/*

 * Copyright (C) 2005 Junio C Hamano

 */

#define USE_THE_REPOSITORY_VARIABLE

#define DISABLE_SIGN_COMPARE_WARNINGS

#include "git-compat-util.h"

#include "commit.h"

#include "diff.h"

#include "diffcore.h"

#include "gettext.h"

#include "hash.h"

#include "hex.h"

#include "object-name.h"

#include "read-cache.h"

#include "revision.h"

#include "cache-tree.h"

#include "unpack-trees.h"

#include "refs.h"

#include "repository.h"

#include "submodule.h"

#include "symlinks.h"

#include "trace.h"

#include "dir.h"

#include "fsmonitor.h"

#include "commit-reach.h"

/*

 * diff-files

 */

/*

 * Has the work tree entity been removed?

 *

 * Return 1 if it was removed from the work tree, 0 if an entity to be

 * compared with the cache entry ce still exists (the latter includes

 * the case where a directory that is not a submodule repository

 * exists for ce that is a submodule -- it is a submodule that is not

 * checked out).  Return negative for an error.

 */

static int check_removed(const struct cache_entry *ce, struct stat *st)

{

  int stat_err;

  if (!(ce->ce_flags & CE_FSMONITOR_VALID))

    stat_err = lstat(ce->name, st);

  else

    stat_err = fake_lstat(ce, st);

  if (stat_err < 0) {

    if (!is_missing_file_error(errno))

      return -1;

    return 1;

  }

  if (has_symlink_leading_path(ce->name, ce_namelen(ce)))

    return 1;

  if (S_ISDIR(st->st_mode)) {

    struct object_id sub;

    /*

     * If ce is already a gitlink, we can have a plain

     * directory (i.e. the submodule is not checked out),

     * or a checked out submodule.  Either case this is not

     * a case where something was removed from the work tree,

     * so we will return 0.

     *

     * Otherwise, if the directory is not a submodule

     * repository, that means ce which was a blob turned into

     * a directory --- the blob was removed!

     */

    if (!S_ISGITLINK(ce->ce_mode) &&

        repo_resolve_gitlink_ref(the_repository, ce->name,

               "HEAD", &sub))

      return 1;

  }

  return 0;

}

/*

 * Has a file changed or has a submodule new commits or a dirty work tree?

 *

 * Return 1 when changes are detected, 0 otherwise. If the DIRTY_SUBMODULES

 * option is set, the caller does not only want to know if a submodule is

 * modified at all but wants to know all the conditions that are met (new

 * commits, untracked content and/or modified content).

 */

static int match_stat_with_submodule(struct diff_options *diffopt,

             const struct cache_entry *ce,

             struct stat *st, unsigned ce_option,

             unsigned *dirty_submodule)

{

  int changed = ie_match_stat(diffopt->repo->index, ce, st, ce_option);

  if (S_ISGITLINK(ce->ce_mode)) {

    struct diff_flags orig_flags = diffopt->flags;

    if (!diffopt->flags.override_submodule_config)

      set_diffopt_flags_from_submodule_config(diffopt, ce->name);

    if (diffopt->flags.ignore_submodules)

      changed = 0;

    else if (!diffopt->flags.ignore_dirty_submodules &&

       (!changed || diffopt->flags.dirty_submodules))

      *dirty_submodule = is_submodule_modified(ce->name,

                 diffopt->flags.ignore_untracked_in_submodules);

    diffopt->flags = orig_flags;

  }

  return changed;

}

void run_diff_files(struct rev_info *revs, unsigned int option)

{

  int entries, i;

  int diff_unmerged_stage = revs->max_count;

  unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)

            ? CE_MATCH_RACY_IS_DIRTY : 0);

  uint64_t start = getnanotime();

  struct index_state *istate = revs->diffopt.repo->index;

  if (revs->diffopt.max_depth_valid)

    die(_("max-depth is not supported for worktree diffs"));

  diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");

  refresh_fsmonitor(istate);

  if (diff_unmerged_stage < 0)

    diff_unmerged_stage = 2;

  entries = istate->cache_nr;

  for (i = 0; i < entries; i++) {

    unsigned int oldmode, newmode;

    struct cache_entry *ce = istate->cache[i];

    int changed;

    unsigned dirty_submodule = 0;

    const struct object_id *old_oid, *new_oid;

    if (diff_can_quit_early(&revs->diffopt))

      break;

    /*

     * NEEDSWORK:

     * Here we filter with pathspec but the result is further

     * filtered out when --relative is in effect.  To end-users,

     * a pathspec element that matched only to paths outside the

     * current directory is like not matching anything at all;

     * the handling of ps_matched[] here may become problematic

     * if/when we add the "--error-unmatch" option to "git diff".

     */

    if (!ce_path_match(istate, ce, &revs->prune_data, revs->ps_matched))

      continue;

    if (revs->diffopt.prefix &&

        strncmp(ce->name, revs->diffopt.prefix, revs->diffopt.prefix_length))

      continue;

    if (ce_stage(ce)) {

      struct combine_diff_path *dpath;

      struct diff_filepair *pair;

      unsigned int wt_mode = 0;

      int num_compare_stages = 0;

      struct stat st;

      changed = check_removed(ce, &st);

      if (!changed)

        wt_mode = ce_mode_from_stat(ce, st.st_mode);

      else {

        if (changed < 0) {

          perror(ce->name);

          continue;

        }

        wt_mode = 0;

      }

      /*

       * Allocate space for two parents, which will come from

       * index stages #2 and #3, if present. Below we'll fill

       * these from (stage - 2).

       */

      dpath = combine_diff_path_new(ce->name, ce_namelen(ce),

                  wt_mode, null_oid(the_hash_algo), 2);

      while (i < entries) {

        struct cache_entry *nce = istate->cache[i];

        int stage;

        if (strcmp(ce->name, nce->name))

          break;

        /* Stage #2 (ours) is the first parent,

         * stage #3 (theirs) is the second.

         */

        stage = ce_stage(nce);

        if (2 <= stage) {

          int mode = nce->ce_mode;

          num_compare_stages++;

          oidcpy(&dpath->parent[stage - 2].oid,

                 &nce->oid);

          dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);

          dpath->parent[stage-2].status =

            DIFF_STATUS_MODIFIED;

        }

        /* diff against the proper unmerged stage */

        if (stage == diff_unmerged_stage)

          ce = nce;

        i++;

      }

      /*

       * Compensate for loop update

       */

      i--;

      if (revs->combine_merges && num_compare_stages == 2) {

        show_combined_diff(dpath, 2, revs);

        free(dpath);

        continue;

      }

      FREE_AND_NULL(dpath);

      /*

       * Show the diff for the 'ce' if we found the one

       * from the desired stage.

       */

      pair = diff_unmerge(&revs->diffopt, ce->name);

      if (wt_mode)

        pair->two->mode = wt_mode;

      if (ce_stage(ce) != diff_unmerged_stage)

        continue;

    }

    if (ce_uptodate(ce) || ce_skip_worktree(ce)) {

      if (revs->diffopt.flags.find_copies_harder)

        diff_same(&revs->diffopt, ce->ce_mode,

            &ce->oid, ce->name);

      continue;

    }

    /*

     * When CE_VALID is set (via "update-index --assume-unchanged"

     * or via adding paths while core.ignorestat is set to true),

     * the user has promised that the working tree file for that

     * path will not be modified.  When CE_FSMONITOR_VALID is true,

     * the fsmonitor knows that the path hasn't been modified since

     * we refreshed the cached stat information.  In either case,

     * we do not have to stat to see if the path has been removed

     * or modified.

     */

    if (ce->ce_flags & (CE_VALID | CE_FSMONITOR_VALID)) {

      changed = 0;

      newmode = ce->ce_mode;

    } else {

      struct stat st;

      changed = check_removed(ce, &st);

      if (changed) {

        if (changed < 0) {

          perror(ce->name);

          continue;

        }

        diff_addremove(&revs->diffopt, '-', ce->ce_mode,

                 &ce->oid,

                 !is_null_oid(&ce->oid),

                 ce->name, 0);

        continue;

      } else if (revs->diffopt.ita_invisible_in_index &&

           ce_intent_to_add(ce)) {

        newmode = ce_mode_from_stat(ce, st.st_mode);

        diff_addremove(&revs->diffopt, '+', newmode,

                 null_oid(the_hash_algo), 0, ce->name, 0);

        continue;

      }

      changed = match_stat_with_submodule(&revs->diffopt, ce, &st,

                  ce_option, &dirty_submodule);

      newmode = ce_mode_from_stat(ce, st.st_mode);

    }

    if (!changed && !dirty_submodule) {

      ce_mark_uptodate(ce);

      mark_fsmonitor_valid(istate, ce);

      if (revs->diffopt.flags.find_copies_harder)

        diff_same(&revs->diffopt, newmode,

            &ce->oid, ce->name);

      continue;

    }

    oldmode = ce->ce_mode;

    old_oid = &ce->oid;

    new_oid = changed ? null_oid(the_hash_algo) : &ce->oid;

    diff_change(&revs->diffopt, oldmode, newmode,

          old_oid, new_oid,

          !is_null_oid(old_oid),

          !is_null_oid(new_oid),

          ce->name, 0, dirty_submodule);

  }

  diffcore_std(&revs->diffopt);

  diff_flush(&revs->diffopt);

  trace_performance_since(start, "diff-files");

}

/*

 * diff-index

 */

/* A file entry went away or appeared */

static void diff_index_show_file(struct rev_info *revs,

         const char *prefix,

         const struct cache_entry *ce,

         const struct object_id *oid, int oid_valid,

         unsigned int mode,

         unsigned dirty_submodule)

{

  diff_addremove(&revs->diffopt, prefix[0], mode,

           oid, oid_valid, ce->name, dirty_submodule);

}

static int get_stat_data(const struct cache_entry *ce,

       const struct object_id **oidp,

       unsigned int *modep,

       int cached, int match_missing,

       unsigned *dirty_submodule, struct diff_options *diffopt)

{

  const struct object_id *oid = &ce->oid;

  unsigned int mode = ce->ce_mode;

  if (!cached && !ce_uptodate(ce)) {

    int changed;

    struct stat st;

    changed = check_removed(ce, &st);

    if (changed < 0)

      return -1;

    else if (changed) {

      if (match_missing) {

        *oidp = oid;

        *modep = mode;

        return 0;

      }

      return -1;

    }

    changed = match_stat_with_submodule(diffopt, ce, &st,

                0, dirty_submodule);

    if (changed) {

      mode = ce_mode_from_stat(ce, st.st_mode);

      oid = null_oid(the_hash_algo);

    }

  }

  *oidp = oid;

  *modep = mode;

  return 0;

}

static void show_new_file(struct rev_info *revs,

        const struct cache_entry *new_file,

        int cached, int match_missing)

{

  const struct object_id *oid;

  unsigned int mode;

  unsigned dirty_submodule = 0;

  if (new_file && S_ISSPARSEDIR(new_file->ce_mode)) {

    diff_tree_oid(NULL, &new_file->oid, new_file->name, &revs->diffopt);

    return;

  }

  /*

   * New file in the index: it might actually be different in

   * the working tree.

   */

  if (get_stat_data(new_file, &oid, &mode, cached, match_missing,

      &dirty_submodule, &revs->diffopt) < 0)

    return;

  diff_index_show_file(revs, "+", new_file, oid, !is_null_oid(oid), mode, dirty_submodule);

}

static int show_modified(struct rev_info *revs,

       const struct cache_entry *old_entry,

       const struct cache_entry *new_entry,

       int report_missing,

       int cached, int match_missing)

{

  unsigned int mode, oldmode;

  const struct object_id *oid;

  unsigned dirty_submodule = 0;

  assert(S_ISSPARSEDIR(old_entry->ce_mode) ==

         S_ISSPARSEDIR(new_entry->ce_mode));

  /*

   * If both are sparse directory entries, then expand the

   * modifications to the file level. If only one was a sparse

   * directory, then they appear as an add and delete instead of

   * a modification.

   */

  if (S_ISSPARSEDIR(new_entry->ce_mode)) {

    diff_tree_oid(&old_entry->oid, &new_entry->oid, new_entry->name, &revs->diffopt);

    return 0;

  }

  if (get_stat_data(new_entry, &oid, &mode, cached, match_missing,

        &dirty_submodule, &revs->diffopt) < 0) {

    if (report_missing)

      diff_index_show_file(revs, "-", old_entry,

               &old_entry->oid, 1, old_entry->ce_mode,

               0);

    return -1;

  }

  if (revs->combine_merges && !cached &&

      (!oideq(oid, &old_entry->oid) || !oideq(&old_entry->oid, &new_entry->oid))) {

    struct combine_diff_path *p;

    p = combine_diff_path_new(new_entry->name,

            ce_namelen(new_entry),

            mode, null_oid(the_hash_algo), 2);

    p->parent[0].status = DIFF_STATUS_MODIFIED;

    p->parent[0].mode = new_entry->ce_mode;

    oidcpy(&p->parent[0].oid, &new_entry->oid);

    p->parent[1].status = DIFF_STATUS_MODIFIED;

    p->parent[1].mode = old_entry->ce_mode;

    oidcpy(&p->parent[1].oid, &old_entry->oid);

    show_combined_diff(p, 2, revs);

    free(p);

    return 0;

  }

  oldmode = old_entry->ce_mode;

  if (mode != oldmode || !oideq(oid, &old_entry->oid) || dirty_submodule)

    diff_change(&revs->diffopt, oldmode, mode,

          &old_entry->oid, oid, 1, !is_null_oid(oid),

          old_entry->name, 0, dirty_submodule);

  else if (revs->diffopt.flags.find_copies_harder)

    diff_same(&revs->diffopt, mode, oid, old_entry->name);

  return 0;

}

/*

 * This gets a mix of an existing index and a tree, one pathname entry

 * at a time. The index entry may be a single stage-0 one, but it could

 * also be multiple unmerged entries (in which case idx_pos/idx_nr will

 * give you the position and number of entries in the index).

 */

static void do_oneway_diff(struct unpack_trees_options *o,

         const struct cache_entry *idx,

         const struct cache_entry *tree)

{

  struct rev_info *revs = o->unpack_data;

  int match_missing, cached;

  /*

   * i-t-a entries do not actually exist in the index (if we're

   * looking at its content)

   */

  if (o->index_only &&

      revs->diffopt.ita_invisible_in_index &&

      idx && ce_intent_to_add(idx)) {

    idx = NULL;

    if (!tree)

      return; /* nothing to diff.. */

  }

  /* if the entry is not checked out, don't examine work tree */

  cached = o->index_only ||

    (idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));

  match_missing = revs->match_missing;

  if (cached && idx && ce_stage(idx)) {

    struct diff_filepair *pair;

    pair = diff_unmerge(&revs->diffopt, idx->name);

    if (tree)

      fill_filespec(pair->one, &tree->oid, 1,

              tree->ce_mode);

    return;

  }

  /*

   * Something added to the tree?

   */

  if (!tree) {

    show_new_file(revs, idx, cached, match_missing);

    return;

  }

  /*

   * Something removed from the tree?

   */

  if (!idx) {

    if (S_ISSPARSEDIR(tree->ce_mode)) {

      diff_tree_oid(&tree->oid, NULL, tree->name, &revs->diffopt);

      return;

    }

    diff_index_show_file(revs, "-", tree, &tree->oid, 1,

             tree->ce_mode, 0);

    return;

  }

  /* Show difference between old and new */

  show_modified(revs, tree, idx, 1, cached, match_missing);

}

/*

 * The unpack_trees() interface is designed for merging, so

 * the different source entries are designed primarily for

 * the source trees, with the old index being really mainly

 * used for being replaced by the result.

 *

 * For diffing, the index is more important, and we only have a

 * single tree.

 *

 * We're supposed to advance o->pos to skip what we have already processed.

 *

 * This wrapper makes it all more readable, and takes care of all

 * the fairly complex unpack_trees() semantic requirements, including

 * the skipping, the path matching, the type conflict cases etc.

 */

static int oneway_diff(const struct cache_entry * const *src,

           struct unpack_trees_options *o)

{

  const struct cache_entry *idx = src[0];

  const struct cache_entry *tree = src[1];

  struct rev_info *revs = o->unpack_data;

  /*

   * Unpack-trees generates a DF/conflict entry if

   * there was a directory in the index and a tree

   * in the tree. From a diff standpoint, that's a

   * delete of the tree and a create of the file.

   */

  if (tree == o->df_conflict_entry)

    tree = NULL;

  if (ce_path_match(revs->diffopt.repo->index,

        idx ? idx : tree,

        &revs->prune_data, NULL)) {

    do_oneway_diff(o, idx, tree);

    if (diff_can_quit_early(&revs->diffopt)) {

      o->exiting_early = 1;

      return -1;

    }

  }

  return 0;

}

static int diff_cache(struct rev_info *revs,

          const struct object_id *tree_oid,

          const char *tree_name,

          int cached)

{

  struct tree *tree;

  struct tree_desc t;

  struct unpack_trees_options opts;

  tree = parse_tree_indirect(tree_oid);

  if (!tree)

    return error("bad tree object %s",

           tree_name ? tree_name : oid_to_hex(tree_oid));

  memset(&opts, 0, sizeof(opts));

  opts.head_idx = 1;

  opts.index_only = cached;

  opts.diff_index_cached = (cached &&

          !revs->diffopt.flags.find_copies_harder);

  opts.merge = 1;

  opts.fn = oneway_diff;

  opts.unpack_data = revs;

  opts.src_index = revs->diffopt.repo->index;

  opts.dst_index = NULL;

  opts.pathspec = &revs->diffopt.pathspec;

  opts.pathspec->recursive = 1;

  if (revs->diffopt.max_depth_valid)

    die(_("max-depth is not supported for index diffs"));

  init_tree_desc(&t, &tree->object.oid, tree->buffer, tree->size);

  return unpack_trees(1, &t, &opts);

}

void diff_get_merge_base(const struct rev_info *revs, struct object_id *mb)

{

  int i;

  struct commit *mb_child[2] = {0};

  struct commit_list *merge_bases = NULL;

  for (i = 0; i < revs->pending.nr; i++) {

    struct object *obj = revs->pending.objects[i].item;

    if (obj->flags)

      die(_("--merge-base does not work with ranges"));

  }

  /*

   * This check must go after the for loop above because A...B

   * ranges produce three pending commits, resulting in a

   * misleading error message.

   */

  if (revs->pending.nr < 1 || revs->pending.nr > 2)

    BUG("unexpected revs->pending.nr: %d", revs->pending.nr);

  for (i = 0; i < revs->pending.nr; i++)

    mb_child[i] = lookup_commit_reference(the_repository, &revs->pending.objects[i].item->oid);

  if (revs->pending.nr == 1) {

    struct object_id oid;

    if (repo_get_oid(the_repository, "HEAD", &oid))

      die(_("unable to get HEAD"));

    mb_child[1] = lookup_commit_reference(the_repository, &oid);

  }

  if (repo_get_merge_bases(the_repository, mb_child[0], mb_child[1], &merge_bases) < 0)

    exit(128);

  if (!merge_bases)

    die(_("no merge base found"));

  if (merge_bases->next)

    die(_("multiple merge bases found"));

  oidcpy(mb, &merge_bases->item->object.oid);

  free_commit_list(merge_bases);

}

void run_diff_index(struct rev_info *revs, unsigned int option)

{

  struct object_array_entry *ent;

  int cached = !!(option & DIFF_INDEX_CACHED);

  int merge_base = !!(option & DIFF_INDEX_MERGE_BASE);

  struct object_id oid;

  const char *name;

  char merge_base_hex[GIT_MAX_HEXSZ + 1];

  struct index_state *istate = revs->diffopt.repo->index;

  if (revs->pending.nr != 1)

    BUG("run_diff_index must be passed exactly one tree");

  trace_performance_enter();

  ent = revs->pending.objects;

  refresh_fsmonitor(istate);

  if (merge_base) {

    diff_get_merge_base(revs, &oid);

    name = oid_to_hex_r(merge_base_hex, &oid);

  } else {

    oidcpy(&oid, &ent->item->oid);

    name = ent->name;

  }

  if (diff_cache(revs, &oid, name, cached))

    exit(128);

  diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");

  diffcore_fix_diff_index();

  diffcore_std(&revs->diffopt);

  diff_flush(&revs->diffopt);

  trace_performance_leave("diff-index");

}

int do_diff_cache(const struct object_id *tree_oid, struct diff_options *opt)

{

  struct rev_info revs;

  repo_init_revisions(opt->repo, &revs, NULL);

  copy_pathspec(&revs.prune_data, &opt->pathspec);

  diff_free(&revs.diffopt);

  revs.diffopt = *opt;

  revs.diffopt.no_free = 1;

  if (diff_cache(&revs, tree_oid, NULL, 1))

    exit(128);

  release_revisions(&revs);

  return 0;

}

int index_differs_from(struct repository *r,

           const char *def, const struct diff_flags *flags,

           int ita_invisible_in_index)

{

  struct rev_info rev;

  struct setup_revision_opt opt;

  unsigned has_changes;

  repo_init_revisions(r, &rev, NULL);

  memset(&opt, 0, sizeof(opt));

  opt.def = def;

  setup_revisions(0, NULL, &rev, &opt);

  rev.diffopt.flags.quick = 1;

  rev.diffopt.flags.exit_with_status = 1;

  if (flags) {

    diff_flags_or(&rev.diffopt.flags, flags);

    /*

     * Now that flags are merged, honor override_submodule_config

     * and ignore_submodules from passed flags.

     */

    if (flags->override_submodule_config)

      rev.diffopt.flags.ignore_submodules = flags->ignore_submodules;

  }

  rev.diffopt.ita_invisible_in_index = ita_invisible_in_index;

  run_diff_index(&rev, DIFF_INDEX_CACHED);

  has_changes = rev.diffopt.flags.has_changes;

  release_revisions(&rev);

  return (has_changes != 0);

}

static const char *idiff_prefix_cb(struct diff_options *opt UNUSED, void *data)

{

  return data;

}

void show_interdiff(const struct object_id *oid1, const struct object_id *oid2,

        int indent, struct diff_options *diffopt)

{

  struct diff_options opts;

  struct strbuf prefix = STRBUF_INIT;

  memcpy(&opts, diffopt, sizeof(opts));

  opts.output_format = DIFF_FORMAT_PATCH;

  opts.output_prefix = idiff_prefix_cb;

  strbuf_addchars(&prefix, ' ', indent);

  opts.output_prefix_data = prefix.buf;

  diff_setup_done(&opts);

  diff_tree_oid(oid1, oid2, "", &opts);

  diffcore_std(&opts);

  diff_flush(&opts);

  strbuf_release(&prefix);

}