// PipeProcess.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include "windows.h"
#include <iostream>
#include <stdio.h>
#define STDIN_PIPE_ERR 1
#define STDOUT_PIPE_ERR 2
#define PROCESS_CREATION_ERR 4
#define HANDLE_CLOSE_ERR 8
#define WRITE_ERROR 16
#define READ_ERROR 32
#define BUFFER_FILLED_ERR 64
#define UNKNOWN_ERR 128
enum ERR_CODE
{
};
class Pipe{
private:
	enum ERR_CODE x;
	HANDLE hChildStdinRd, hChildStdoutRd,
		   hChildStdinWr, hChildStdoutWr;
	SECURITY_ATTRIBUTES saStdio;
	PROCESS_INFORMATION pi;
	STARTUPINFO si;
	DWORD ERR_CODES;
	public:
	Pipe(CHAR* path);
	~Pipe();
	//friend ostream& operator<<(Pipe &p, LPSTR wrBuffer);
	//friend istream& operator>>(Pipe &p, LPSTR &rdBuffer);
	void WriteToPipe(LPSTR wrBuffer, DWORD bytesToWrite);
	void ReadFromPipe(LPSTR rdBuffer);
protected:
};
Pipe::Pipe()
{
	ERR_CODES = 0;
#pragma region Process Creation
	//fill memory with 0's to prevent random errors
	ZeroMemory(&pi , sizeof(PROCESS_INFORMATION));
	ZeroMemory(&si , sizeof(STARTUPINFO));
	//Standard startup settings
	si.cb = sizeof(STARTUPINFO);
	si.hStdError = hChildStdoutWr;
	si.hStdOutput = hChildStdoutWr;
	si.hStdInput = hChildStdinRd;
	si.dwFlags |= STARTF_USESTDHANDLES;
	//Create the process and log any errors if any occur
	ERR_CODES |= ~(CreateProcess(NULL,
		"child",
		NULL,
		NULL,
		TRUE,
		0,
		NULL,
		NULL,
		&si,
		&pi)) * PROCESS_CREATION_ERR ;
#pragma endregion Process Creation
#pragma region Pipe Creation
	//Security settings
	saStdio.nLength = sizeof(SECURITY_ATTRIBUTES);
	saStdio.lpSecurityDescriptor = NULL;
	saStdio.bInheritHandle = TRUE;
	
	//Pipe creation and error logging
	ERR_CODES |= (~(CreatePipe(&hChildStdinRd, &hChildStdinWr, &saStdio, 0)) * STDIN_PIPE_ERR) | 
				 (~(CreatePipe(&hChildStdoutRd, &hChildStdoutWr, &saStdio, 0)) * STDOUT_PIPE_ERR);
	//Handle settings, inheritance
	SetHandleInformation(hChildStdoutRd, HANDLE_FLAG_INHERIT, 0);
	SetHandleInformation(hChildStdinWr, HANDLE_FLAG_INHERIT, 0);
#pragma endregion Pipe Creation
}
Pipe::~Pipe()
{
	ERR_CODES |= ~(CloseHandle(pi.hProcess) &&
				   CloseHandle(pi.hThread) && 
				   CloseHandle(hChildStdinRd) && 
				   CloseHandle(hChildStdinWr) && 
				   CloseHandle(hChildStdoutRd) && 
				   CloseHandle(hChildStdoutWr)) * HANDLE_CLOSE_ERR;
	if (ERR_CODES!=0)
		printf("Error code: %d",ERR_CODES);
}
//ostream& Pipe::operator<<(Pipe &p, LPSTR wrBuffer)
//{
//	DWORD bytesWritten, bytesToWrite=sizeof(string);
//	if(bytesToWrite==0)
//		return p;
//	ERR_CODES |= (~(WriteFile(hChildStdinWr, wrBuffer, bytesToWrite, &bytesWritten, NULL)) * ERR_CODE.WRITE_ERROR);
//	if (bytesWritten == 0)
//		return p;
//	if (bytesWritten < bytesToWrite)
//		return p<<wrBuffer[bytesWritten];
//}
//
//istream& Pipe::operator>>(Pipe &p, LPSTR &rdBuffer)
//{
//	DWORD bytesRead, bytesToRead = sizeof(rdBuffer);
//	if (bytesToRead == 0)
//	{
//		ERR_CODES |= ERR_CODE.BUFFER_FILLED_ERR;
//		return p;
//	}
//	ERR_CODES |= (~(ReadFile(hChildStdoutRd, &rdBuffer, bytesToRead, &bytesRead, NULL)) * ERR_CODE.READ_ERROR);
//	if (bytesRead == 0)
//		return p;
//	if (bytesRead == bytesToRead)
//	{
//		ERR_CODES |= ERR_CODE.BUFFER_FILLED_ERR;
//		return p;
//	}
//}
void Pipe::WriteToPipe(LPSTR wrBuffer, DWORD bytesToWrite)
{
	DWORD bytesWritten;
	if(bytesToWrite==0)
		return;
	ERR_CODES |= (~(WriteFile(hChildStdinWr, wrBuffer, bytesToWrite, &bytesWritten, NULL)) * WRITE_ERROR);
	if (bytesWritten == 0)
		return;
	if (bytesWritten < bytesToWrite)
		WriteToPipe(&wrBuffer[bytesWritten], bytesToWrite - bytesWritten);
}
void Pipe::ReadFromPipe(LPSTR rdBuffer)
{
	DWORD bytesRead, bytesToRead = sizeof(rdBuffer);
	if (bytesToRead == 0)
	{
		ERR_CODES |= BUFFER_FILLED_ERR;
		return;
	}
	ERR_CODES |= (~(ReadFile(hChildStdoutRd, &rdBuffer, bytesToRead, &bytesRead, NULL)) * READ_ERROR);
	if (bytesRead == 0)
		return;
	if (bytesRead == bytesToRead)
	{
		ERR_CODES |= BUFFER_FILLED_ERR;
		return;
	}
}