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CPipe Class Reference

#include <CPipe.h>

Collaboration diagram for CPipe:
Collaboration graph
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Public Member Functions

 CPipe ()
 
 ~CPipe ()
 
void CloseReadPipe ()
 
void CloseWritePipe ()
 
bool Peek (PVOID Buffer, DWORD BufferSize, PDWORD BytesRead, PDWORD TotalBytesAvailable)
 
DWORD Read (PVOID Buffer, DWORD NumberOfBytesToRead, PDWORD NumberOfBytesRead, DWORD TimeoutMilliseconds)
 
bool Write (LPCVOID Buffer, DWORD NumberOfBytesToWrite, PDWORD NumberOfBytesWritten)
 

Private Attributes

OVERLAPPED m_ReadOverlapped
 
HANDLE m_hReadPipe
 
HANDLE m_hWritePipe
 

Static Private Attributes

static LONG m_lPipeCount = 0
 

Friends

class CPipedProcess
 

Detailed Description

Definition at line 9 of file CPipe.h.

Constructor & Destructor Documentation

◆ CPipe()

CPipe::CPipe ( )

Constructs a CPipe object and initializes read and write handles.

Definition at line 17 of file CPipe.cpp.

18{
19 SECURITY_ATTRIBUTES SecurityAttributes;
20
21 SecurityAttributes.nLength = sizeof(SecurityAttributes);
22 SecurityAttributes.bInheritHandle = TRUE;
23 SecurityAttributes.lpSecurityDescriptor = NULL;
24
25 // Construct a unique pipe name.
26 WCHAR wszPipeName[MAX_PATH];
27 InterlockedIncrement(&m_lPipeCount);
28 swprintf(wszPipeName, L"\\\\.\\pipe\\TestmanPipe%ld", m_lPipeCount);
29
30 // Create a named pipe with the default settings, but overlapped (asynchronous) operations.
31 // Latter feature is why we can't simply use CreatePipe.
32 const DWORD dwDefaultBufferSize = 4096;
33 const DWORD dwDefaultTimeoutMilliseconds = 120000;
34
35 m_hReadPipe = CreateNamedPipeW(wszPipeName,
36 PIPE_ACCESS_INBOUND | FILE_FLAG_OVERLAPPED,
37 PIPE_TYPE_BYTE | PIPE_READMODE_BYTE | PIPE_WAIT,
38 1,
39 dwDefaultBufferSize,
40 dwDefaultBufferSize,
41 dwDefaultTimeoutMilliseconds,
42 &SecurityAttributes);
43 if (m_hReadPipe == INVALID_HANDLE_VALUE)
44 {
45 FATAL("CreateNamedPipe failed\n");
46 }
47
48 // Use CreateFileW to get the write handle to the pipe.
49 // Writing is done synchronously, so no FILE_FLAG_OVERLAPPED here!
50 m_hWritePipe = CreateFileW(wszPipeName,
51 GENERIC_WRITE,
52 0,
53 &SecurityAttributes,
54 OPEN_EXISTING,
55 FILE_ATTRIBUTE_NORMAL,
56 NULL);
57 if (m_hWritePipe == INVALID_HANDLE_VALUE)
58 {
59 FATAL("CreateFileW failed\n");
60 }
61
62 // Prepare the OVERLAPPED structure for reading.
63 ZeroMemory(&m_ReadOverlapped, sizeof(m_ReadOverlapped));
64 m_ReadOverlapped.hEvent = CreateEventW(NULL, TRUE, TRUE, NULL);
65 if (!m_ReadOverlapped.hEvent)
66 {
67 FATAL("CreateEvent failed\n");
68 }
69}
InterlockedIncrement
#define InterlockedIncrement
Definition: armddk.h:53
CPipe::m_hWritePipe
HANDLE m_hWritePipe
Definition: CPipe.h:16
CPipe::m_lPipeCount
static LONG m_lPipeCount
Definition: CPipe.h:12
CPipe::m_ReadOverlapped
OVERLAPPED m_ReadOverlapped
Definition: CPipe.h:14
CPipe::m_hReadPipe
HANDLE m_hReadPipe
Definition: CPipe.h:15
NULL
#define NULL
Definition: types.h:112
TRUE
#define TRUE
Definition: types.h:120
OPEN_EXISTING
#define OPEN_EXISTING
Definition: compat.h:775
INVALID_HANDLE_VALUE
#define INVALID_HANDLE_VALUE
Definition: compat.h:731
MAX_PATH
#define MAX_PATH
Definition: compat.h:34
CreateFileW
#define CreateFileW
Definition: compat.h:741
FILE_ATTRIBUTE_NORMAL
#define FILE_ATTRIBUTE_NORMAL
Definition: compat.h:137
swprintf
#define swprintf
Definition: precomp.h:40
L
#define L(x)
Definition: resources.c:13
DWORD
unsigned long DWORD
Definition: ntddk_ex.h:95
ZeroMemory
#define ZeroMemory
Definition: minwinbase.h:31
FILE_FLAG_OVERLAPPED
#define FILE_FLAG_OVERLAPPED
Definition: disk.h:46
FATAL
#define FATAL(Message)
Definition: precomp.h:59
CreateNamedPipeW
HANDLE WINAPI CreateNamedPipeW(LPCWSTR lpName, DWORD dwOpenMode, DWORD dwPipeMode, DWORD nMaxInstances, DWORD nOutBufferSize, DWORD nInBufferSize, DWORD nDefaultTimeOut, LPSECURITY_ATTRIBUTES lpSecurityAttributes)
Definition: npipe.c:246
GENERIC_WRITE
#define GENERIC_WRITE
Definition: nt_native.h:90
_OVERLAPPED::hEvent
HANDLE hEvent
Definition: minwinbase.h:230
_SECURITY_ATTRIBUTES
Definition: compat.h:191
_SECURITY_ATTRIBUTES::nLength
DWORD nLength
Definition: compat.h:192
_SECURITY_ATTRIBUTES::bInheritHandle
BOOL bInheritHandle
Definition: compat.h:194
_SECURITY_ATTRIBUTES::lpSecurityDescriptor
LPVOID lpSecurityDescriptor
Definition: compat.h:193
CreateEventW
HANDLE WINAPI DECLSPEC_HOTPATCH CreateEventW(IN LPSECURITY_ATTRIBUTES lpEventAttributes OPTIONAL, IN BOOL bManualReset, IN BOOL bInitialState, IN LPCWSTR lpName OPTIONAL)
Definition: synch.c:651
PIPE_ACCESS_INBOUND
#define PIPE_ACCESS_INBOUND
Definition: winbase.h:167
PIPE_READMODE_BYTE
#define PIPE_READMODE_BYTE
Definition: winbase.h:171
PIPE_WAIT
#define PIPE_WAIT
Definition: winbase.h:173
PIPE_TYPE_BYTE
#define PIPE_TYPE_BYTE
Definition: winbase.h:169
WCHAR
__wchar_t WCHAR
Definition: xmlstorage.h:180

◆ ~CPipe()

CPipe::~CPipe ( )

Destructs a CPipe object and closes all open handles.

Definition at line 74 of file CPipe.cpp.

75{
76 if (m_hReadPipe)
77 CloseHandle(m_hReadPipe);
78 if (m_hWritePipe)
79 CloseHandle(m_hWritePipe);
80}
CloseHandle
#define CloseHandle
Definition: compat.h:739

Member Function Documentation

◆ CloseReadPipe()

void CPipe::CloseReadPipe ( )

Closes a CPipe's read pipe, leaving the write pipe unchanged.

Definition at line 86 of file CPipe.cpp.

87{
88 if (!m_hReadPipe)
89 FATAL("Trying to close already closed read pipe\n");
90 CloseHandle(m_hReadPipe);
91 m_hReadPipe = NULL;
92}

◆ CloseWritePipe()

void CPipe::CloseWritePipe ( )

Closes a CPipe's write pipe, leaving the read pipe unchanged.

Definition at line 98 of file CPipe.cpp.

99{
100 if (!m_hWritePipe)
101 FATAL("Trying to close already closed write pipe\n");
102 CloseHandle(m_hWritePipe);
103 m_hWritePipe = NULL;
104}

◆ Peek()

bool CPipe::Peek ( PVOID  Buffer,
DWORD  BufferSize,
PDWORD  BytesRead,
PDWORD  TotalBytesAvailable 
)

Reads data from a pipe without advancing the read offset and/or retrieves information about available data.

This function must not be called after CloseReadPipe.

Parameters
BufferAn optional buffer to read pipe data into.
BufferSizeThe size of the buffer specified in Buffer, or 0 if no read should be performed.
BytesReadOn return, the number of bytes actually read from the pipe into Buffer.
TotalBytesAvailableOn return, the total number of bytes available to read from the pipe.
Returns
True on success, false on failure; call GetLastError for error information.
See also
PeekNamedPipe

Definition at line 129 of file CPipe.cpp.

130{
131 if (!m_hReadPipe)
132 FATAL("Trying to peek from a closed read pipe\n");
133
134 return PeekNamedPipe(m_hReadPipe, Buffer, BufferSize, BytesRead, TotalBytesAvailable, NULL);
135}
Buffer
Definition: bufpool.h:45
PeekNamedPipe
BOOL WINAPI PeekNamedPipe(HANDLE hNamedPipe, LPVOID lpBuffer, DWORD nBufferSize, LPDWORD lpBytesRead, LPDWORD lpTotalBytesAvail, LPDWORD lpBytesLeftThisMessage)
Definition: npipe.c:1214
BytesRead
_Must_inspect_result_ _In_ WDFIOTARGET _In_opt_ WDFREQUEST _In_opt_ PWDF_MEMORY_DESCRIPTOR _In_opt_ PLONGLONG _In_opt_ PWDF_REQUEST_SEND_OPTIONS _Out_opt_ PULONG_PTR BytesRead
Definition: wdfiotarget.h:870
BufferSize
_In_ WDFMEMORY _Out_opt_ size_t * BufferSize
Definition: wdfmemory.h:254

◆ Read()

DWORD CPipe::Read ( PVOID  Buffer,
DWORD  NumberOfBytesToRead,
PDWORD  NumberOfBytesRead,
DWORD  TimeoutMilliseconds 
)

Reads data from the read pipe, advancing the read offset accordingly.

This function must not be called after CloseReadPipe.

Parameters
BufferBuffer to read pipe data into.
NumberOfBytesToReadThe number of bytes to read into Buffer.
NumberOfBytesReadOn return, the number of bytes actually read from the pipe into Buffer.
Returns
Returns a Win32 error code. Expected error codes include:
  • ERROR_SUCCESS: The read has completed successfully.
  • WAIT_TIMEOUT: The given timeout has elapsed before any data was read.
  • ERROR_BROKEN_PIPE: The other end of the pipe has been closed.
See also
ReadFile

Definition at line 160 of file CPipe.cpp.

161{
162 if (!m_hReadPipe)
163 {
164 FATAL("Trying to read from a closed read pipe\n");
165 }
166
167 if (ReadFile(m_hReadPipe, Buffer, NumberOfBytesToRead, NumberOfBytesRead, &m_ReadOverlapped))
168 {
169 // The asynchronous read request could be satisfied immediately.
170 return ERROR_SUCCESS;
171 }
172
173 DWORD dwLastError = GetLastError();
174 if (dwLastError == ERROR_IO_PENDING)
175 {
176 // The asynchronous read request could not be satisfied immediately, so wait for it with the given timeout.
177 DWORD dwWaitResult = WaitForSingleObject(m_ReadOverlapped.hEvent, TimeoutMilliseconds);
178 if (dwWaitResult == WAIT_OBJECT_0)
179 {
180 // Fill NumberOfBytesRead.
181 if (GetOverlappedResult(m_hReadPipe, &m_ReadOverlapped, NumberOfBytesRead, FALSE))
182 {
183 // We successfully read NumberOfBytesRead bytes.
184 return ERROR_SUCCESS;
185 }
186
187 dwLastError = GetLastError();
188 if (dwLastError == ERROR_BROKEN_PIPE)
189 {
190 // The other end of the pipe has been closed.
191 return ERROR_BROKEN_PIPE;
192 }
193 else
194 {
195 // An unexpected error.
196 FATAL("GetOverlappedResult failed\n");
197 }
198 }
199 else
200 {
201 // This may be WAIT_TIMEOUT or an unexpected error.
202 return dwWaitResult;
203 }
204 }
205 else
206 {
207 // This may be ERROR_BROKEN_PIPE or an unexpected error.
208 return dwLastError;
209 }
210}
ERROR_IO_PENDING
#define ERROR_IO_PENDING
Definition: dderror.h:15
ERROR_SUCCESS
#define ERROR_SUCCESS
Definition: deptool.c:10
FALSE
#define FALSE
Definition: types.h:117
ReadFile
#define ReadFile(a, b, c, d, e)
Definition: compat.h:742
GetOverlappedResult
BOOL WINAPI GetOverlappedResult(IN HANDLE hFile, IN LPOVERLAPPED lpOverlapped, OUT LPDWORD lpNumberOfBytesTransferred, IN BOOL bWait)
Definition: iocompl.c:221
WaitForSingleObject
DWORD WINAPI WaitForSingleObject(IN HANDLE hHandle, IN DWORD dwMilliseconds)
Definition: synch.c:82
GetLastError
DWORD WINAPI GetLastError(void)
Definition: except.c:1042
WAIT_OBJECT_0
#define WAIT_OBJECT_0
Definition: winbase.h:383
ERROR_BROKEN_PIPE
#define ERROR_BROKEN_PIPE
Definition: winerror.h:305

◆ Write()

bool CPipe::Write ( LPCVOID  Buffer,
DWORD  NumberOfBytesToWrite,
PDWORD  NumberOfBytesWritten 
)

Writes data to the write pipe.

This function must not be called after CloseWritePipe.

Parameters
BufferBuffer containing the data to write.
NumberOfBytesToWriteThe number of bytes to write to the pipe from Buffer.
NumberOfBytesWrittenOn return, the number of bytes actually written to the pipe.
Returns
True on success, false on failure; call GetLastError for error information.
See also
WriteFile

Definition at line 232 of file CPipe.cpp.

233{
234 if (!m_hWritePipe)
235 FATAL("Trying to write to a closed write pipe\n");
236
237 return WriteFile(m_hWritePipe, Buffer, NumberOfBytesToWrite, NumberOfBytesWritten, NULL);
238}
WriteFile
BOOL WINAPI WriteFile(IN HANDLE hFile, IN LPCVOID lpBuffer, IN DWORD nNumberOfBytesToWrite OPTIONAL, OUT LPDWORD lpNumberOfBytesWritten, IN LPOVERLAPPED lpOverlapped OPTIONAL)
Definition: rw.c:24

Friends And Related Function Documentation

◆ CPipedProcess

friend class CPipedProcess
friend

Definition at line 29 of file CPipe.h.

Member Data Documentation

◆ m_hReadPipe

HANDLE CPipe::m_hReadPipe
private

Definition at line 15 of file CPipe.h.

Referenced by CloseReadPipe(), CPipe(), Peek(), Read(), and ~CPipe().

◆ m_hWritePipe

HANDLE CPipe::m_hWritePipe
private

Definition at line 16 of file CPipe.h.

Referenced by CloseWritePipe(), CPipe(), Write(), and ~CPipe().

◆ m_lPipeCount

LONG CPipe::m_lPipeCount = 0
staticprivate

Definition at line 12 of file CPipe.h.

Referenced by CPipe().

◆ m_ReadOverlapped

OVERLAPPED CPipe::m_ReadOverlapped
private

Definition at line 14 of file CPipe.h.

Referenced by CPipe(), and Read().

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