByTransaction = true;
};
_ditches->executeProtected(callback);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief increases the _usedByExternal value, using the required lock
////////////////////////////////////////////////////////////////////////////////
void DocumentDitch::setUsedByExternal () {
auto callback = [this] () -> void {
++_usedByExternal;
};
_ditches->executeProtected(callback);
}
// -----------------------------------------------------------------------------
// --SECTION-- class ReplicationDitch
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- constructors / destructors
// -----------------------------------------------------------------------------
ReplicationDitch::ReplicationDitch (Ditches* ditches,
char const* filename,
int line)
: Ditch(ditches, filename, line) {
}
ReplicationDitch::~ReplicationDitch () {
}
// -----------------------------------------------------------------------------
// --SECTION-- class CompactionDitch
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- constructors / destructors
// -----------------------------------------------------------------------------
CompactionDitch::CompactionDitch (Ditches* ditches,
char const* filename,
int line)
: Ditch(ditches, filename, line) {
}
CompactionDitch::~CompactionDitch () {
}
// -----------------------------------------------------------------------------
// --SECTION-- class DropDatafileDitch
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- constructors / destructors
// -----------------------------------------------------------------------------
DropDatafileDitch::DropDatafileDitch (Ditches* ditches,
TRI_datafile_t* datafile,
void* data,
std::function<void(TRI_datafile_t*, void*)> callback,
char const* filename,
int line)
: Ditch(ditches, filename, line),
_datafile(datafile),
_data(data),
_callback(callback) {
}
DropDatafileDitch::~DropDatafileDitch () {
}
// -----------------------------------------------------------------------------
// --SECTION-- class RenameDatafileDitch
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- constructors / destructors
// -----------------------------------------------------------------------------
RenameDatafileDitch::RenameDatafileDitch (Ditches* ditches,
TRI_datafile_t* datafile,
void* data,
std::function<void(TRI_datafile_t*, void*)> callback,
char const* filename,
int line)
: Ditch(ditches, filename, line),
_datafile(datafile),
_data(data),
_callback(callback) {
}
RenameDatafileDitch::~RenameDatafileDitch () {
}
// -----------------------------------------------------------------------------
// --SECTION-- class UnloadCollectionDitch
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- constructors / destructors
// -----------------------------------------------------------------------------
UnloadCollectionDitch::UnloadCollectionDitch (Ditches* ditches,
TRI_collection_t* collection,
void* data,
std::function<bool(TRI_collection_t*, void*)> callback,
char const* filename,
int line)
: Ditch(ditches, filename, line),
_collection(collection),
_data(data),
_callback(callback) {
}
UnloadCollectionDitch::~UnloadCollectionDitch () {
}
// -----------------------------------------------------------------------------
// --SECTION-- class DropCollectionDitch
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- constructors / destructors
// -----------------------------------------------------------------------------
DropCollectionDitch::DropCollectionDitch (Ditches* ditches,
TRI_collection_t* collection,
void* data,
std::function<bool(TRI_collection_t*, void*)> callback,
char const* filename,
int line)
: Ditch(ditches, filename, line),
_collection(collection),
_data(data),
_callback(callback) {
}
DropCollectionDitch::~DropCollectionDitch () {
}
// -----------------------------------------------------------------------------
// --SECTION-- class Ditches
// -----------------------------------------------------------------------------
Ditches::Ditches (TRI_document_collection_t* collection)
: _collection(collection),
_lock(),
_begin(nullptr),
_end(nullptr),
_numDocumentDitches(0) {
TRI_ASSERT(_collection != nullptr);
}
Ditches::~Ditches () {
}
// -----------------------------------------------------------------------------
// --SECTION-- public methods
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief destroy the ditches - to be called on shutdown only
////////////////////////////////////////////////////////////////////////////////
void Ditches::destroy () {
auto* ptr = _begin;
while (ptr != nullptr) {
auto* next = ptr->next();
auto const type = ptr->type();
if (type == Ditch::TRI_DITCH_COLLECTION_UNLOAD ||
type == Ditch::TRI_DITCH_COLLECTION_DROP ||
type == Ditch::TRI_DITCH_DATAFILE_DROP ||
type == Ditch::TRI_DITCH_DATAFILE_RENAME ||
type == Ditch::TRI_DITCH_REPLICATION ||
type == Ditch::TRI_DITCH_COMPACTION) {
delete ptr;
}
else if (type == Ditch::TRI_DITCH_DOCUMENT) {
LOG_ERROR("logic error. shouldn't have document ditches on unload");
}
else {
LOG_ERROR("unknown ditch type");
}
ptr = next;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief return the associated collection
////////////////////////////////////////////////////////////////////////////////
TRI_document_collection_t* Ditches::collection () const {
return _collection;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief run a user-defined function under the lock
////////////////////////////////////////////////////////////////////////////////
void Ditches::executeProtected (std::function<void()> callback) {
MUTEX_LOCKER(_lock);
callback();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief process the first element from the list
/// the list will remain unchanged if the first element is either a
/// DocumentDitch, a ReplicationDitch or a CompactionDitch, or if the list
/// contains any DocumentDitches.
////////////////////////////////////////////////////////////////////////////////
Ditch* Ditches::process (bool& popped,
std::function<bool(Ditch const*)> callback) {
popped = false;
MUTEX_LOCKER(_lock);
auto ditch = _begin;
if (ditch == nullptr) {
// nothing to do
return nullptr;
}
TRI_ASSERT(ditch != nullptr);
auto const type = ditch->type();
// if it is a DocumentDitch, it means that there is still a reference held
// to document data in a datafile. We must then not unload or remove a file
if (type == Ditch::TRI_DITCH_DOCUMENT ||
type == Ditch::TRI_DITCH_REPLICATION ||
type == Ditch::TRI_DITCH_COMPACTION ||
_numDocumentDitches > 0) {
// did not find anything at the head of the barrier list or found an element marker
// this means we must exit and cannot throw away datafiles and can unload collections
return nullptr;
}
// no DocumentDitch at the head of the ditches list. This means that there is
// some other action we can perform (i.e. unloading a datafile or a collection)
// note that there is no need to check the entire list for a DocumentDitch as
// the list is filled up in chronological order. New ditches are always added to the
// tail of the list, and if we have the following list
// HEAD -> TRI_DITCH_DATAFILE_CALLBACK -> TRI_DITCH_DOCUMENT
// then it is still safe to execute the datafile callback operation, even if there
// is a TRI_DITCH_DOCUMENT after it.
// This is the case because the TRI_DITCH_DATAFILE_CALLBACK is only put into the
// ditches list after changing the pointers in all headers. After the pointers are
// changed, it is safe to unload/remove an old datafile (that noone points to). And
// any newer TRI_DITCH_DOCUMENTs will always reference data inside other datafiles.
if (! callback(ditch)) {
return ditch;
}
// found an element to go on with - now unlink the element from the list
unlink(ditch);
popped = true;
return ditch;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief check whether the ditches contain a ditch of a certain type
////////////////////////////////////////////////////////////////////////////////
bool Ditches::contains (Ditch::DitchType type) {
MUTEX_LOCKER(_lock);
if (type == Ditch::TRI_DITCH_DOCUMENT) {
// shortcut
return (_numDocumentDitches > 0);
}
auto const* ptr = _begin;
while (ptr != nullptr) {
if (ptr->type() == type) {
return true;
}
ptr = ptr->_next;
}
return false;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief removes and frees a ditch
////////////////////////////////////////////////////////////////////////////////
void Ditches::freeDitch (Ditch* ditch) {
TRI_ASSERT(ditch != nullptr);
{
MUTEX_LOCKER(_lock);
unlink(ditch);
if (ditch->type() == Ditch::TRI_DITCH_DOCUMENT) {
// decrease counter
--_numDocumentDitches;
}
}
delete ditch;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief removes and frees a ditch
/// this is used for ditches used by transactions or by externals to protect
/// the flags by the lock
////////////////////////////////////////////////////////////////////////////////
void Ditches::freeDocumentDitch (DocumentDitch* ditch,
bool fromTransaction) {
TRI_ASSERT(ditch != nullptr);
bool shouldFree = false;
{
MUTEX_LOCKER(_lock); // FIX_MUTEX
// First see who might still be using the ditch:
if (fromTransaction) {
TRI_ASSERT(ditch->_usedByTransaction == true);
ditch->_usedByTransaction = false;
}
else {
// note: _usedByExternal may or may not be set when we get here
// the reason is that there are ditches not linked at all
// (when a ditch is created ahead of operations but the operations are
// not executed etc.)
if (ditch->_usedByExternal > 0) {
--ditch->_usedByExternal;
}
}
if (ditch->_usedByTransaction == false &&
ditch->_usedByExternal == 0) {
// Really free it:
unlink(ditch);
// decrease counter
--_numDocumentDitches;
// free the ditch
shouldFree = true;
}
}
if (shouldFree) {
delete ditch;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief creates a new document ditch and links it
////////////////////////////////////////////////////////////////////////////////
DocumentDitch* Ditches::createDocumentDitch (bool usedByTransaction,
char const* filename,
int line) {
try {
auto ditch = new DocumentDitch(this, usedByTransaction, filename, line);
link(ditch);
return ditch;
}
catch (...) {
return nullptr;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief creates a new replication ditch and links it
////////////////////////////////////////////////////////////////////////////////
ReplicationDitch* Ditches::createReplicationDitch (char const* filename,
int line) {
try {
auto ditch = new ReplicationDitch(this, filename, line);
link(ditch);
return ditch;
}
catch (...) {
return nullptr;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief creates a new compaction ditch and links it
////////////////////////////////////////////////////////////////////////////////
CompactionDitch* Ditches::createCompactionDitch (char const* filename,
int line) {
try {
auto ditch = new CompactionDitch(this, filename, line);
link(ditch);
return ditch;
}
catch (...) {
return nullptr;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief creates a new datafile deletion ditch
////////////////////////////////////////////////////////////////////////////////
DropDatafileDitch* Ditches::createDropDatafileDitch (TRI_datafile_t* datafile,
void* data,
std::function<void(struct TRI_datafile_s*, void*)> callback,
char const* filename,
int line) {
try {
auto ditch = new DropDatafileDitch(this, datafile, data, callback, filename, line);
link(ditch);
return ditch;
}
catch (...) {
return nullptr;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief creates a new datafile rename ditch
////////////////////////////////////////////////////////////////////////////////
RenameDatafileDitch* Ditches::createRenameDatafileDitch (TRI_datafile_t* datafile,
void* data,
std::function<void(struct TRI_datafile_s*, void*)> callback,
char const* filename,
int line) {
try {
auto ditch = new RenameDatafileDitch(this, datafile, data, callback, filename, line);
link(ditch);
return ditch;
}
catch (...) {
return nullptr;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief creates a new collection unload ditch
////////////////////////////////////////////////////////////////////////////////
UnloadCollectionDitch* Ditches::createUnloadCollectionDitch (TRI_collection_t* collection,
void* data,
std::function<bool(TRI_collection_t*, void*)> callback,
char const* filename,
int line) {
try {
auto ditch = new UnloadCollectionDitch(this, collection, data, callback, filename, line);
link(ditch);
return ditch;
}
catch (...) {
return nullptr;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief creates a new datafile drop ditch
////////////////////////////////////////////////////////////////////////////////
DropCollectionDitch* Ditches::createDropCollectionDitch (TRI_collection_t* collection,
void* data,
std::function<bool(TRI_collection_t*, void*)> callback,
char const* filename,
int line) {
try {
auto ditch = new DropCollectionDitch(this, collection, data, callback, filename, line);
link(ditch);
return ditch;
}
catch (...) {
return nullptr;
}
}
// -----------------------------------------------------------------------------
// --SECTION-- private methods
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief inserts the ditch into the linked list of ditches
////////////////////////////////////////////////////////////////////////////////
void Ditches::link (Ditch* ditch) {
TRI_ASSERT(ditch != nullptr);
MUTEX_LOCKER(_lock); // FIX_MUTEX
// empty list
if (_end == nullptr) {
ditch->_next = nullptr;
ditch->_prev = nullptr;
_begin = ditch;
_end = ditch;
}
// add to the end
else {
ditch->_next = nullptr;
ditch->_prev = _end;
_end->_next = ditch;
_end = ditch;
}
if (ditch->type() == Ditch::TRI_DITCH_DOCUMENT) {
// increase counter
++_numDocumentDitches;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief unlinks the ditch from the linked list of ditches
////////////////////////////////////////////////////////////////////////////////
void Ditches::unlink (Ditch* ditch) {
// ditch is at the beginning of the chain
if (ditch->_prev == nullptr) {
_begin = ditch->_next;
}
else {
ditch->_prev->_next = ditch->_next;
}
// ditch is at the end of the chain
if (ditch->_next == nullptr) {
_end = ditch->_prev;
}
else {
ditch->_next->_prev = ditch->_prev;
}
}
// -----------------------------------------------------------------------------
// --SECTION-- END-OF-FILE
// -----------------------------------------------------------------------------
// Local Variables:
// mode: outline-minor
// outline-regexp: "/// @brief\\|/// {@inheritDoc}\\|/// @page\\|// --SECTION--\\|/// @\\}"
// End:
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