Define Alias M.Z.

definealias.c

@@ -0,0 +1,217 @@
+/*---------------------------------------------------------------------------
+
+  One more approach for the implementation of Aliases
+
+
+
+  Markus Zolliker, September 2000
+
+  Copyright:
+
+  Labor fuer Neutronenstreuung
+  Paul Scherrer Institut
+  CH-5423 Villigen-PSI
+
+
+  The authors hereby grant permission to use, copy, modify, distribute,
+  and license this software and its documentation for any purpose, provided
+  that existing copyright notices are retained in all copies and that this
+  notice is included verbatim in any distributions. No written agreement,
+  license, or royalty fee is required for any of the authorized uses.
+  Modifications to this software may be copyrighted by their authors
+  and need not follow the licensing terms described here, provided that
+  the new terms are clearly indicated on the first page of each file where
+  they apply.
+
+  IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY
+  FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+  ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY
+  DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE
+  POSSIBILITY OF SUCH DAMAGE.
+
+  THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
+  INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.  THIS SOFTWARE
+  IS PROVIDED ON AN "AS IS" BASIS, AND THE AUTHORS AND DISTRIBUTORS HAVE
+  NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR
+  MODIFICATIONS.
+---------------------------------------------------------------------------*/
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <string.h>
+#include "fortify.h"
+#include "definealias.h"
+
+typedef struct __Aitem {
+                          struct __Aitem *pNext;
+                          char       *pName;
+                          char       *pCmd;
+                        }  AliasItem;
+
+/*------------------------------------------------------------------------*/
+  char *TranslateAlias(AliasList *pAList, char *pCmd) 
+  {
+    AliasItem *pAlias;
+
+    assert(pAList!=NULL && pCmd!=NULL);
+
+    pAlias=pAList->pFirst;
+    while (pAlias!=NULL)
+    {
+      if (0 == strcmp(pAlias->pName, pCmd))
+      {
+        pCmd = pAlias->pCmd; /* note that there may be cascaded translations */
+      }
+      pAlias = pAlias->pNext;
+    }
+    return(pCmd);
+  }
+/*------------------------------------------------------------------------*/
+  int RemoveAlias(AliasList *pAList, char *pCmd) 
+  {
+    AliasItem *pAlias = NULL, *pPrev = NULL;
+
+    assert(pAList!=NULL && pCmd!=NULL);
+
+    pPrev=(AliasItem *)pAList;
+    pAlias=pAList->pFirst;
+    while (pAlias != NULL && 0 != strcmp(pAlias->pName, pCmd))
+    {
+      pPrev = pAlias;
+      pAlias = pAlias->pNext;
+    }
+    if (pAlias==NULL)
+    {
+      return 0; /* not found */
+    }
+
+    /* remove it */
+    pPrev->pNext = pAlias->pNext;
+    free(pAlias->pName);
+    free(pAlias->pCmd);
+    free(pAlias);
+    return(1);
+  }
+/*------------------------------------------------------------------------*/
+  void FreeAliasList(AliasList *pAList)
+  {
+    AliasItem *pAlias = NULL, *pNext = NULL;
+
+    assert(pAList!=NULL);
+
+    pAlias=pAList->pFirst;
+    while (pAlias != NULL)
+    {
+      pNext=pAlias->pNext;
+      free(pAlias->pName);
+      free(pAlias->pCmd);
+      free(pAlias);
+      pAlias = pNext;
+    }
+  }
+/*------------------------------------------------------------------------*/
+  char *CreateAlias(AliasList *pAList, char *pName, char *pTranslation)  
+  { /* arguments must be lower case */
+    AliasItem *pAlias = NULL, *pNew = NULL, *pTail = NULL;
+    char *pCmd;
+
+    /* translate 2nd argument */
+    pCmd=TranslateAlias(pAList, pTranslation);
+    if (0==strcmp(pName, pCmd)) /* translation matches */
+    {
+      return "recursive alias not allowed";
+    }
+
+    /* find last element pTail and check that alias does not yet exist */
+    pTail = (AliasItem *)pAList;
+    pAlias = pAList->pFirst;
+    while (pAlias!=NULL)
+    {
+      pTail=pAlias;
+      if (0 == strcmp(pAlias->pName, pName))
+      {
+        return "alias already exists";
+      }
+      pAlias = pAlias->pNext;
+    }
+
+    /* allocate the list entry */
+    pNew = malloc(sizeof(AliasItem));
+    if (pNew!=NULL)
+    {
+      pNew->pNext = NULL;
+      pNew->pName = strdup(pName);
+      if (pNew->pName!=NULL)
+      {
+        pNew->pCmd  = strdup(pCmd);
+        if (pNew->pCmd!=NULL)
+        {
+          /* insert at tail */
+          pTail->pNext = pNew;
+          return NULL; /* o.k. */
+        }
+      }
+    }
+    return "not enough memory to create an alias";
+
+  }
+
+/*------------------------------------------------------------------------*/
+  int DefineAlias(pSConnection pCon, SicsInterp *pSics, void *pData,
+                int argc, char *argv[]) 
+  {
+    char pBueffel[256];
+    int iRet;
+    CommandList *pCom = NULL;
+    char *pErr;
+
+    if(!SCMatchRights(pCon,usMugger))
+    {
+       SCWrite(pCon,"ERROR: only managers may define aliases",
+               eError);
+       return 0;
+    }
+
+    argtolower(argc,argv);
+
+    if(argc == 2) /* remove case */
+    {
+      iRet=RemoveAlias(&pSics->AList, argv[1]);
+      if (iRet==0)
+      {
+        SCWrite(pCon,"ERROR: alias not found",
+                eError);
+        return 0;
+      }
+      return 1;
+    }
+    if(argc != 3)
+    {
+      SCWrite(pCon,"ERROR: illegal number of arguments to DefineAlias",
+              eError);
+      return 0;
+    }
+
+    pCom = FindCommand(pSics, argv[1]);
+    if (pCom!=NULL)
+    {
+      SCWrite(pCon,"ERROR: an alias must not overwrite a command",
+              eError);
+      return 0;
+    }
+
+    /* remove the old alias, if any */
+    RemoveAlias(&pSics->AList, argv[1]);
+
+    pErr=CreateAlias(&pSics->AList, argv[1], argv[2]);
+    if (pErr!=NULL)
+    {
+      sprintf(pBueffel,"ERROR: %s", pErr);
+      SCWrite(pCon,pBueffel,eError);
+      return 0;
+    }
+
+    return 1;
+  }
+