Initial commit.
This commit is contained in:
Jim Gray
482
tools/ModView/commarea.cpp
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482
tools/ModView/commarea.cpp
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// Filename:- CommArea.cpp
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//
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// contains low-level code for shared-memory inter-program comms
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//
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#include "stdafx.h"
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#include "includes.h"
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//#include <winbase.h>
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//
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#include "CommArea.h"
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#define sCOMMAREA_NAME "COMMAREA_MODVIEW"
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#define iCOMMAREA_VERSION 1
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typedef enum
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{
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cst_READY=0, // nothing pending
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cst_SERVERREQ, // server has request for client
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cst_CLIENTREQ, // client has request for server
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cst_CLIENTERR, // client failed a request, check PassedData.sError[]
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cst_SERVERERR, // server failed a request, check PassedData.sError[]
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cst_WAIT, // raised by either side while filling in details of stuff
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//
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// these last 2 I could probably get rid of and replace by just setting back to cst_READY, but for now...
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//
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cst_CLIENTOK, // client completed a request
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cst_SERVEROK, // server completed a request
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} CommStatus_e;
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typedef struct
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{
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// message passing... (arb. buffer sizes, can be increased if you bump the version number as well)
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//
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char sCommand[1024]; // used to pass text command (case insensitive)
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byte bData[65536]; //
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int iDataSize;
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// other...
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//
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char sError[4096]; // used for reporting problems
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} PassedData_t;
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typedef struct
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{
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// verification fields...
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//
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int iVersion; // version of this struct, should match in client and server
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int iSize; // size of this struct, belt and braces safety
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//
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// the semaphore field...
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//
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CommStatus_e eStatus;
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// message passing... (arb. buffer sizes, can be increased if you bump the version number as well)
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//
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PassedData_t PassedData;
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} CommArea_t;
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static CommArea_t CommArea_USEONLYDURINGINIT, *gpMappedCommArea = NULL;
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static HANDLE hFileMap = NULL;
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static bool bIAmServer = false;
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// special copy that I can put all recieved data into so that the acknowledging a message doesn't let the other
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// app zap the results with a new message while you're busy copying the data elsewhere...
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//
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static PassedData_t LocalData;
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// by having a common string at the front of my error strings I can allow the caller to detect
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// whether they're messages produced by me or by Windows (and allow for stripping the common piece if desired)
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//
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#define sERROR_COMMAREAUNINITIALISED "CommArea: function called while comms not initialised, or init failed"
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#define sERROR_COMMANDSTRINGTOOLONG "CommArea: command string too long"
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#define sERROR_COMMANDDATATOOLONG "CommArea: command data too long"
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#define sERROR_BADCOMMANDACKTIME "CommArea: command acknowledge called but no command was pending"
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#define sERROR_BADCOMMANDCLEARTIME "CommArea: command-clear called while no error or ack pending - commands lost?"
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#define sERROR_NOTASKPENDING "CommArea: error report attempted while task not pending"
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#define sERROR_BUSY "CommArea: busy"
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static PassedData_t *CommArea_LocaliseData(void)
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{
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LocalData = gpMappedCommArea->PassedData;
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return &LocalData;
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}
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// buffer-size query for caller-app to setup args legally (if wanting to send big commands and unsure of space)...
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//
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int CommArea_GetMaxDataSize(void)
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{
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return sizeof(LocalData.bData);
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}
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int CommArea_GetMaxCommandStrlen(void)
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{
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return sizeof(LocalData.sCommand);
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}
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// getting this size wrong while sending error strings will never cause problems, they're just clipped
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//
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int CommArea_GetMaxErrorStrlen(void)
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{
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return sizeof(LocalData.sError);
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}
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void CommArea_ShutDown(void)
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{
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if (gpMappedCommArea)
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{
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UnmapViewOfFile( gpMappedCommArea );
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gpMappedCommArea = NULL;
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}
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if (hFileMap)
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{
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CloseHandle(hFileMap);
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hFileMap = NULL;
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}
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}
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static LPCSTR CommArea_MapViewOfFile(void)
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{
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gpMappedCommArea = (CommArea_t *) MapViewOfFile(hFileMap, // HANDLE hFileMappingObject, // file-mapping object to map into
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FILE_MAP_ALL_ACCESS,// DWORD dwDesiredAccess, // access mode
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0, // DWORD dwFileOffsetHigh, // high-order 32 bits of file offset
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0, // DWORD dwFileOffsetLow, // low-order 32 bits of file offset
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0 // DWORD dwNumberOfBytesToMap // number of bytes to map
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);
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return gpMappedCommArea ? NULL : SystemErrorString();
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}
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// return is either error message, or NULL for success...
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//
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LPCSTR CommArea_ServerInitOnceOnly(void)
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{
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LPCSTR psError = NULL;
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hFileMap = CreateFileMapping( INVALID_HANDLE_VALUE, // HANDLE hFile // handle to file to map
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NULL, // LPSECURITY_ATTRIBUTES lpFileMappingAttributes,
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PAGE_READWRITE, // DWORD flProtect, // protection for mapping object
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0, // DWORD dwMaximumSizeHigh, // high-order 32 bits of object size
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sizeof(CommArea_USEONLYDURINGINIT), // DWORD dwMaximumSizeLow, // low-order 32 bits of object size
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sCOMMAREA_NAME // LPCTSTR lpName // name of file-mapping object
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);
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DWORD dwError = GetLastError();
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if (hFileMap == NULL || dwError == ERROR_ALREADY_EXISTS)
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{
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psError = SystemErrorString(dwError);
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}
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else
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{
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// ok so far, so get a map view of it...
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//
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psError = CommArea_MapViewOfFile();
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if (!psError)
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{
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// Yeeehaaa.... let's init this baby...
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//
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ZEROMEMPTR(gpMappedCommArea);
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gpMappedCommArea->iVersion = iCOMMAREA_VERSION;
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gpMappedCommArea->iSize = sizeof(*gpMappedCommArea);
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bIAmServer = true;
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}
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}
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if (psError)
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{
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CommArea_ShutDown();
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}
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return psError;
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}
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// return is either error message, or NULL for success...
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//
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LPCSTR CommArea_ClientInitOnceOnly(void)
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{
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LPCSTR psError = NULL;
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hFileMap = OpenFileMapping( FILE_MAP_ALL_ACCESS, // DWORD dwDesiredAccess, // access mode
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true, // BOOL bInheritHandle, // inherit flag
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sCOMMAREA_NAME // LPCTSTR lpName // pointer to name of file-mapping object
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);
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if (!hFileMap)
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{
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psError = SystemErrorString();
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}
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else
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{
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// ok so far, so get a map view of it...
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//
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psError = CommArea_MapViewOfFile();
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if (!psError)
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{
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// let's give it a quick check for version differences...
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//
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static char sError[1024];
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if (gpMappedCommArea->iVersion != iCOMMAREA_VERSION)
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{
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sprintf(sError,"CommArea version # mismatch, found %d but expected %d!",gpMappedCommArea->iVersion, iCOMMAREA_VERSION);
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psError = sError;
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}
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else
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{
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if (gpMappedCommArea->iSize != sizeof(*gpMappedCommArea))
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{
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sprintf(sError,"CommArea struct size mismatch, found %d but expected %d!",gpMappedCommArea->iSize, sizeof(*gpMappedCommArea));
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psError = sError;
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}
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else
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{
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// Yeeehaaa.... everything ok...
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//
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bIAmServer = false; // unnec. but clearer
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}
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}
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}
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}
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if (psError)
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{
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CommArea_ShutDown();
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}
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return psError;
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}
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// can be safely called even when init failed...
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//
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bool CommArea_IsIdle(void)
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{
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if (!gpMappedCommArea)
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return true;
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return gpMappedCommArea->eStatus == cst_READY
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/*
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||
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gpMappedCommArea->eStatus == cst_CLIENTOK ||
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gpMappedCommArea->eStatus == cst_SERVEROK
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*/
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;
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}
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// call to query if any new commands are waiting for us, and return local (non-shared) ptrs if so.
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//
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// return = command string, else NULL for none
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//
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// This can be safely called even if the OnceOnlyInit call failed
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//
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LPCSTR CommArea_IsCommandWaiting(byte **ppbDataPassback, int *piDatasizePassback)
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{
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assert(ppbDataPassback);
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assert(piDatasizePassback);
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if (gpMappedCommArea && gpMappedCommArea->eStatus == (bIAmServer ? cst_CLIENTREQ : cst_SERVERREQ) )
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{
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// make local (non-shared) copy of the data so we can access via ptrs without next command overwriting it...
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//
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CommArea_LocaliseData();
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*ppbDataPassback = &LocalData.bData[0];
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*piDatasizePassback = LocalData.iDataSize;
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return LocalData.sCommand;
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}
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return NULL;
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}
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// call this only (and always) after you send a command to tell you when the other app has finished responding to it
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//
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// return = response string (may be blank), else NULL for none (optional data fields are filled in if supplied)
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//
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LPCSTR CommArea_IsAckWaiting(byte **ppbDataPassback /* = NULL */, int *piDatasizePassback /* = NULL */)
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{
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assert(gpMappedCommArea);
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if (gpMappedCommArea && gpMappedCommArea->eStatus == (bIAmServer ? cst_CLIENTOK : cst_SERVEROK) )
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{
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// make local (non-shared) copy of the data so we can access via ptrs without next command overwriting it...
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//
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CommArea_LocaliseData();
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if ( ppbDataPassback)
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*ppbDataPassback = &LocalData.bData[0];
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if ( piDatasizePassback)
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*piDatasizePassback = LocalData.iDataSize;
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return LocalData.sCommand;
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}
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return NULL;
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}
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// check outgoing data for size-exceeding, and copy to send buffer if everything ok...
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//
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// return = errmess or NULL for ok
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//
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static LPCSTR CommArea_SetupAndLegaliseOutgoingData(LPCSTR psCommand, byte *pbData, int iDataSize)
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{
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if (!gpMappedCommArea)
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return sERROR_COMMAREAUNINITIALISED;
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if (psCommand && strlen(psCommand) > sizeof(gpMappedCommArea->PassedData.sCommand)-1)
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return sERROR_COMMANDSTRINGTOOLONG;
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if (pbData && iDataSize > sizeof(gpMappedCommArea->PassedData.bData))
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return sERROR_COMMANDDATATOOLONG;
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// seems ok, so copy it to outgoing...
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//
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CommStatus_e ePrevStatus = gpMappedCommArea->eStatus;
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gpMappedCommArea->eStatus = cst_WAIT;
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{
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if (psCommand)
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{
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strcpy(gpMappedCommArea->PassedData.sCommand,psCommand);
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}
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else
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{
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strcpy(gpMappedCommArea->PassedData.sCommand,"");
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}
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if (pbData)
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{
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memcpy(gpMappedCommArea->PassedData.bData, pbData, iDataSize);
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}
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else
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{
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//ZEROMEM(gpMappedCommArea->PassedData.bData); // not actually necessary
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}
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gpMappedCommArea->PassedData.iDataSize = iDataSize;
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}
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gpMappedCommArea->eStatus = ePrevStatus;
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return NULL;
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}
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// you can ignore the return code from this if you only call it sensibly, ie when you know you've just completed a
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// command task
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//
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// NOTE: if there's an error then the acknowledge is NOT sent!!!!
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//
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LPCSTR CommArea_CommandAck(LPCSTR psCommand /* = NULL */, byte *pbData /* = NULL */, int iDataSize /* = 0 */)
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{
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assert(gpMappedCommArea );
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if (gpMappedCommArea && gpMappedCommArea->eStatus == (bIAmServer ? cst_CLIENTREQ : cst_SERVERREQ) )
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{
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LPCSTR psError = CommArea_SetupAndLegaliseOutgoingData(psCommand, pbData, iDataSize);
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if (psError)
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{
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assert(0);
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return psError;
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}
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gpMappedCommArea->eStatus = (bIAmServer ? cst_SERVEROK : cst_CLIENTOK);
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return NULL;
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}
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assert(0);
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return sERROR_BADCOMMANDACKTIME;
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}
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// Call this to query for any pending error messages from the other program
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//
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// return = error, else NULL for none
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//
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// This can be safely called even if the OnceOnlyInit call failed
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//
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LPCSTR CommArea_IsErrorWaiting(void)
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{
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if (gpMappedCommArea && gpMappedCommArea->eStatus == (bIAmServer ? cst_CLIENTERR : cst_SERVERERR) )
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{
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return CommArea_LocaliseData()->sError;
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}
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return NULL;
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}
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// Only call this after you've sent a command, then received either an acknowledgement or an error
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//
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// You can ignore the return error from this if you only call it sensibly, ie when you know there was an error
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// that wanted displaying...
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//
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LPCSTR CommArea_CommandClear(void)
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{
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assert(gpMappedCommArea );
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if (gpMappedCommArea &&
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(
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gpMappedCommArea->eStatus == (bIAmServer ? cst_CLIENTERR : cst_SERVERERR)
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||
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gpMappedCommArea->eStatus == (bIAmServer ? cst_CLIENTOK : cst_SERVEROK)
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)
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)
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{
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gpMappedCommArea->eStatus = cst_READY;
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return NULL;
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}
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return sERROR_BADCOMMANDCLEARTIME;
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}
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// Call to report an error, this should only be done on receipt of a command that your app had a problem obeying...
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//
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// You can ignore the return code from this if you only call it sensibly, ie when you know you're just reporting an error
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//
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// NOTE: if there's an error (like you're calling this at the wrong time) then this error is NOT sent!!!!
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//
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LPCSTR CommArea_CommandError(LPCSTR psError)
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{
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assert(gpMappedCommArea);
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if (gpMappedCommArea && gpMappedCommArea->eStatus == (bIAmServer ? cst_CLIENTREQ : cst_SERVERREQ) )
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{
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gpMappedCommArea->eStatus = cst_WAIT;
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{
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strncpy(gpMappedCommArea->PassedData.sError, psError, sizeof(gpMappedCommArea->PassedData.sError)-1);
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gpMappedCommArea->PassedData.sError[sizeof(gpMappedCommArea->PassedData.sError)-1] = '\0';
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}
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gpMappedCommArea->eStatus = (bIAmServer ? cst_SERVERERR : cst_CLIENTERR);
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return NULL;
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}
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return sERROR_NOTASKPENDING;
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}
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// return NULL = success, else error message... (pbData can be NULL if desired, ditto iDataSize)
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//
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LPCSTR CommArea_IssueCommand(LPCSTR psCommand, byte *pbData /* = NULL */, int iDataSize /* = 0 */)
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{
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if (!CommArea_IsIdle())
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return sERROR_BUSY;
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assert(gpMappedCommArea);
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if (!gpMappedCommArea)
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return sERROR_COMMAREAUNINITIALISED;
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LPCSTR psError = CommArea_SetupAndLegaliseOutgoingData(psCommand, pbData, iDataSize);
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if (psError)
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{
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assert(0);
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return psError;
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}
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gpMappedCommArea->eStatus = (bIAmServer ? cst_SERVERREQ : cst_CLIENTREQ);
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return NULL;
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}
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////////////////////// eof ////////////////
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