EnumerateNamedStreams Event

Fires when the OS needs to enumerate a file's named streams.

Syntax

class CBFSEnumerateNamedStreamsEventParams {
public:
  const QString &FileName();
  bool NamedStreamFound();
  void SetNamedStreamFound(bool bNamedStreamFound);
  const QString &StreamName();
  bool SetStreamName(const QString &lpStreamName);
  qint64 StreamSize();
  void SetStreamSize(qint64 lStreamSize);
  qint64 StreamAllocationSize();
  void SetStreamAllocationSize(qint64 lStreamAllocationSize);
  qint64 HandleInfo();
  void *FileContext();
  void SetFileContext(void *lpFileContext);
  void *HandleContext();
  void SetHandleContext(void *lpHandleContext);
  void *EnumerationContext();
  void SetEnumerationContext(void *lpEnumerationContext);
  int ResultCode();
  void SetResultCode(int iResultCode);
  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};
// To handle, connect one or more slots to this signal. void EnumerateNamedStreams(CBFSEnumerateNamedStreamsEventParams *e);
// Or, subclass CBFS and override this emitter function. virtual int FireEnumerateNamedStreams(CBFSEnumerateNamedStreamsEventParams *e) {...}

Remarks

This event fires when the OS needs to enumerate the named streams of the file specified by FileName (which will have been opened via OpenFile).

This event only needs to be handled if the UseAlternateDataStreams property is enabled. To handle this event properly, applications must return information about each of the file's named streams. For each named stream, set StreamNameFound to true and supply the named stream's information using the following parameters:

  • StreamName: Set to the name of the named stream, prefixed with : (e.g. :MyStreamName). For more information about stream naming conventions, refer to Microsoft's Naming Conventions for Streams information.
    • The length of the returned name must not exceed the value of the MaxFileNameLength property.
    • The parameter's setter function will return false if the specified value is too long.
  • StreamSize: Set the size, in bytes, of the named stream's data.
  • StreamAllocationSize: Set to the number of bytes allocated locally for the named stream. This is typically a multiple of the ClusterSize.

If there are no more named streams present, set StreamNameFound to false and leave the above parameters unchanged. When the OS is finished with the named streams enumeration, the CloseNamedStreamsEnumeration event will fire.

The HandleInfo parameter carries a handle to an object with information about the file handle. While within the event handler, it can be used to call any of the following methods: GetHandleCreatorProcessId, GetHandleCreatorProcessName, GetHandleCreatorThreadId, or GetHandleCreatorToken.

The FileContext, HandleContext, and EnumerationContext parameters are placeholders for application-defined data associated with the file, specific handle, and enumeration; respectively. Please refer to the Contexts topic for more information.

The ResultCode parameter will always be 0 when the event is fired. If the event cannot be handled in a "successful" manner for some reason (e.g., a resource isn't available, security checks failed, etc.), set it to a non-zero value to report an appropriate error. Please refer to the Error Reporting and Handling topic for more information.

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CBFS Connect 2020 Qt Edition - Version 20.0 [Build 8348]