GDAL
Public Member Functions | Protected Member Functions | Protected Attributes | List of all members
OGRMutexedDataSource Class Reference

OGRMutexedDataSource class protects all virtual methods of OGRDataSource with a mutex. More...

#include <ogrmutexeddatasource.h>

Inheritance diagram for OGRMutexedDataSource:
OGRDataSource GDALDataset GDALMajorObject

Public Member Functions

 OGRMutexedDataSource (OGRDataSource *poBaseDataSource, int bTakeOwnership, CPLMutex *hMutexIn, int bWrapLayersInMutexedLayer)
 
OGRDataSourceGetBaseDataSource ()
 
virtual const char * GetName ()
 
virtual int GetLayerCount ()
 Get the number of layers in this dataset. More...
 
virtual OGRLayerGetLayer (int)
 Fetch a layer by index. More...
 
virtual OGRLayerGetLayerByName (const char *)
 Fetch a layer by name. More...
 
virtual OGRErr DeleteLayer (int)
 Delete the indicated layer from the datasource. More...
 
virtual int TestCapability (const char *)
 Test if capability is available. More...
 
virtual OGRLayerICreateLayer (const char *pszName, OGRSpatialReference *poSpatialRef=NULL, OGRwkbGeometryType eGType=wkbUnknown, char **papszOptions=NULL)
 This method attempts to create a new layer on the dataset with the indicated name, coordinate system, geometry type. More...
 
virtual OGRLayerCopyLayer (OGRLayer *poSrcLayer, const char *pszNewName, char **papszOptions=NULL)
 Duplicate an existing layer. More...
 
virtual OGRStyleTableGetStyleTable ()
 Returns dataset style table. More...
 
virtual void SetStyleTableDirectly (OGRStyleTable *poStyleTable)
 Set dataset style table. More...
 
virtual void SetStyleTable (OGRStyleTable *poStyleTable)
 Set dataset style table. More...
 
virtual OGRLayerExecuteSQL (const char *pszStatement, OGRGeometry *poSpatialFilter, const char *pszDialect)
 Execute an SQL statement against the data store. More...
 
virtual void ReleaseResultSet (OGRLayer *poResultsSet)
 Release results of ExecuteSQL(). More...
 
virtual void FlushCache ()
 Flush all write cached data to disk. More...
 
virtual OGRErr StartTransaction (int bForce=FALSE)
 For datasources which support transactions, StartTransaction creates a `transaction. More...
 
virtual OGRErr CommitTransaction ()
 For datasources which support transactions, CommitTransaction commits a transaction. More...
 
virtual OGRErr RollbackTransaction ()
 For datasources which support transactions, RollbackTransaction will roll back a datasource to its state before the start of the current transaction. More...
 
virtual char ** GetMetadata (const char *pszDomain="")
 Fetch metadata. More...
 
virtual CPLErr SetMetadata (char **papszMetadata, const char *pszDomain="")
 Set metadata. More...
 
virtual const char * GetMetadataItem (const char *pszName, const char *pszDomain="")
 Fetch single metadata item. More...
 
virtual CPLErr SetMetadataItem (const char *pszName, const char *pszValue, const char *pszDomain="")
 Set single metadata item. More...
 
- Public Member Functions inherited from GDALDataset
virtual ~GDALDataset ()
 Destroy an open GDALDataset. More...
 
int GetRasterXSize (void)
 Fetch raster width in pixels. More...
 
int GetRasterYSize (void)
 Fetch raster height in pixels. More...
 
int GetRasterCount (void)
 Fetch the number of raster bands on this dataset. More...
 
GDALRasterBandGetRasterBand (int)
 Fetch a band object for a dataset. More...
 
virtual const char * GetProjectionRef (void)
 Fetch the projection definition string for this dataset. More...
 
virtual CPLErr SetProjection (const char *)
 Set the projection reference string for this dataset. More...
 
virtual CPLErr GetGeoTransform (double *)
 Fetch the affine transformation coefficients. More...
 
virtual CPLErr SetGeoTransform (double *)
 Set the affine transformation coefficients. More...
 
virtual CPLErr AddBand (GDALDataType eType, char **papszOptions=NULL)
 Add a band to a dataset. More...
 
virtual void * GetInternalHandle (const char *)
 Fetch a format specific internally meaningful handle. More...
 
virtual GDALDriverGetDriver (void)
 Fetch the driver to which this dataset relates. More...
 
virtual char ** GetFileList (void)
 Fetch files forming dataset. More...
 
virtual const char * GetDriverName ()
 
virtual int GetGCPCount ()
 Get number of GCPs. More...
 
virtual const char * GetGCPProjection ()
 Get output projection for GCPs. More...
 
virtual const GDAL_GCPGetGCPs ()
 Fetch GCPs. More...
 
virtual CPLErr SetGCPs (int nGCPCount, const GDAL_GCP *pasGCPList, const char *pszGCPProjection)
 Assign GCPs. More...
 
virtual CPLErr AdviseRead (int nXOff, int nYOff, int nXSize, int nYSize, int nBufXSize, int nBufYSize, GDALDataType eDT, int nBandCount, int *panBandList, char **papszOptions)
 Advise driver of upcoming read requests. More...
 
virtual CPLErr CreateMaskBand (int nFlagsIn)
 Adds a mask band to the dataset. More...
 
virtual GDALAsyncReaderBeginAsyncReader (int nXOff, int nYOff, int nXSize, int nYSize, void *pBuf, int nBufXSize, int nBufYSize, GDALDataType eBufType, int nBandCount, int *panBandMap, int nPixelSpace, int nLineSpace, int nBandSpace, char **papszOptions)
 Sets up an asynchronous data request. More...
 
virtual void EndAsyncReader (GDALAsyncReader *)
 End asynchronous request. More...
 
CPLErr RasterIO (GDALRWFlag, int, int, int, int, void *, int, int, GDALDataType, int, int *, GSpacing, GSpacing, GSpacing, GDALRasterIOExtraArg *psExtraArg) CPL_WARN_UNUSED_RESULT
 Read/write a region of image data from multiple bands. More...
 
int Reference ()
 Add one to dataset reference count. More...
 
int Dereference ()
 Subtract one from dataset reference count. More...
 
GDALAccess GetAccess () const
 
int GetShared ()
 Returns shared flag. More...
 
void MarkAsShared ()
 Mark this dataset as available for sharing.
 
void MarkSuppressOnClose ()
 
char ** GetOpenOptions ()
 
CPLErr BuildOverviews (const char *, int, int *, int, int *, GDALProgressFunc, void *)
 Build raster overview(s) More...
 
void ReportError (CPLErr eErrClass, CPLErrorNum err_no, const char *fmt,...) CPL_PRINT_FUNC_FORMAT(4
 Emits an error related to a dataset. More...
 
virtual OGRLayerCreateLayer (const char *pszName, OGRSpatialReference *poSpatialRef=NULL, OGRwkbGeometryType eGType=wkbUnknown, char **papszOptions=NULL)
 This method attempts to create a new layer on the dataset with the indicated name, coordinate system, geometry type. More...
 
int GetRefCount () const
 Fetch reference count. More...
 
int GetSummaryRefCount () const
 Fetch reference count of datasource and all owned layers. More...
 
OGRErr Release ()
 Drop a reference to this dataset, and if the reference count drops to one close (destroy) the dataset. More...
 
GDALSQLParseInfo * BuildParseInfo (swq_select *psSelectInfo, swq_select_parse_options *poSelectParseOptions)
 
void DestroyParseInfo (GDALSQLParseInfo *psParseInfo)
 
OGRLayerExecuteSQL (const char *pszStatement, OGRGeometry *poSpatialFilter, const char *pszDialect, swq_select_parse_options *poSelectParseOptions)
 
- Public Member Functions inherited from GDALMajorObject
int GetMOFlags ()
 
void SetMOFlags (int nFlagsIn)
 
virtual const char * GetDescription () const
 Fetch object description. More...
 
virtual void SetDescription (const char *)
 Set object description. More...
 
virtual char ** GetMetadataDomainList ()
 Fetch list of metadata domains. More...
 

Protected Member Functions

OGRLayerWrapLayerIfNecessary (OGRLayer *poLayer)
 
- Protected Member Functions inherited from GDALDataset
 GDALDataset (int bForceCachedIO)
 
void RasterInitialize (int, int)
 
void SetBand (int, GDALRasterBand *)
 
virtual CPLErr IBuildOverviews (const char *, int, int *, int, int *, GDALProgressFunc, void *)
 
virtual CPLErr IRasterIO (GDALRWFlag, int, int, int, int, void *, int, int, GDALDataType, int, int *, GSpacing, GSpacing, GSpacing, GDALRasterIOExtraArg *psExtraArg) CPL_WARN_UNUSED_RESULT
 
CPLErr BlockBasedRasterIO (GDALRWFlag, int, int, int, int, void *, int, int, GDALDataType, int, int *, GSpacing, GSpacing, GSpacing, GDALRasterIOExtraArg *psExtraArg) CPL_WARN_UNUSED_RESULT
 
void BlockBasedFlushCache ()
 
CPLErr BandBasedRasterIO (GDALRWFlag eRWFlag, int nXOff, int nYOff, int nXSize, int nYSize, void *pData, int nBufXSize, int nBufYSize, GDALDataType eBufType, int nBandCount, int *panBandMap, GSpacing nPixelSpace, GSpacing nLineSpace, GSpacing nBandSpace, GDALRasterIOExtraArg *psExtraArg) CPL_WARN_UNUSED_RESULT
 
CPLErr RasterIOResampled (GDALRWFlag eRWFlag, int nXOff, int nYOff, int nXSize, int nYSize, void *pData, int nBufXSize, int nBufYSize, GDALDataType eBufType, int nBandCount, int *panBandMap, GSpacing nPixelSpace, GSpacing nLineSpace, GSpacing nBandSpace, GDALRasterIOExtraArg *psExtraArg) CPL_WARN_UNUSED_RESULT
 
CPLErr ValidateRasterIOOrAdviseReadParameters (const char *pszCallingFunc, int *pbStopProcessingOnCENone, int nXOff, int nYOff, int nXSize, int nYSize, int nBufXSize, int nBufYSize, int nBandCount, int *panBandMap)
 
CPLErr TryOverviewRasterIO (GDALRWFlag eRWFlag, int nXOff, int nYOff, int nXSize, int nYSize, void *pData, int nBufXSize, int nBufYSize, GDALDataType eBufType, int nBandCount, int *panBandMap, GSpacing nPixelSpace, GSpacing nLineSpace, GSpacing nBandSpace, GDALRasterIOExtraArg *psExtraArg, int *pbTried)
 
virtual int CloseDependentDatasets ()
 Drop references to any other datasets referenced by this dataset. More...
 
int ValidateLayerCreationOptions (const char *const *papszLCO)
 
int EnterReadWrite (GDALRWFlag eRWFlag)
 
void LeaveReadWrite ()
 
void TemporarilyDropReadWriteLock ()
 
void ReacquireReadWriteLock ()
 
void DisableReadWriteMutex ()
 
int AcquireMutex ()
 
void ReleaseMutex ()
 
OGRErr ProcessSQLCreateIndex (const char *)
 
OGRErr ProcessSQLDropIndex (const char *)
 
OGRErr ProcessSQLDropTable (const char *)
 
OGRErr ProcessSQLAlterTableAddColumn (const char *)
 
OGRErr ProcessSQLAlterTableDropColumn (const char *)
 
OGRErr ProcessSQLAlterTableAlterColumn (const char *)
 
OGRErr ProcessSQLAlterTableRenameColumn (const char *)
 
- Protected Member Functions inherited from GDALMajorObject
char ** BuildMetadataDomainList (char **papszList, int bCheckNonEmpty,...) CPL_NULL_TERMINATED
 Helper function for custom implementations of GetMetadataDomainList() More...
 

Protected Attributes

OGRDataSourcem_poBaseDataSource
 
int m_bHasOwnership
 
CPLMutex * m_hGlobalMutex
 
int m_bWrapLayersInMutexedLayer
 
std::map< OGRLayer *, OGRMutexedLayer * > m_oMapLayers
 
std::map< OGRMutexedLayer *, OGRLayer * > m_oReverseMapLayers
 
- Protected Attributes inherited from GDALDataset
GDALDriverpoDriver
 
GDALAccess eAccess
 
int nRasterXSize
 
int nRasterYSize
 
int nBands
 
GDALRasterBand ** papoBands
 
int nOpenFlags
 
int nRefCount
 
GByte bForceCachedIO
 
GByte bShared
 
GByte bIsInternal
 
GByte bSuppressOnClose
 
GDALDefaultOverviews oOvManager
 
char ** papszOpenOptions
 
OGRStyleTablem_poStyleTable
 
- Protected Attributes inherited from GDALMajorObject
int nFlags
 
CPLString sDescription
 
GDALMultiDomainMetadata oMDMD
 

Additional Inherited Members

- Static Public Member Functions inherited from OGRDataSource
static void DestroyDataSource (OGRDataSource *) OGR_DEPRECATED("Use GDALDataset class instead")
 
- Static Public Member Functions inherited from GDALDataset
static GDALDataset ** GetOpenDatasets (int *pnDatasetCount)
 Fetch all open GDAL dataset handles. More...
 
static int IsGenericSQLDialect (const char *pszDialect)
 

Detailed Description

OGRMutexedDataSource class protects all virtual methods of OGRDataSource with a mutex.

If the passed mutex is NULL, then no locking will be done.

Note that the constructors and destructors are not explicitly protected by the mutex.

Member Function Documentation

OGRErr OGRMutexedDataSource::CommitTransaction ( )
virtual

For datasources which support transactions, CommitTransaction commits a transaction.

If no transaction is active, or the commit fails, will return OGRERR_FAILURE. Datasources which do not support transactions will always return OGRERR_UNSUPPORTED_OPERATION.

Depending on drivers, this may or may not abort layer sequential readings that are active.

This function is the same as the C function GDALDatasetCommitTransaction().

Returns
OGRERR_NONE on success.
Since
GDAL 2.0

Reimplemented from GDALDataset.

OGRLayer * OGRMutexedDataSource::CopyLayer ( OGRLayer poSrcLayer,
const char *  pszNewName,
char **  papszOptions = NULL 
)
virtual

Duplicate an existing layer.

This method creates a new layer, duplicate the field definitions of the source layer and then duplicate each features of the source layer. The papszOptions argument can be used to control driver specific creation options. These options are normally documented in the format specific documentation. The source layer may come from another dataset.

This method is the same as the C function GDALDatasetCopyLayer() and the deprecated OGR_DS_CopyLayer().

In GDAL 1.X, this method used to be in the OGRDataSource class.

Parameters
poSrcLayersource layer.
pszNewNamethe name of the layer to create.
papszOptionsa StringList of name=value options. Options are driver specific. There is a common option to set output layer spatial reference: DST_SRSWKT. The option should be in WKT format.
Returns
an handle to the layer, or NULL if an error occurs.

Reimplemented from GDALDataset.

OGRErr OGRMutexedDataSource::DeleteLayer ( int  iLayer)
virtual

Delete the indicated layer from the datasource.

If this method is supported the ODsCDeleteLayer capability will test TRUE on the GDALDataset.

This method is the same as the C function GDALDatasetDeleteLayer() and the deprecated OGR_DS_DeleteLayer().

In GDAL 1.X, this method used to be in the OGRDataSource class.

Parameters
iLayerthe index of the layer to delete.
Returns
OGRERR_NONE on success, or OGRERR_UNSUPPORTED_OPERATION if deleting layers is not supported for this datasource.

Reimplemented from GDALDataset.

OGRLayer * OGRMutexedDataSource::ExecuteSQL ( const char *  pszStatement,
OGRGeometry poSpatialFilter,
const char *  pszDialect 
)
virtual

Execute an SQL statement against the data store.

The result of an SQL query is either NULL for statements that are in error, or that have no results set, or an OGRLayer pointer representing a results set from the query. Note that this OGRLayer is in addition to the layers in the data store and must be destroyed with ReleaseResultSet() before the dataset is closed (destroyed).

This method is the same as the C function GDALDatasetExecuteSQL() and the deprecated OGR_DS_ExecuteSQL().

For more information on the SQL dialect supported internally by OGR review the OGR SQL document. Some drivers (i.e. Oracle and PostGIS) pass the SQL directly through to the underlying RDBMS.

Starting with OGR 1.10, the SQLITE dialect can also be used.

In GDAL 1.X, this method used to be in the OGRDataSource class.

Parameters
pszStatementthe SQL statement to execute.
poSpatialFiltergeometry which represents a spatial filter. Can be NULL.
pszDialectallows control of the statement dialect. If set to NULL, the OGR SQL engine will be used, except for RDBMS drivers that will use their dedicated SQL engine, unless OGRSQL is explicitly passed as the dialect. Starting with OGR 1.10, the SQLITE dialect can also be used.
Returns
an OGRLayer containing the results of the query. Deallocate with ReleaseResultSet().

Reimplemented from GDALDataset.

void OGRMutexedDataSource::FlushCache ( void  )
virtual

Flush all write cached data to disk.

Any raster (or other GDAL) data written via GDAL calls, but buffered internally will be written to disk.

The default implementation of this method just calls the FlushCache() method on each of the raster bands and the SyncToDisk() method on each of the layers. Conceptionally, calling FlushCache() on a dataset should include any work that might be accomplished by calling SyncToDisk() on layers in that dataset.

Using this method does not prevent use from calling GDALClose() to properly close a dataset and ensure that important data not addressed by FlushCache() is written in the file.

This method is the same as the C function GDALFlushCache().

Reimplemented from GDALDataset.

OGRLayer * OGRMutexedDataSource::GetLayer ( int  iLayer)
virtual

Fetch a layer by index.

The returned layer remains owned by the GDALDataset and should not be deleted by the application.

This method is the same as the C function GDALDatasetGetLayer() and the deprecated OGR_DS_GetLayer().

In GDAL 1.X, this method used to be in the OGRDataSource class.

Parameters
iLayera layer number between 0 and GetLayerCount()-1.
Returns
the layer, or NULL if iLayer is out of range or an error occurs.

Reimplemented from GDALDataset.

OGRLayer * OGRMutexedDataSource::GetLayerByName ( const char *  pszName)
virtual

Fetch a layer by name.

The returned layer remains owned by the GDALDataset and should not be deleted by the application.

This method is the same as the C function GDALDatasetGetLayerByName() and the deprecated OGR_DS_GetLayerByName().

In GDAL 1.X, this method used to be in the OGRDataSource class.

Parameters
pszNamethe layer name of the layer to fetch.
Returns
the layer, or NULL if Layer is not found or an error occurs.

Reimplemented from GDALDataset.

int OGRMutexedDataSource::GetLayerCount ( )
virtual

Get the number of layers in this dataset.

This method is the same as the C function GDALDatasetGetLayerCount(), and the deprecated OGR_DS_GetLayerCount().

In GDAL 1.X, this method used to be in the OGRDataSource class.

Returns
layer count.

Reimplemented from GDALDataset.

char ** OGRMutexedDataSource::GetMetadata ( const char *  pszDomain = "")
virtual

Fetch metadata.

The returned string list is owned by the object, and may change at any time. It is formatted as a "Name=value" list with the last pointer value being NULL. Use the CPL StringList functions such as CSLFetchNameValue() to manipulate it.

Note that relatively few formats return any metadata at this time.

This method does the same thing as the C function GDALGetMetadata().

Parameters
pszDomainthe domain of interest. Use "" or NULL for the default domain.
Returns
NULL or a string list.

Reimplemented from GDALMajorObject.

const char * OGRMutexedDataSource::GetMetadataItem ( const char *  pszName,
const char *  pszDomain = "" 
)
virtual

Fetch single metadata item.

The C function GDALGetMetadataItem() does the same thing as this method.

Parameters
pszNamethe key for the metadata item to fetch.
pszDomainthe domain to fetch for, use NULL for the default domain.
Returns
NULL on failure to find the key, or a pointer to an internal copy of the value string on success.

Reimplemented from GDALMajorObject.

OGRStyleTable * OGRMutexedDataSource::GetStyleTable ( )
virtual

Returns dataset style table.

This method is the same as the C function GDALDatasetGetStyleTable() and the deprecated OGR_DS_GetStyleTable().

In GDAL 1.X, this method used to be in the OGRDataSource class.

Returns
pointer to a style table which should not be modified or freed by the caller.

Reimplemented from GDALDataset.

OGRLayer * OGRMutexedDataSource::ICreateLayer ( const char *  pszName,
OGRSpatialReference poSpatialRef = NULL,
OGRwkbGeometryType  eGType = wkbUnknown,
char **  papszOptions = NULL 
)
virtual

This method attempts to create a new layer on the dataset with the indicated name, coordinate system, geometry type.

This method is reserved to implementation by drivers.

The papszOptions argument can be used to control driver specific creation options. These options are normally documented in the format specific documentation.

Parameters
pszNamethe name for the new layer. This should ideally not match any existing layer on the datasource.
poSpatialRefthe coordinate system to use for the new layer, or NULL if no coordinate system is available.
eGTypethe geometry type for the layer. Use wkbUnknown if there are no constraints on the types geometry to be written.
papszOptionsa StringList of name=value options. Options are driver specific.
Returns
NULL is returned on failure, or a new OGRLayer handle on success.
Since
GDAL 2.0

Reimplemented from GDALDataset.

void OGRMutexedDataSource::ReleaseResultSet ( OGRLayer poResultsSet)
virtual

Release results of ExecuteSQL().

This method should only be used to deallocate OGRLayers resulting from an ExecuteSQL() call on the same GDALDataset. Failure to deallocate a results set before destroying the GDALDataset may cause errors.

This method is the same as the C function GDALDatasetReleaseResultSet() and the deprecated OGR_DS_ReleaseResultSet().

In GDAL 1.X, this method used to be in the OGRDataSource class.

Parameters
poResultsSetthe result of a previous ExecuteSQL() call.

Reimplemented from GDALDataset.

OGRErr OGRMutexedDataSource::RollbackTransaction ( )
virtual

For datasources which support transactions, RollbackTransaction will roll back a datasource to its state before the start of the current transaction.

If no transaction is active, or the rollback fails, will return OGRERR_FAILURE. Datasources which do not support transactions will always return OGRERR_UNSUPPORTED_OPERATION.

This function is the same as the C function GDALDatasetRollbackTransaction().

Returns
OGRERR_NONE on success.
Since
GDAL 2.0

Reimplemented from GDALDataset.

CPLErr OGRMutexedDataSource::SetMetadata ( char **  papszMetadataIn,
const char *  pszDomain = "" 
)
virtual

Set metadata.

The C function GDALSetMetadata() does the same thing as this method.

Parameters
papszMetadataInthe metadata in name=value string list format to apply.
pszDomainthe domain of interest. Use "" or NULL for the default domain.
Returns
CE_None on success, CE_Failure on failure and CE_Warning if the metadata has been accepted, but is likely not maintained persistently by the underlying object between sessions.

Reimplemented from GDALMajorObject.

CPLErr OGRMutexedDataSource::SetMetadataItem ( const char *  pszName,
const char *  pszValue,
const char *  pszDomain = "" 
)
virtual

Set single metadata item.

The C function GDALSetMetadataItem() does the same thing as this method.

Parameters
pszNamethe key for the metadata item to fetch.
pszValuethe value to assign to the key.
pszDomainthe domain to set within, use NULL for the default domain.
Returns
CE_None on success, or an error code on failure.

Reimplemented from GDALMajorObject.

void OGRMutexedDataSource::SetStyleTable ( OGRStyleTable poStyleTable)
virtual

Set dataset style table.

This method operate exactly as SetStyleTableDirectly() except that it does not assume ownership of the passed table.

This method is the same as the C function GDALDatasetSetStyleTable() and the deprecated OGR_DS_SetStyleTable().

In GDAL 1.X, this method used to be in the OGRDataSource class.

Parameters
poStyleTablepointer to style table to set

Reimplemented from GDALDataset.

void OGRMutexedDataSource::SetStyleTableDirectly ( OGRStyleTable poStyleTable)
virtual

Set dataset style table.

This method operate exactly as SetStyleTable() except that it assumes ownership of the passed table.

This method is the same as the C function GDALDatasetSetStyleTableDirectly() and the deprecated OGR_DS_SetStyleTableDirectly().

In GDAL 1.X, this method used to be in the OGRDataSource class.

Parameters
poStyleTablepointer to style table to set

Reimplemented from GDALDataset.

OGRErr OGRMutexedDataSource::StartTransaction ( int  bForce = FALSE)
virtual

For datasources which support transactions, StartTransaction creates a `transaction.

If starting the transaction fails, will return OGRERR_FAILURE. Datasources which do not support transactions will always return OGRERR_UNSUPPORTED_OPERATION.

Nested transactions are not supported.

All changes done after the start of the transaction are definitely applied in the datasource if CommitTransaction() is called. They may be canceled by calling RollbackTransaction() instead.

At the time of writing, transactions only apply on vector layers.

Datasets that support transactions will advertise the ODsCTransactions capability. Use of transactions at dataset level is generally preferred to transactions at layer level, whose scope is rarely limited to the layer from which it was started.

In case StartTransaction() fails, neither CommitTransaction() or RollbackTransaction() should be called.

If an error occurs after a successful StartTransaction(), the whole transaction may or may not be implicitly canceled, depending on drivers. (e.g. the PG driver will cancel it, SQLite/GPKG not). In any case, in the event of an error, an explicit call to RollbackTransaction() should be done to keep things balanced.

By default, when bForce is set to FALSE, only "efficient" transactions will be attempted. Some drivers may offer an emulation of transactions, but sometimes with significant overhead, in which case the user must explicitly allow for such an emulation by setting bForce to TRUE. Drivers that offer emulated transactions should advertise the ODsCEmulatedTransactions capability (and not ODsCTransactions).

This function is the same as the C function GDALDatasetStartTransaction().

Parameters
bForcecan be set to TRUE if an emulation, possibly slow, of a transaction mechanism is acceptable.
Returns
OGRERR_NONE on success.
Since
GDAL 2.0

Reimplemented from GDALDataset.

int OGRMutexedDataSource::TestCapability ( const char *  pszCap)
virtual

Test if capability is available.

One of the following dataset capability names can be passed into this method, and a TRUE or FALSE value will be returned indicating whether or not the capability is available for this object.

  • ODsCCreateLayer: True if this datasource can create new layers.

  • ODsCDeleteLayer: True if this datasource can delete existing layers.

  • ODsCCreateGeomFieldAfterCreateLayer: True if the layers of this datasource support CreateGeomField() just after layer creation.

  • ODsCCurveGeometries: True if this datasource supports curve geometries.

  • ODsCTransactions: True if this datasource supports (efficient) transactions.

  • ODsCEmulatedTransactions: True if this datasource supports transactions through emulation.

The #define macro forms of the capability names should be used in preference to the strings themselves to avoid misspelling.

This method is the same as the C function GDALDatasetTestCapability() and the deprecated OGR_DS_TestCapability().

In GDAL 1.X, this method used to be in the OGRDataSource class.

Parameters
pszCapthe capability to test.
Returns
TRUE if capability available otherwise FALSE.

Reimplemented from GDALDataset.


The documentation for this class was generated from the following files:

Generated for GDAL by doxygen 1.8.9.1.