Тестовые примеры / ch8 / shell

	/* This is the shell.h header file, which declares the CMD_INFO class */

	#ifndef SHELL_H

	#define SHELL_H



	#include <iostream.h>

	#include <string.h>

	#include <assert.h>

	#include <malloc.h>


	/* check IO redirection and command pipe conflict */

	#define CHECK_IO(fn) if (fn) { \
			cerr << "Invalid re-direct: " << fn << endl; delete fn; fn = 0; }



	class CMD_INFO 

	{

 		public:

 			char** 					argv;				// command and argument list

			char* 					infile;				// std input re-directed file

 			char* 					outfile;				// std. output re-directed file

 			int 					backgrnd;				// 1 if cmd to run in backgrnd

 			CMD_INFO*					pSubcmd;				// cmds to be run in a sub-shell

 			CMD_INFO*					Pipe;				// next command after `|'

 			CMD_INFO*					Next;				// next command after `;'



 			// Constructor function

		 	CMD_INFO() 

			{ 

 				argv = 0;

			 	infile = outfile = 0;

 				backgrnd = 0;

 				pSubcmd = Pipe = Next = 0;

 			};



 			// Destructor function

 			~CMD_INFO() 

			{ 

 				if (infile) delete infile;

 				if (outfile) delete outfile;

 				for (int i=0; argv && argv[i]; i++) delete argv[i];

 				delete argv;

 			};



			// Add one argument string to argv list

 			void add_arg( char* str )

			{ 

 				int 	len = 1;

 				if (!argv)

	 				argv = (char**)malloc(sizeof(char*)*2);

 				else 

				{

 					while (argv[len]) len++; 

 					len++;

 					argv = (char**)realloc(argv,sizeof(char*)*(len+1));

			 	}

 				assert(argv[len-1] = strdup(str)); 

 				argv[len] = 0;

 			};



			// Add a standard input or output redirect file name

 			void add_iofile( char*& iofile, char* fnm ) 	

			{	 

			 	if (iofile) 

 					cerr << "Multiple in-direct: " << iofile << " vs " << fnm << endl;

			 	else iofile = fnm;

 			}; 



		 	// Add a command pipe

 			void add_pipe ( CMD_INFO* pCmd )

			{ 

 				if (Pipe) 

 					Pipe->add_pipe(pCmd);

 				else {

 					CHECK_IO(outfile);

 					CHECK_IO(pCmd->infile);

				 	Pipe = pCmd;

 				}

 			};



 			// Add a next command stage

 			void add_next( CMD_INFO* pCmd )

			{ 

 				if (Next)

 					Next->add_next(pCmd);

 				else Next = pCmd;

 			};

	};


	extern void exec_cmd( CMD_INFO *pCmd );
	extern "C" int yyparse();


	#endif