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#include "out2con.h"
#include <windows.h>
#include <stdio.h>
#include <io.h>
class ConsoleEcho
{
public:
ConsoleEcho();
~ConsoleEcho();
private:
DWORD ThreadLoop();
static DWORD WINAPI ThreadFunc(void* param);
FILE m_originalStdout;
int m_stdoutfd;
int m_pipefd;
HANDLE m_hReadPipe, m_hWritePipe;
HANDLE m_hThread;
static const int BUFSIZE=512;
};
ConsoleEcho *
CreateConsoleEcho()
{
return new ConsoleEcho;
}
void
DestroyConsoleEcho(ConsoleEcho *echo)
{
delete echo;
}
DWORD WINAPI ConsoleEcho::ThreadFunc(void* param)
{
return ((ConsoleEcho*)(param))->ThreadLoop();
}
DWORD ConsoleEcho::ThreadLoop()
{
DWORD dwRead, dwWritten;
CHAR chBuf[BUFSIZE];
BOOL bSuccess = FALSE;
// Note that the following does not work when running in the msvc2010
// debugger with redirected output; you still get the redirected file
// handle, not the console:
//HANDLE hConsoleStdOut = GetStdHandle(STD_OUTPUT_HANDLE);
// This seems to be more reliable:
HANDLE hConsoleStdOut = CreateFile("CONOUT$",
GENERIC_WRITE,
FILE_SHARE_WRITE,
NULL, OPEN_EXISTING, 0, 0);
for (;;) {
// read from redirected stdout
bSuccess = ReadFile(m_hReadPipe, chBuf, BUFSIZE, &dwRead, NULL);
if (!bSuccess || (dwRead == 0))
break;
// write to console
WriteFile(hConsoleStdOut, chBuf, dwRead, &dwWritten, NULL);
// also write to original stdout
if (m_stdoutfd>=0) {
_write(m_stdoutfd, chBuf, dwRead);
// _commit() causes assert if m_stdoutfd is a device (e.g., console or NUL).
if (!_isatty(m_stdoutfd))
_commit(m_stdoutfd);
}
}
CloseHandle(hConsoleStdOut);
return 0;
}
ConsoleEcho::ConsoleEcho()
{
// setup console
AllocConsole();
// create pipe
CreatePipe(&m_hReadPipe, &m_hWritePipe, NULL, 0);
// save original stdout to preserve commandline-specified redirection
m_stdoutfd = _fileno(stdout);
// and copy the whole damn FILE structure so we can restore it
// when we're done. I don't know any other way to restore the
// crazy windows gui default '-2' filedesc stdout.
m_originalStdout = *stdout;
// hook up the write end of our pipe to stdout
m_pipefd = _open_osfhandle((intptr_t)m_hWritePipe, 0);
// take our os file handle and allocate a crt FILE for it
FILE* fp = _fdopen(m_pipefd, "w");
// copy to stdout
*stdout = *fp;
// now slam the allocated FILE's _flag to zero to mark it as free without
// actually closing the os file handle and pipe
fp->_flag = 0;
// disable buffering
setvbuf(stdout, NULL, _IONBF, 0);
// Create a thread to process our pipe, forwarding output
// to both the console and the original stdout
m_hThread = CreateThread(NULL, 0, &ThreadFunc, this, 0, NULL);
}
ConsoleEcho::~ConsoleEcho()
{
// fclose() unfortunately immediately invalidates the read pipe before the
// pipe thread has a chance to flush it, so don't do that.
//fclose(stdout);
// instead, just slam the original stdout
*stdout = m_originalStdout;
//printf("Safe to printf now and no longer echoed to console.\n");
// Close write pipe
_close(m_pipefd);
// and wait here for pipe thread to exit
WaitForSingleObject(m_hThread, 1000);
// now close read pipe as well
CloseHandle(m_hReadPipe);
}
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