subversion/libsvn_diff/diff.c

   1 /*
   2  * diff.c :  routines for doing diffs
   3  *
   4  * ====================================================================
   5  * Copyright (c) 2000-2004 CollabNet.  All rights reserved.
   6  *
   7  * This software is licensed as described in the file COPYING, which
   8  * you should have received as part of this distribution.  The terms
   9  * are also available at http://subversion.tigris.org/license-1.html.
  10  * If newer versions of this license are posted there, you may use a
  11  * newer version instead, at your option.
  12  *
  13  * This software consists of voluntary contributions made by many
  14  * individuals.  For exact contribution history, see the revision
  15  * history and logs, available at http://subversion.tigris.org/.
  16  * ====================================================================
  17  */
  18
  19
  20 #include <apr.h>
  21 #include <apr_pools.h>
  22 #include <apr_general.h>
  23
  24 #include "svn_pools.h"
  25 #include "svn_error.h"
  26 #include "svn_diff.h"
  27 #include "svn_types.h"
  28
  29 #include "diff.h"
  30
  31
  32 svn_diff_t *
  33 svn_diff__diff(svn_diff__lcs_t *lcs,
  34                apr_off_t original_start, apr_off_t modified_start,
  35                svn_boolean_t want_common,
  36                apr_pool_t *pool)
  37 {
  38   svn_diff_t *diff;
  39   svn_diff_t **diff_ref = &diff;
  40
  41   while (1)
  42     {
  43       if (original_start < lcs->position[0]->offset
  44           || modified_start < lcs->position[1]->offset)
  45       {
  46           (*diff_ref) = apr_palloc(pool, sizeof(**diff_ref));
  47
  48           (*diff_ref)->type = svn_diff__type_diff_modified;
  49           (*diff_ref)->original_start = original_start - 1;
  50           (*diff_ref)->original_length =
  51             lcs->position[0]->offset - original_start;
  52           (*diff_ref)->modified_start = modified_start - 1;
  53           (*diff_ref)->modified_length =
  54             lcs->position[1]->offset - modified_start;
  55           (*diff_ref)->latest_start = 0;
  56           (*diff_ref)->latest_length = 0;
  57
  58           diff_ref = &(*diff_ref)->next;
  59       }
  60
  61       /* Detect the EOF */
  62       if (lcs->length == 0)
  63           break;
  64
  65       original_start = lcs->position[0]->offset;
  66       modified_start = lcs->position[1]->offset;
  67
  68       if (want_common)
  69         {
  70           (*diff_ref) = apr_palloc(pool, sizeof(**diff_ref));
  71
  72           (*diff_ref)->type = svn_diff__type_common;
  73           (*diff_ref)->original_start = original_start - 1;
  74           (*diff_ref)->original_length = lcs->length;
  75           (*diff_ref)->modified_start = modified_start - 1;
  76           (*diff_ref)->modified_length = lcs->length;
  77           (*diff_ref)->latest_start = 0;
  78           (*diff_ref)->latest_length = 0;
  79
  80           diff_ref = &(*diff_ref)->next;
  81         }
  82
  83       original_start += lcs->length;
  84       modified_start += lcs->length;
  85
  86       lcs = lcs->next;
  87     }
  88
  89   *diff_ref = NULL;
  90
  91   return diff;
  92 }
  93
  94
  95 svn_error_t *
  96 svn_diff_diff(svn_diff_t **diff,
  97               void *diff_baton,
  98               const svn_diff_fns_t *vtable,
  99               apr_pool_t *pool)
 100 {
 101   svn_diff__tree_t *tree;
 102   svn_diff__position_t *position_list[2];
 103   svn_diff__lcs_t *lcs;
 104   apr_pool_t *subpool;
 105   apr_pool_t *treepool;
 106
 107   *diff = NULL;
 108
 109   subpool = svn_pool_create(pool);
 110   treepool = svn_pool_create(pool);
 111
 112   svn_diff__tree_create(&tree, treepool);
 113
 114   /* Insert the data into the tree */
 115   SVN_ERR(svn_diff__get_tokens(&position_list[0],
 116                                tree,
 117                                diff_baton, vtable,
 118                                svn_diff_datasource_original,
 119                                subpool));
 120
 121   SVN_ERR(svn_diff__get_tokens(&position_list[1],
 122                                tree,
 123                                diff_baton, vtable,
 124                                svn_diff_datasource_modified,
 125                                subpool));
 126
 127   /* The cool part is that we don't need the tokens anymore.
 128    * Allow the app to clean them up if it wants to.
 129    */
 130   if (vtable->token_discard_all != NULL)
 131     vtable->token_discard_all(diff_baton);
 132
 133   /* We don't need the nodes in the tree either anymore, nor the tree itself */
 134   svn_pool_destroy(treepool);
 135
 136   /* Get the lcs */
 137   lcs = svn_diff__lcs(position_list[0], position_list[1], subpool);
 138
 139   /* Produce the diff */
 140   *diff = svn_diff__diff(lcs, 1, 1, TRUE, pool);
 141
 142   /* Get rid of all the data we don't have a use for anymore */
 143   svn_pool_destroy(subpool);
 144
 145   return SVN_NO_ERROR;
 146 }