[Zope-Checkins] CVS: Zope2 - MergeTemplate.c:1.1.2.1

Jim Fulton jim@digiciool.com
Mon, 12 Mar 2001 11:24:52 -0500 (EST)


Update of /cvs-repository/Zope2/lib/python/BTrees
In directory korak:/tmp/cvs-serv25560

Added Files:
      Tag: Catalog-BTrees-Integration
	MergeTemplate.c 
Log Message:
Added logic for merging conflicting changes.



--- Added File MergeTemplate.c in package Zope2 ---
/*****************************************************************************
  
  Zope Public License (ZPL) Version 1.0
  -------------------------------------
  
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  modification, are permitted provided that the following conditions are
  met:
  
  1. Redistributions in source code must retain the above copyright
     notice, this list of conditions, and the following disclaimer.
  
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     notice, this list of conditions, and the following disclaimer in
     the documentation and/or other materials provided with the
     distribution.
  
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     into Zope, and this effort will continue if the Zope community
     continues to grow. This is one way to assure that growth.
  
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 ****************************************************************************/

/****************************************************************************
 Set operations
 ****************************************************************************/

static int
merge_output(Bucket *r, SetIteration *i, int mapping)
{
  if(r->len >= r->size && Bucket_grow(r, ! mapping) < 0) return -1;
  COPY_KEY(r->keys[r->len], i->key);
  INCREF_KEY(r->keys[r->len]);
  if (mapping)
    {
      COPY_VALUE(r->values[r->len], i->value);
      INCREF_VALUE(r->values[r->len]);
    }
  r->len++;
  return 0;
}

static void
merge_error()
{
  PyErr_SetObject(PyExc_ValueError, Py_None);
}

static PyObject *
bucket_merge(PyObject *s1, PyObject *s2, PyObject *s3)
{
  Bucket *r=0;
  PyObject *s;
  SetIteration i1 = {0,0,0}, i2 = {0,0,0}, i3 = {0,0,0}, it;
  int cmp12, cmp13, cmp23, mapping=0, set;

  if (initSetIteration(&i1, s1, 0, &mapping) < 0) return NULL;
  if (initSetIteration(&i2, s2, 0, &mapping) < 0) return NULL;
  if (initSetIteration(&i3, s3, 0, &mapping) < 0) return NULL;

  set = ! mapping;

  if (mapping)
    {
      UNLESS(r=BUCKET(PyObject_CallObject(OBJECT(&BucketType), NULL)))
        goto err;
    }
  else
    {
      UNLESS(r=BUCKET(PyObject_CallObject(OBJECT(&SetType), NULL)))
        goto err;
    }

  if (i1.next(&i1) < 0) return NULL;
  if (i2.next(&i2) < 0) return NULL;
  if (i3.next(&i3) < 0) return NULL;

  while (i1.position >= 0 && i2.position >= 0 && i3.position >= 0)
    {
      cmp12=TEST_KEY(i1.key, i2.key);
      cmp13=TEST_KEY(i1.key, i3.key);
      if (cmp12==0)
        {
          if (cmp13==0)
            {
              if (set || TEST_VALUE(i1.value, i2.value) == 0)
                {               /* change in i3 or all same */
                  if (merge_output(r, &i3, mapping) < 0) goto err;
                }
              else if (set || TEST_VALUE(i1.value, i3.value) == 0)
                {               /* change in i2 */
                  if (merge_output(r, &i2, mapping) < 0) goto err;
                }
              else
                {               /* conflicting changes in i2 and i3 */
                  merge_error();
                  goto err;
                }
              if (i1.next(&i1) < 0) goto err;
              if (i2.next(&i2) < 0) goto err;
              if (i3.next(&i3) < 0) goto err;
            }
          else if (cmp13 > 0)
            {                   /* insert i3 */
              if (merge_output(r, &i3, mapping) < 0) goto err;
              if (i3.next(&i3) < 0) goto err;
            }
          else if (set || TEST_VALUE(i1.value, i2.value) == 0)
            {                   /* delete i3 */
              if (i1.next(&i1) < 0) goto err;
              if (i2.next(&i2) < 0) goto err;
            }
          else
            {                   /* conflicting del in i3 and change in i2 */
              merge_error();
              goto err;
            }
        }
      else if (cmp13 == 0)
        {
          if (cmp12 > 0)
            {                   /* insert i2 */
              if (merge_output(r, &i2, mapping) < 0) goto err;
              if (i2.next(&i2) < 0) goto err;
            }
          else if (set || TEST_VALUE(i1.value, i3.value) == 0)
            {                   /* delete i2 */
              if (i1.next(&i1) < 0) goto err;
              if (i3.next(&i3) < 0) goto err;
            }
          else
            {                   /* conflicting del in i2 and change in i3 */
              merge_error();
              goto err;
            }
        }
      else
        {                       /* Both keys changed */
          cmp23=TEST_KEY(i2.key, i3.key);
          if (cmp23==0)
            {                   /* dualing inserts */
              merge_error();
              goto err;
            }
          if (cmp12 > 0)
            {                   /* insert i2 */
              if (cmp23 > 0)
                {               /* insert i3 first */
                  if (merge_output(r, &i3, mapping) < 0) goto err;
                  if (i3.next(&i3) < 0) goto err;
                }
              else
                {               /* insert i2 first */
                  if (merge_output(r, &i2, mapping) < 0) goto err;
                  if (i2.next(&i2) < 0) goto err;
                }
            }
          else if (cmp13 > 0)
            {                   /* Insert i3 */
              if (merge_output(r, &i3, mapping) < 0) goto err;
              if (i3.next(&i3) < 0) goto err;
            }
          else
            {                   /* Dueling deletes */
              merge_error();
              goto err;
            }
        }
    }

  while (i2.position >= 0 && i3.position >= 0)
    {                           /* New inserts */
      cmp23=TEST_KEY(i2.key, i3.key);
      if (cmp23==0)
        {                       /* dualing inserts */
          merge_error();
          goto err;
        }
      if (cmp23 > 0)
        {                       /* insert i3 */
          if (merge_output(r, &i3, mapping) < 0) goto err;
          if (i3.next(&i3) < 0) goto err;
        }
      else
        {                       /* insert i2 */
          if (merge_output(r, &i2, mapping) < 0) goto err;
          if (i2.next(&i2) < 0) goto err;
        }
    }

  while (i1.position >= 0 && i2.position >= 0)
    {                           /* deleting i3 */
      cmp12=TEST_KEY(i1.key, i2.key);
      if (cmp12 > 0)
        {                       /* insert i2 */
          if (merge_output(r, &i2, mapping) < 0) goto err;
          if (i2.next(&i2) < 0) goto err;
        }
      else if (cmp12==0 && (set || TEST_VALUE(i1.value, i2.value) == 0))
        {                       /* delete i3 */
          if (i1.next(&i1) < 0) goto err;
          if (i2.next(&i3) < 0) goto err;
        }
      else
        {                       /* Dualing deletes or delete and change */
          merge_error();
          goto err;
        }
    }

  while (i1.position >= 0 && i3.position >= 0)
    {                           /* deleting i2 */
      cmp13=TEST_KEY(i1.key, i3.key);
      if (cmp13 > 0)
        {                       /* insert i3 */
          if (merge_output(r, &i3, mapping) < 0) goto err;
          if (i3.next(&i3) < 0) goto err;
        }
      else if (cmp13==0 && (set || TEST_VALUE(i1.value, i3.value) == 0))
        {                       /* delete i2 */
          if (i1.next(&i1) < 0) goto err;
          if (i3.next(&i3) < 0) goto err;
        }
      else
        {                       /* Dualing deletes or delete and change */
          merge_error();
          goto err;
        }
    }

  if (i1.position >= 0)
    {                           /* Dueling deletes */
      merge_error();
      goto err;
    }

  while (i2.position >= 0)
    {                           /* Inserting i2 at end */
      if (merge_output(r, &i2, mapping) < 0) goto err;
      if (i2.next(&i2) < 0) goto err;
    }

  while (i3.position >= 0)
    {                           /* Inserting i2 at end */
      if (merge_output(r, &i3, mapping) < 0) goto err;
      if (i3.next(&i3) < 0) goto err;
    }
  
  Py_DECREF(i1.set);
  Py_DECREF(i2.set);
  Py_DECREF(i3.set);

  s=bucket_getstate(r, NULL);
  Py_DECREF(r);

  return s;

invalid_set_operation:
  PyErr_SetString(PyExc_TypeError, "invalid set operation");
err:
  Py_XDECREF(i1.set);
  Py_XDECREF(i2.set);
  Py_XDECREF(i3.set);
  Py_XDECREF(r);
  return NULL;
}