/* 
 * fcgiapp.h --
 *
 *      Definitions for FastCGI application server programs
 *
 *
 * Copyright (c) 1996 Open Market, Inc.
 *
 * See the file "LICENSE.TERMS" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * $Id: fcgiapp.h,v 1.2 1997/05/26 22:23:22 grubba Exp $
 */

#ifndef _FCGIAPP_H
#define _FCGIAPP_H

#ifndef TCL_LIBRARY	/* Hack to see if we are building TCL since TCL
			 * needs varargs not stdarg
			 */
#include <stdarg.h>
#else
#include <varargs.h>
#endif /* TCL_LIBARARY */
#include "fcgi_config.h"

#if defined (c_plusplus) || defined (__cplusplus)
extern "C" {
#endif

/*
 * Error codes.  Assigned to avoid conflict with EOF and errno(2).
 */
#define FCGX_UNSUPPORTED_VERSION -2
#define FCGX_PROTOCOL_ERROR -3
#define FCGX_PARAMS_ERROR -4
#define FCGX_CALL_SEQ_ERROR -5

/*
 * This structure defines the state of a FastCGI stream.
 * Streams are modeled after the FILE type defined in stdio.h.
 * (We wouldn't need our own if platform vendors provided a
 * standard way to subclass theirs.)
 * The state of a stream is private and should only be accessed
 * by the procedures defined below.
 */
typedef struct FCGX_Stream {
    unsigned char *rdNext;    /* reader: first valid byte
                               * writer: equals stop */
    unsigned char *wrNext;    /* writer: first free byte
                               * reader: equals stop */
    unsigned char *stop;      /* reader: last valid byte + 1
                               * writer: last free byte + 1 */
    unsigned char *stopUnget; /* reader: first byte of current buffer
                               * fragment, for ungetc
                               * writer: undefined */
    int isReader;
    int isClosed;
    int wasFCloseCalled;
    int errorno;                /* error status */
    void (*fillBuffProc) (struct FCGX_Stream *stream);
    void (*emptyBuffProc) (struct FCGX_Stream *stream, int doClose);
    void *data;
} FCGX_Stream;

/*
 * An environment (as defined by environ(7)): A NULL-terminated array
 * of strings, each string having the form name=value.
 */
typedef char **FCGX_ParamArray;


/*
 *======================================================================
 * Control
 *======================================================================
 */

/*
 *----------------------------------------------------------------------
 *
 * FCGX_IsCGI --
 *
 *      Returns TRUE iff this process appears to be a CGI process
 *      rather than a FastCGI process.
 *
 *----------------------------------------------------------------------
 */
int FCGX_IsCGI(void);

/*
 *----------------------------------------------------------------------
 *
 * FCGX_Accept --
 *
 *      Accepts a new request from the HTTP server.
 *
 * Results:
 *	0 for successful call, -1 for error.
 *
 * Side effects:
 *
 *      Finishes the request accepted by (and frees any
 *      storage allocated by) the previous call to FCGX_Accept.
 *      Creates input, output, and error streams and
 *      assigns them to *in, *out, and *err respectively.
 *      Creates a parameters data structure to be accessed
 *      via getenv(3) (if assigned to environ) or by FCGX_GetParam
 *      and assigns it to *envp.
 *
 *      DO NOT retain pointers to the envp array or any strings
 *      contained in it (e.g. to the result of calling FCGX_GetParam),
 *      since these will be freed by the next call to FCGX_Finish
 *      or FCGX_Accept.
 *
 *----------------------------------------------------------------------
 */
int FCGX_Accept(
        FCGX_Stream **in,
        FCGX_Stream **out,
        FCGX_Stream **err,
        FCGX_ParamArray *envp);

/*
 *----------------------------------------------------------------------
 *
 * FCGX_Finish --
 *
 *      Finishes the current request from the HTTP server.
 *
 * Side effects:
 *
 *      Finishes the request accepted by (and frees any
 *      storage allocated by) the previous call to FCGX_Accept.
 *
 *      DO NOT retain pointers to the envp array or any strings
 *      contained in it (e.g. to the result of calling FCGX_GetParam),
 *      since these will be freed by the next call to FCGX_Finish
 *      or FCGX_Accept.
 *
 *----------------------------------------------------------------------
 */
void FCGX_Finish(void);

/*
 *----------------------------------------------------------------------
 *
 * FCGX_StartFilterData --
 *
 *      stream is an input stream for a FCGI_FILTER request.
 *      stream is positioned at EOF on FCGI_STDIN.
 *      Repositions stream to the start of FCGI_DATA.
 *      If the preconditions are not met (e.g. FCGI_STDIN has not
 *      been read to EOF) sets the stream error code to
 *      FCGX_CALL_SEQ_ERROR.
 *
 * Results:
 *      0 for a normal return, < 0 for error 
 *
 *----------------------------------------------------------------------
 */
int FCGX_StartFilterData(FCGX_Stream *stream);

/*
 *----------------------------------------------------------------------
 *
 * FCGX_SetExitStatus --
 *
 *      Sets the exit status for stream's request. The exit status
 *      is the status code the request would have exited with, had
 *      the request been run as a CGI program.  You can call
 *      SetExitStatus several times during a request; the last call
 *      before the request ends determines the value.
 *
 *----------------------------------------------------------------------
 */
void FCGX_SetExitStatus(int status, FCGX_Stream *stream);

/*
 *======================================================================
 * Parameters
 *======================================================================
 */

/*
 *----------------------------------------------------------------------
 *
 * FCGX_GetParam -- obtain value of FCGI parameter in environment
 *
 *
 * Results:
 *	Value bound to name, NULL if name not present in the
 *      environment envp.  Caller must not mutate the result
 *      or retain it past the end of this request.
 *
 *----------------------------------------------------------------------
 */
char *FCGX_GetParam(const char *name, FCGX_ParamArray envp);

/*
 *======================================================================
 * Readers
 *======================================================================
 */

/*
 *----------------------------------------------------------------------
 *
 * FCGX_GetChar --
 *
 *      Reads a byte from the input stream and returns it.
 *
 * Results:
 *	The byte, or EOF (-1) if the end of input has been reached.
 *
 *----------------------------------------------------------------------
 */
int FCGX_GetChar(FCGX_Stream *stream);

/*
 *----------------------------------------------------------------------
 *
 * FCGX_UnGetChar --
 *
 *      Pushes back the character c onto the input stream.  One
 *      character of pushback is guaranteed once a character
 *      has been read.  No pushback is possible for EOF.
 *
 * Results:
 *	Returns c if the pushback succeeded, EOF if not.
 *
 *----------------------------------------------------------------------
 */
int FCGX_UnGetChar(int c, FCGX_Stream *stream);

/*
 *----------------------------------------------------------------------
 *
 * FCGX_GetStr --
 *
 *      Reads up to n consecutive bytes from the input stream
 *      into the character array str.  Performs no interpretation
 *      of the input bytes.
 *
 * Results:
 *	Number of bytes read.  If result is smaller than n,
 *      the end of input has been reached.
 *
 *----------------------------------------------------------------------
 */
int FCGX_GetStr(char *str, int n, FCGX_Stream *stream);

/*
 *----------------------------------------------------------------------
 *
 * FCGX_GetLine --
 *
 *      Reads up to n-1 consecutive bytes from the input stream
 *      into the character array str.  Stops before n-1 bytes
 *      have been read if '\n' or EOF is read.  The terminating '\n'
 *      is copied to str.  After copying the last byte into str,
 *      stores a '\0' terminator.
 *
 * Results:
 *	NULL if EOF is the first thing read from the input stream,
 *      str otherwise.
 *
 *----------------------------------------------------------------------
 */
char *FCGX_GetLine(char *str, int n, FCGX_Stream *stream);

/*
 *----------------------------------------------------------------------
 *
 * FCGX_HasSeenEOF --
 *
 *      Returns EOF if end-of-file has been detected while reading
 *      from stream; otherwise returns 0.
 *
 *      Note that FCGX_HasSeenEOF(s) may return 0, yet an immediately
 *      following FCGX_GetChar(s) may return EOF.  This function, like
 *      the standard C stdio function feof, does not provide the
 *      ability to peek ahead.
 *
 * Results:
 *	EOF if end-of-file has been detected, 0 if not.
 *
 *----------------------------------------------------------------------
 */

int FCGX_HasSeenEOF(FCGX_Stream *stream);

/*
 *======================================================================
 * Writers
 *======================================================================
 */

/*
 *----------------------------------------------------------------------
 *
 * FCGX_PutChar --
 *
 *      Writes a byte to the output stream.
 *
 * Results:
 *	The byte, or EOF (-1) if an error occurred.
 * 
 *----------------------------------------------------------------------
 */
int FCGX_PutChar(int c, FCGX_Stream *stream);

/*
 *----------------------------------------------------------------------
 *
 * FCGX_PutStr --
 *
 *      Writes n consecutive bytes from the character array str
 *      into the output stream.  Performs no interpretation
 *      of the output bytes.
 *
 * Results:
 *      Number of bytes written (n) for normal return,
 *      EOF (-1) if an error occurred.
 * 
 *----------------------------------------------------------------------
 */
int FCGX_PutStr(const char *str, int n, FCGX_Stream *stream);

/*
 *----------------------------------------------------------------------
 *
 * FCGX_PutS --
 *
 *      Writes a null-terminated character string to the output stream.
 *
 * Results:
 *      number of bytes written for normal return,
 *      EOF (-1) if an error occurred.
 * 
 *----------------------------------------------------------------------
 */
int FCGX_PutS(const char *str, FCGX_Stream *stream);

/*
 *----------------------------------------------------------------------
 *
 * FCGX_FPrintF, FCGX_VFPrintF --
 *
 *      Performs printf-style output formatting and writes the results
 *      to the output stream.
 *
 * Results:
 *      number of bytes written for normal return,
 *      EOF (-1) if an error occurred.
 * 
 *----------------------------------------------------------------------
 */
int FCGX_FPrintF(FCGX_Stream *stream, const char *format, ...);

int FCGX_VFPrintF(FCGX_Stream *stream, const char *format, va_list arg);

/*
 *----------------------------------------------------------------------
 *
 * FCGX_FFlush --
 *
 *      Flushes any buffered output.
 *
 *      Server-push is a legitimate application of FCGX_FFlush.
 *      Otherwise, FCGX_FFlush is not very useful, since FCGX_Accept
 *      does it implicitly.  Calling FCGX_FFlush in non-push applications
 *      results in extra writes and therefore reduces performance.
 *
 * Results:
 *      EOF (-1) if an error occurred.
 * 
 *----------------------------------------------------------------------
 */
int FCGX_FFlush(FCGX_Stream *stream);

/*
 *======================================================================
 * Both Readers and Writers
 *======================================================================
 */

/*
 *----------------------------------------------------------------------
 *
 * FCGX_FClose --
 *
 *      Closes the stream.  For writers, flushes any buffered
 *      output.
 *
 *      Close is not a very useful operation since FCGX_Accept
 *      does it implicitly.  Closing the out stream before the
 *      err stream results in an extra write if there's nothing
 *      in the err stream, and therefore reduces performance.
 *
 * Results:
 *      EOF (-1) if an error occurred.
 * 
 *----------------------------------------------------------------------
 */
int FCGX_FClose(FCGX_Stream *stream);

/*
 *----------------------------------------------------------------------
 *
 * FCGX_GetError --
 *
 *      Return the stream error code.  0 means no error, > 0
 *      is an errno(2) error, < 0 is an FastCGI error.
 *
 *----------------------------------------------------------------------
 */
int FCGX_GetError(FCGX_Stream *stream);

/*
 *----------------------------------------------------------------------
 *
 * FCGX_ClearError --
 *
 *      Clear the stream error code and end-of-file indication.
 *
 *----------------------------------------------------------------------
 */
void FCGX_ClearError(FCGX_Stream *stream);


#if defined (__cplusplus) || defined (c_plusplus)
} /* terminate extern "C" { */
#endif

#endif	/* _FCGIAPP_H */
