Remove all maintenance of a string result in the Interp.

1 files changed, 20 insertions, 47 deletions

diff --git a/generic/tclInt.h b/generic/tclInt.h
index 8110248..5192688 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -1799,42 +1799,33 @@ typedef struct AllocCache {
  */
 
 typedef struct Interp {
+
     /*
-     * Note: the first three fields must match exactly the fields in a
-     * Tcl_Interp struct (see tcl.h). If you change one, be sure to change the
-     * other.
-     *
-     * The interpreter's result is held in both the string and the
-     * objResultPtr fields. These fields hold, respectively, the result's
-     * string or object value. The interpreter's result is always in the
-     * result field if that is non-empty, otherwise it is in objResultPtr.
-     * The two fields are kept consistent unless some C code sets
-     * interp->result directly. Programs should not access result and
-     * objResultPtr directly; instead, they should always get and set the
-     * result using procedures such as Tcl_SetObjResult, Tcl_GetObjResult, and
-     * Tcl_GetStringResult. See the SetResult man page for details.
+     * The first two fields were named "result" and "freeProc" in earlier
+     * versions of Tcl.  They are no longer used within Tcl, and are no
+     * longer available to be accessed by extensions.  However, they cannot
+     * be removed.  Why?  There is a deployed base of stub-enabled extensions
+     * that query the value of iPtr->stubTable.  For them to continue to work,
+     * the location of the field "stubTable" within the Interp struct cannot
+     * change.  The most robust way to assure that is to leave all fields up to
+     * that one undisturbed.
      */
 
-    char *result;		/* If the last command returned a string
-				 * result, this points to it. Should not be
-				 * accessed directly; see comment above. */
-    Tcl_FreeProc *freeProc;	/* Zero means a string result is statically
-				 * allocated. TCL_DYNAMIC means string result
-				 * was allocated with ckalloc and should be
-				 * freed with ckfree. Other values give
-				 * address of procedure to invoke to free the
-				 * string result. Tcl_Eval must free it before
-				 * executing next command. */
+    char *legacyResult;
+    Tcl_FreeProc *legacyFreeProc;
     int errorLine;		/* When TCL_ERROR is returned, this gives the
 				 * line number in the command where the error
 				 * occurred (1 means first line). */
     const struct TclStubs *stubTable;
-				/* Pointer to the exported Tcl stub table. On
-				 * previous versions of Tcl this is a pointer
-				 * to the objResultPtr or a pointer to a
-				 * buckets array in a hash table. We therefore
-				 * have to do some careful checking before we
-				 * can use this. */
+				/* Pointer to the exported Tcl stub table.  In
+				 * ancient pre-8.1 versions of Tcl this was a
+				 * pointer to the objResultPtr or a pointer to a
+				 * buckets array in a hash table. Deployed stubs
+				 * enabled extensions check for a NULL pointer value
+				 * and for a TCL_STUBS_MAGIC value to verify they
+				 * are not [load]ing into one of those pre-stubs
+				 * interps.
+				 */
 
     TclHandle handle;		/* Handle used to keep track of when this
 				 * interp is deleted. */
@@ -1847,8 +1838,6 @@ typedef struct Interp {
     ClientData interpInfo;	/* Information used by tclInterp.c to keep
 				 * track of master/slave interps on a
 				 * per-interp basis. */
-    Tcl_HashTable unused2;	/* No longer used (was mathFuncTable) */
-
     /*
      * Information related to procedures and variables. See tclProc.c and
      * tclVar.c for usage.
@@ -1878,19 +1867,6 @@ typedef struct Interp {
 				 * TCL_EVAL_INVOKE call to Tcl_EvalObjv. */
 
     /*
-     * Information used by Tcl_AppendResult to keep track of partial results.
-     * See Tcl_AppendResult code for details.
-     */
-
-    char *appendResult;		/* Storage space for results generated by
-				 * Tcl_AppendResult. Ckalloc-ed. NULL means
-				 * not yet allocated. */
-    int appendAvl;		/* Total amount of space available at
-				 * partialResult. */
-    int appendUsed;		/* Number of non-null bytes currently stored
-				 * at partialResult. */
-
-    /*
      * Information about packages. Used only in tclPkg.c.
      */
 
@@ -1912,7 +1888,6 @@ typedef struct Interp {
 				 * Normally zero, but may be set before
 				 * calling Tcl_Eval. See below for valid
 				 * values. */
-    int unused1;		/* No longer used (was termOffset) */
     LiteralTable literalTable;	/* Contains LiteralEntry's describing all Tcl
 				 * objects holding literals of scripts
 				 * compiled by the interpreter. Indexed by the
@@ -1950,8 +1925,6 @@ typedef struct Interp {
 				 * string. Returned by Tcl_ObjSetVar2 when
 				 * variable traces change a variable in a
 				 * gross way. */
-    char resultSpace[TCL_RESULT_SIZE+1];
-				/* Static space holding small results. */
     Tcl_Obj *objResultPtr;	/* If the last command returned an object
 				 * result, this points to it. Should not be
 				 * accessed directly; see comment above. */