Fix the onecolumn method in the TCL interface so that it works the same

as the eval method in all ways except for returning just the first value
in the result set. (CVS 1944)

FossilOrigin-Name: f323e4f86a08fe6448cbd4ff7cab459e8039d9f1

1 files changed, 71 insertions, 102 deletions

diff --git a/src/tclsqlite.c b/src/tclsqlite.c
index bcc2f0ef6..e907878d0 100644
--- a/src/tclsqlite.c
+++ b/src/tclsqlite.c
@@ -11,7 +11,7 @@
 *************************************************************************
 ** A TCL Interface to SQLite
 **
-** $Id: tclsqlite.c,v 1.104 2004/09/06 17:24:13 drh Exp $
+** $Id: tclsqlite.c,v 1.105 2004/09/07 13:20:35 drh Exp $
 */
 #ifndef NO_TCL     /* Omit this whole file if TCL is unavailable */
 
@@ -74,35 +74,6 @@ struct SqliteDb {
 };
 
 /*
-** This is a second alternative callback for database queries.  A the
-** first column of the first row of the result is made the TCL result.
-*/
-static int DbEvalCallback3(
-  void *clientData,      /* An instance of CallbackData */
-  int nCol,              /* Number of columns in the result */
-  char ** azCol,         /* Data for each column */
-  char ** azN            /* Name for each column */
-){
-  Tcl_Interp *interp = (Tcl_Interp*)clientData;
-  Tcl_Obj *pElem;
-  if( azCol==0 ) return 1;
-  if( nCol==0 ) return 1;
-#ifdef UTF_TRANSLATION_NEEDED
-  {
-    Tcl_DString dCol;
-    Tcl_DStringInit(&dCol);
-    Tcl_ExternalToUtfDString(NULL, azCol[0], -1, &dCol);
-    pElem = Tcl_NewStringObj(Tcl_DStringValue(&dCol), -1);
-    Tcl_DStringFree(&dCol);
-  }
-#else
-  pElem = Tcl_NewStringObj(azCol[0], -1);
-#endif
-  Tcl_SetObjResult(interp, pElem);
-  return 1;
-}
-
-/*
 ** TCL calls this procedure when an sqlite3 database command is
 ** deleted.
 */
@@ -496,48 +467,6 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
     break;
   }
 
-  /*    $db progress ?N CALLBACK?
-  ** 
-  ** Invoke the given callback every N virtual machine opcodes while executing
-  ** queries.
-  */
-  case DB_PROGRESS: {
-    if( objc==2 ){
-      if( pDb->zProgress ){
-        Tcl_AppendResult(interp, pDb->zProgress, 0);
-      }
-    }else if( objc==4 ){
-      char *zProgress;
-      int len;
-      int N;
-      if( TCL_OK!=Tcl_GetIntFromObj(interp, objv[2], &N) ){
-	return TCL_ERROR;
-      };
-      if( pDb->zProgress ){
-        Tcl_Free(pDb->zProgress);
-      }
-      zProgress = Tcl_GetStringFromObj(objv[3], &len);
-      if( zProgress && len>0 ){
-        pDb->zProgress = Tcl_Alloc( len + 1 );
-        strcpy(pDb->zProgress, zProgress);
-      }else{
-        pDb->zProgress = 0;
-      }
-#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
-      if( pDb->zProgress ){
-        pDb->interp = interp;
-        sqlite3_progress_handler(pDb->db, N, DbProgressHandler, pDb);
-      }else{
-        sqlite3_progress_handler(pDb->db, 0, 0, 0);
-      }
-#endif
-    }else{
-      Tcl_WrongNumArgs(interp, 2, objv, "N CALLBACK");
-      return TCL_ERROR;
-    }
-    break;
-  }
-
   /*     $db changes
   **
   ** Return the number of rows that were modified, inserted, or deleted by
@@ -685,13 +614,18 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
    
   /*
   **    $db eval $sql ?array? ?{  ...code... }?
+  **    $db onecolumn $sql
   **
   ** The SQL statement in $sql is evaluated.  For each row, the values are
   ** placed in elements of the array named "array" and ...code... is executed.
   ** If "array" and "code" are omitted, then no callback is every invoked.
   ** If "array" is an empty string, then the values are placed in variables
   ** that have the same name as the fields extracted by the query.
+  **
+  ** The onecolumn method is the equivalent of:
+  **     lindex [$db eval $sql] 0
   */
+  case DB_ONECOLUMN:
   case DB_EVAL: {
     char const *zSql;      /* Next SQL statement to execute */
     char const *zLeft;     /* What is left after first stmt in zSql */
@@ -701,13 +635,21 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
     Tcl_Obj **apParm;      /* Parameters that need a Tcl_DecrRefCount() */
     int nParm;             /* Number of entries used in apParm[] */
     Tcl_Obj *aParm[10];    /* Static space for apParm[] in the common case */
+    Tcl_Obj *pRet;         /* Value to be returned */
 
-    Tcl_Obj *pRet = Tcl_NewObj();
-    Tcl_IncrRefCount(pRet);
-
-    if( objc<3 || objc>5 ){
-      Tcl_WrongNumArgs(interp, 2, objv, "SQL ?ARRAY-NAME? ?SCRIPT?");
-      return TCL_ERROR;
+    if( choice==DB_ONECOLUMN ){
+      if( objc!=3 ){
+        Tcl_WrongNumArgs(interp, 2, objv, "SQL");
+        return TCL_ERROR;
+      }
+      pRet = 0;
+    }else{
+      if( objc<3 || objc>5 ){
+        Tcl_WrongNumArgs(interp, 2, objv, "SQL ?ARRAY-NAME? ?SCRIPT?");
+        return TCL_ERROR;
+      }
+      pRet = Tcl_NewObj();
+      Tcl_IncrRefCount(pRet);
     }
     if( objc==3 ){
       pArray = pScript = 0;
@@ -784,7 +726,6 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
           }
         }
       }
-   
 
       /* Compute column names */
       nCol = sqlite3_column_count(pStmt);
@@ -848,6 +789,12 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
             }else{
               Tcl_ObjSetVar2(interp, pArray, apColName[i], pVal, 0);
             }
+          }else if( choice==DB_ONECOLUMN ){
+            if( pRet==0 ){
+              pRet = pVal;
+              Tcl_IncrRefCount(pRet);
+            }
+            goto end_step;
           }else{
             Tcl_ListObjAppendElement(interp, pRet, pVal);
           }
@@ -858,6 +805,7 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
           if( rc!=TCL_ERROR ) rc = TCL_OK;
         }
       }
+    end_step:
 
       /* Free the column name objects */
       if( pScript ){
@@ -892,10 +840,12 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
     }
     Tcl_DecrRefCount(objv[2]);
 
-    if( rc==TCL_OK ){
-      Tcl_SetObjResult(interp, pRet);
+    if( pRet ){
+      if( rc==TCL_OK ){
+        Tcl_SetObjResult(interp, pRet);
+      }
+      Tcl_DecrRefCount(pRet);
     }
-    Tcl_DecrRefCount(pRet);
 
     break;
   }
@@ -949,29 +899,48 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
   }
 
   /*
-  **     $db onecolumn SQL
-  **
-  ** Return a single column from a single row of the given SQL query.
+  ** The DB_ONECOLUMN method is implemented together with DB_EVAL.
   */
-  case DB_ONECOLUMN: {
-    char *zSql;
-    char *zErrMsg = 0;
-    if( objc!=3 ){
-      Tcl_WrongNumArgs(interp, 2, objv, "SQL");
+
+  /*    $db progress ?N CALLBACK?
+  ** 
+  ** Invoke the given callback every N virtual machine opcodes while executing
+  ** queries.
+  */
+  case DB_PROGRESS: {
+    if( objc==2 ){
+      if( pDb->zProgress ){
+        Tcl_AppendResult(interp, pDb->zProgress, 0);
+      }
+    }else if( objc==4 ){
+      char *zProgress;
+      int len;
+      int N;
+      if( TCL_OK!=Tcl_GetIntFromObj(interp, objv[2], &N) ){
+	return TCL_ERROR;
+      };
+      if( pDb->zProgress ){
+        Tcl_Free(pDb->zProgress);
+      }
+      zProgress = Tcl_GetStringFromObj(objv[3], &len);
+      if( zProgress && len>0 ){
+        pDb->zProgress = Tcl_Alloc( len + 1 );
+        strcpy(pDb->zProgress, zProgress);
+      }else{
+        pDb->zProgress = 0;
+      }
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+      if( pDb->zProgress ){
+        pDb->interp = interp;
+        sqlite3_progress_handler(pDb->db, N, DbProgressHandler, pDb);
+      }else{
+        sqlite3_progress_handler(pDb->db, 0, 0, 0);
+      }
+#endif
+    }else{
+      Tcl_WrongNumArgs(interp, 2, objv, "N CALLBACK");
       return TCL_ERROR;
     }
-    zSql = Tcl_GetStringFromObj(objv[2], 0);
-    rc = sqlite3_exec(pDb->db, zSql, DbEvalCallback3, interp, &zErrMsg);
-    if( rc==SQLITE_ABORT ){
-      rc = SQLITE_OK;
-    }else if( zErrMsg ){
-      Tcl_SetResult(interp, zErrMsg, TCL_VOLATILE);
-      free(zErrMsg);
-      rc = TCL_ERROR;
-    }else if( rc!=SQLITE_OK ){
-      Tcl_AppendResult(interp, sqlite3ErrStr(rc), 0);
-      rc = TCL_ERROR;
-    }
     break;
   }