Define Alias M.Z.

SCinter.c

@@ -35,6 +35,8 @@
   IS PROVIDED ON AN "AS IS" BASIS, AND THE AUTHORS AND DISTRIBUTORS HAVE
   NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR
   MODIFICATIONS.
+
+  M. Zolliker, Sept 2000, introduced formal aliases, modifications marked M.Z  
 ---------------------------------------------------------------------------*/
 #include <stdio.h>
 #include <stdlib.h>
@@ -51,6 +53,8 @@
 #include "devexec.h"
 #include "servlog.h"
 #include "macro.h"
+/* M.Z. */
+#include "definealias.h"
 
 #define MAXLEN 256
 #define MAXPAR 100
@@ -68,6 +72,7 @@
      	return NULL;
      }
      pInter->pCList = NULL;
+     pInter->AList.pFirst = NULL; /* M.Z. */
      pInter->pTcl = (void *)MacroInit(pInter);
      if(!pInter->pTcl)
      {
@@ -91,6 +96,7 @@
     
     strcpy(pBueffel,pName);
     strtolower(pBueffel);
+    RemoveAlias(&pInterp->AList,pBueffel); /* M.Z. */
     if(FindCommand(pInterp,pBueffel) != NULL)
     {
       return 0;
@@ -276,7 +282,7 @@ extern char *SkipSpace(char *pPtr);
   CommandList *FindCommand(SicsInterp *self, char *pName)
   {
     CommandList *pCurrent = NULL;
-    char pBueffel[256];    
+    char pBueffel[256], *pCmd;
 
     assert(self);
     
@@ -287,12 +293,15 @@ extern char *SkipSpace(char *pPtr);
     
     strcpy(pBueffel,pName);
     strtolower(pBueffel);
+
+    pCmd=TranslateAlias(&self->AList, pBueffel); /* M.Z. */
+
     pCurrent = self->pCList;
     while(pCurrent)
     {
       if(pCurrent->pName != NULL)
       {
-        if(strcmp(pCurrent->pName, pBueffel) == 0 )
+        if(strcmp(pCurrent->pName, pCmd) == 0 ) /* M.Z. */
         {
           return pCurrent;
         }
@@ -371,6 +380,8 @@ extern char *SkipSpace(char *pPtr);
        pCurrent = pTemp;
      }
 
+     FreeAliasList(&self->AList); /* M.Z. */
+
      /* clear Tcl_Interpreter. Must be AFTER deleting command list because
         some devices may have Tcl drivers which need to be accessed for
         proper closing of devices. 
@@ -512,3 +523,4 @@ extern char *SkipSpace(char *pPtr);
     }   
     return NULL;
   }
+

SCinter.h

@@ -10,6 +10,8 @@
 #ifndef SICSINTERPRETER
 #define SICSINTERPRETER
 #include "Scommon.h" 
+/* M.Z. */
+#include "definealias.i"
 
 typedef struct __SConnection *pSConnection;
 typedef struct __SINTER      *pSicsInterp;
@@ -35,6 +37,7 @@ typedef struct __SINTER
                OutCode eOut;
                void  *pTcl;
                int iDeleting;
+               AliasList AList; /* M.Z. */
              }SicsInterp;
              
 /*-------------------------------------------------------------------------*/
@@ -128,5 +131,6 @@ typedef struct __SINTER
   to the commands data structure is retuned. Else NULL
 */
   void *FindCommandData(SicsInterp *pSics, char *name, char *comclass);    
+
 #endif
 

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;
+  }
+

definealias.h

@@ -0,0 +1,93 @@
+/*--------------------------------------------------------------------------
+
+        D E F I N E A L I A S E S . C
+	
+	Markus Zolliker, September 2000
+	
+	copyright: see implementation file
+
+	More general and safe Aliases:
+
+        - an alias may be defined even if the corresponding command
+          does not yet exist
+
+        - SICS does not crash when the original command of an alias is
+          removed
+
+---------------------------------------------------------------------------*/
+#ifndef DEFINE_ALIAS
+#define DEFINE_ALIAS
+#include "conman.h" 
+#include "definealias.i"
+
+/*---------------------------------------------------------------------------*/
+  char *TranslateAlias(AliasList *pAList, char *pCmd);
+  /*
+    translate the command *pCmd
+    - the translation may go through several steps
+    - if no translation is found, the return value is equal to pCmd
+    - no strings are copied
+    - the return value becomes invalid when the corresponding alias is removed
+    - *pCmd must be lowercase
+  */  
+
+/*---------------------------------------------------------------------------*/
+  int RemoveAlias(AliasList *pAList, char *pCmd);
+  /*
+    remove the alias *pCmd
+    - returns 1 when the alias existed, 0 otherwise
+    - *pCmd must be lowercase
+  */
+
+/*---------------------------------------------------------------------------*/
+  void FreeAliasList(AliasList *pAList);
+  /*
+    dispose the alias list
+  */
+
+/*---------------------------------------------------------------------------*/
+  char *CreateAlias(AliasList *pAList, char *pName, char *pTranslation);
+
+  /*
+    create a new alias *pName with the translation *pTranslation
+
+    - the alias *pName must not yet exist
+    - *pTranslation is translated first
+    - recursive definitions are prohibited
+    - *pName and *pTranslation must be lowercase
+
+    if the creation is successful, the return value is NULL, otherwise
+    it points to one of the following error messages:
+
+      "recursive alias not allowed"
+      "alias already exists"
+      "not enough memory to create an alias"
+
+  */
+
+/*---------------------------------------------------------------------------*/
+  int DefineAlias(SConnection *pCon, SicsInterp *pSics, void *pData,
+                int argc, char *argv[]);
+
+  /* this command requires manager privileges
+
+    argv[1]: the alias to define
+      - must not be a proper SICS command
+      - if an alias with this name exists already, it is removed first
+
+    argv[2]: the original command
+      - if omitted, the alias is removed
+      - if it is an alias the definiton refers to it's translation
+      - may be an unknown command (probably defined later)
+
+    - AddCommand removes an eventual alias matching the command name
+
+    - RemoveCommand does not remove it's aliases
+      Trying to use an alias of a removed command leads to the error message
+      "object > ... < NOT found"
+
+    - trying to define a recursive alias leads the error message
+      "recursive alias not allowed"
+  */
+
+#endif

definealias.i

@@ -0,0 +1,20 @@
+/*--------------------------------------------------------------------------
+
+	AliasList datastructure
+	
+	Markus Zolliker, September 2000
+	
+	copyright: see implementation file
+
+---------------------------------------------------------------------------*/
+#ifndef DEFINE_ALIAS_I
+#define DEFINE_ALIAS_I
+
+typedef struct {
+    void *pFirst;
+  } AliasList;
+
+  /*
+    initialize pFirst to NULL to create an empty list
+  */
+#endif

ofac.c

@@ -248,6 +248,7 @@
     AddCommand(pInter,"MakeRuenBuffer",InitBufferSys,NULL,NULL);
     AddCommand(pInter,"MakeO2T",CreateO2T,NULL,NULL);
     AddCommand(pInter,"SicsAlias",SicsAlias,NULL,NULL);
+    AddCommand(pInter,"DefineAlias",DefineAlias,NULL,NULL); /* M.Z. */
     AddCommand(pInter,"InitDMC",InitDmc,NULL,NULL);
     AddCommand(pInter,"InitSANS",InitSANS,NULL,NULL);
     AddCommand(pInter,"MakeHM",MakeHistMemory,NULL,NULL);