diff options
Diffstat (limited to 'merge-ort.c')
| -rw-r--r-- | merge-ort.c | 1987 |
1 files changed, 1987 insertions, 0 deletions
diff --git a/merge-ort.c b/merge-ort.c new file mode 100644 index 0000000000..d36a92b59b --- /dev/null +++ b/merge-ort.c @@ -0,0 +1,1987 @@ +/* + * "Ostensibly Recursive's Twin" merge strategy, or "ort" for short. Meant + * as a drop-in replacement for the "recursive" merge strategy, allowing one + * to replace + * + * git merge [-s recursive] + * + * with + * + * git merge -s ort + * + * Note: git's parser allows the space between '-s' and its argument to be + * missing. (Should I have backronymed "ham", "alsa", "kip", "nap, "alvo", + * "cale", "peedy", or "ins" instead of "ort"?) + */ + +#include "cache.h" +#include "merge-ort.h" + +#include "alloc.h" +#include "blob.h" +#include "cache-tree.h" +#include "commit.h" +#include "commit-reach.h" +#include "diff.h" +#include "diffcore.h" +#include "dir.h" +#include "object-store.h" +#include "strmap.h" +#include "tree.h" +#include "unpack-trees.h" +#include "xdiff-interface.h" + +/* + * We have many arrays of size 3. Whenever we have such an array, the + * indices refer to one of the sides of the three-way merge. This is so + * pervasive that the constants 0, 1, and 2 are used in many places in the + * code (especially in arithmetic operations to find the other side's index + * or to compute a relevant mask), but sometimes these enum names are used + * to aid code clarity. + * + * See also 'filemask' and 'dirmask' in struct conflict_info; the "ith side" + * referred to there is one of these three sides. + */ +enum merge_side { + MERGE_BASE = 0, + MERGE_SIDE1 = 1, + MERGE_SIDE2 = 2 +}; + +struct rename_info { + /* + * pairs: pairing of filenames from diffcore_rename() + * + * Index 1 and 2 correspond to sides 1 & 2 as used in + * conflict_info.stages. Index 0 unused. + */ + struct diff_queue_struct pairs[3]; + + /* + * needed_limit: value needed for inexact rename detection to run + * + * If the current rename limit wasn't high enough for inexact + * rename detection to run, this records the limit needed. Otherwise, + * this value remains 0. + */ + int needed_limit; +}; + +struct merge_options_internal { + /* + * paths: primary data structure in all of merge ort. + * + * The keys of paths: + * * are full relative paths from the toplevel of the repository + * (e.g. "drivers/firmware/raspberrypi.c"). + * * store all relevant paths in the repo, both directories and + * files (e.g. drivers, drivers/firmware would also be included) + * * these keys serve to intern all the path strings, which allows + * us to do pointer comparison on directory names instead of + * strcmp; we just have to be careful to use the interned strings. + * (Technically paths_to_free may track some strings that were + * removed from froms paths.) + * + * The values of paths: + * * either a pointer to a merged_info, or a conflict_info struct + * * merged_info contains all relevant information for a + * non-conflicted entry. + * * conflict_info contains a merged_info, plus any additional + * information about a conflict such as the higher orders stages + * involved and the names of the paths those came from (handy + * once renames get involved). + * * a path may start "conflicted" (i.e. point to a conflict_info) + * and then a later step (e.g. three-way content merge) determines + * it can be cleanly merged, at which point it'll be marked clean + * and the algorithm will ignore any data outside the contained + * merged_info for that entry + * * If an entry remains conflicted, the merged_info portion of a + * conflict_info will later be filled with whatever version of + * the file should be placed in the working directory (e.g. an + * as-merged-as-possible variation that contains conflict markers). + */ + struct strmap paths; + + /* + * conflicted: a subset of keys->values from "paths" + * + * conflicted is basically an optimization between process_entries() + * and record_conflicted_index_entries(); the latter could loop over + * ALL the entries in paths AGAIN and look for the ones that are + * still conflicted, but since process_entries() has to loop over + * all of them, it saves the ones it couldn't resolve in this strmap + * so that record_conflicted_index_entries() can iterate just the + * relevant entries. + */ + struct strmap conflicted; + + /* + * paths_to_free: additional list of strings to free + * + * If keys are removed from "paths", they are added to paths_to_free + * to ensure they are later freed. We avoid free'ing immediately since + * other places (e.g. conflict_info.pathnames[]) may still be + * referencing these paths. + */ + struct string_list paths_to_free; + + /* + * output: special messages and conflict notices for various paths + * + * This is a map of pathnames (a subset of the keys in "paths" above) + * to strbufs. It gathers various warning/conflict/notice messages + * for later processing. + */ + struct strmap output; + + /* + * renames: various data relating to rename detection + */ + struct rename_info renames; + + /* + * current_dir_name: temporary var used in collect_merge_info_callback() + * + * Used to set merged_info.directory_name; see documentation for that + * variable and the requirements placed on that field. + */ + const char *current_dir_name; + + /* call_depth: recursion level counter for merging merge bases */ + int call_depth; +}; + +struct version_info { + struct object_id oid; + unsigned short mode; +}; + +struct merged_info { + /* if is_null, ignore result. otherwise result has oid & mode */ + struct version_info result; + unsigned is_null:1; + + /* + * clean: whether the path in question is cleanly merged. + * + * see conflict_info.merged for more details. + */ + unsigned clean:1; + + /* + * basename_offset: offset of basename of path. + * + * perf optimization to avoid recomputing offset of final '/' + * character in pathname (0 if no '/' in pathname). + */ + size_t basename_offset; + + /* + * directory_name: containing directory name. + * + * Note that we assume directory_name is constructed such that + * strcmp(dir1_name, dir2_name) == 0 iff dir1_name == dir2_name, + * i.e. string equality is equivalent to pointer equality. For this + * to hold, we have to be careful setting directory_name. + */ + const char *directory_name; +}; + +struct conflict_info { + /* + * merged: the version of the path that will be written to working tree + * + * WARNING: It is critical to check merged.clean and ensure it is 0 + * before reading any conflict_info fields outside of merged. + * Allocated merge_info structs will always have clean set to 1. + * Allocated conflict_info structs will have merged.clean set to 0 + * initially. The merged.clean field is how we know if it is safe + * to access other parts of conflict_info besides merged; if a + * conflict_info's merged.clean is changed to 1, the rest of the + * algorithm is not allowed to look at anything outside of the + * merged member anymore. + */ + struct merged_info merged; + + /* oids & modes from each of the three trees for this path */ + struct version_info stages[3]; + + /* pathnames for each stage; may differ due to rename detection */ + const char *pathnames[3]; + + /* Whether this path is/was involved in a directory/file conflict */ + unsigned df_conflict:1; + + /* + * Whether this path is/was involved in a non-content conflict other + * than a directory/file conflict (e.g. rename/rename, rename/delete, + * file location based on possible directory rename). + */ + unsigned path_conflict:1; + + /* + * For filemask and dirmask, the ith bit corresponds to whether the + * ith entry is a file (filemask) or a directory (dirmask). Thus, + * filemask & dirmask is always zero, and filemask | dirmask is at + * most 7 but can be less when a path does not appear as either a + * file or a directory on at least one side of history. + * + * Note that these masks are related to enum merge_side, as the ith + * entry corresponds to side i. + * + * These values come from a traverse_trees() call; more info may be + * found looking at tree-walk.h's struct traverse_info, + * particularly the documentation above the "fn" member (note that + * filemask = mask & ~dirmask from that documentation). + */ + unsigned filemask:3; + unsigned dirmask:3; + + /* + * Optimization to track which stages match, to avoid the need to + * recompute it in multiple steps. Either 0 or at least 2 bits are + * set; if at least 2 bits are set, their corresponding stages match. + */ + unsigned match_mask:3; +}; + +/*** Function Grouping: various utility functions ***/ + +/* + * For the next three macros, see warning for conflict_info.merged. + * + * In each of the below, mi is a struct merged_info*, and ci was defined + * as a struct conflict_info* (but we need to verify ci isn't actually + * pointed at a struct merged_info*). + * + * INITIALIZE_CI: Assign ci to mi but only if it's safe; set to NULL otherwise. + * VERIFY_CI: Ensure that something we assigned to a conflict_info* is one. + * ASSIGN_AND_VERIFY_CI: Similar to VERIFY_CI but do assignment first. + */ +#define INITIALIZE_CI(ci, mi) do { \ + (ci) = (!(mi) || (mi)->clean) ? NULL : (struct conflict_info *)(mi); \ +} while (0) +#define VERIFY_CI(ci) assert(ci && !ci->merged.clean); +#define ASSIGN_AND_VERIFY_CI(ci, mi) do { \ + (ci) = (struct conflict_info *)(mi); \ + assert((ci) && !(mi)->clean); \ +} while (0) + +static void free_strmap_strings(struct strmap *map) +{ + struct hashmap_iter iter; + struct strmap_entry *entry; + + strmap_for_each_entry(map, &iter, entry) { + free((char*)entry->key); + } +} + +static void clear_or_reinit_internal_opts(struct merge_options_internal *opti, + int reinitialize) +{ + void (*strmap_func)(struct strmap *, int) = + reinitialize ? strmap_partial_clear : strmap_clear; + + /* + * We marked opti->paths with strdup_strings = 0, so that we + * wouldn't have to make another copy of the fullpath created by + * make_traverse_path from setup_path_info(). But, now that we've + * used it and have no other references to these strings, it is time + * to deallocate them. + */ + free_strmap_strings(&opti->paths); + strmap_func(&opti->paths, 1); + + /* + * All keys and values in opti->conflicted are a subset of those in + * opti->paths. We don't want to deallocate anything twice, so we + * don't free the keys and we pass 0 for free_values. + */ + strmap_func(&opti->conflicted, 0); + + /* + * opti->paths_to_free is similar to opti->paths; we created it with + * strdup_strings = 0 to avoid making _another_ copy of the fullpath + * but now that we've used it and have no other references to these + * strings, it is time to deallocate them. We do so by temporarily + * setting strdup_strings to 1. + */ + opti->paths_to_free.strdup_strings = 1; + string_list_clear(&opti->paths_to_free, 0); + opti->paths_to_free.strdup_strings = 0; + + if (!reinitialize) { + struct hashmap_iter iter; + struct strmap_entry *e; + + /* Release and free each strbuf found in output */ + strmap_for_each_entry(&opti->output, &iter, e) { + struct strbuf *sb = e->value; + strbuf_release(sb); + /* + * While strictly speaking we don't need to free(sb) + * here because we could pass free_values=1 when + * calling strmap_clear() on opti->output, that would + * require strmap_clear to do another + * strmap_for_each_entry() loop, so we just free it + * while we're iterating anyway. + */ + free(sb); + } + strmap_clear(&opti->output, 0); + } +} + +static int err(struct merge_options *opt, const char *err, ...) +{ + va_list params; + struct strbuf sb = STRBUF_INIT; + + strbuf_addstr(&sb, "error: "); + va_start(params, err); + strbuf_vaddf(&sb, err, params); + va_end(params); + + error("%s", sb.buf); + strbuf_release(&sb); + + return -1; +} + +__attribute__((format (printf, 4, 5))) +static void path_msg(struct merge_options *opt, + const char *path, + int omittable_hint, /* skippable under --remerge-diff */ + const char *fmt, ...) +{ + va_list ap; + struct strbuf *sb = strmap_get(&opt->priv->output, path); + if (!sb) { + sb = xmalloc(sizeof(*sb)); + strbuf_init(sb, 0); + strmap_put(&opt->priv->output, path, sb); + } + + va_start(ap, fmt); + strbuf_vaddf(sb, fmt, ap); + va_end(ap); + + strbuf_addch(sb, '\n'); +} + +/*** Function Grouping: functions related to collect_merge_info() ***/ + +static void setup_path_info(struct merge_options *opt, + struct string_list_item *result, + const char *current_dir_name, + int current_dir_name_len, + char *fullpath, /* we'll take over ownership */ + struct name_entry *names, + struct name_entry *merged_version, + unsigned is_null, /* boolean */ + unsigned df_conflict, /* boolean */ + unsigned filemask, + unsigned dirmask, + int resolved /* boolean */) +{ + /* result->util is void*, so mi is a convenience typed variable */ + struct merged_info *mi; + + assert(!is_null || resolved); + assert(!df_conflict || !resolved); /* df_conflict implies !resolved */ + assert(resolved == (merged_version != NULL)); + + mi = xcalloc(1, resolved ? sizeof(struct merged_info) : + sizeof(struct conflict_info)); + mi->directory_name = current_dir_name; + mi->basename_offset = current_dir_name_len; + mi->clean = !!resolved; + if (resolved) { + mi->result.mode = merged_version->mode; + oidcpy(&mi->result.oid, &merged_version->oid); + mi->is_null = !!is_null; + } else { + int i; + struct conflict_info *ci; + + ASSIGN_AND_VERIFY_CI(ci, mi); + for (i = MERGE_BASE; i <= MERGE_SIDE2; i++) { + ci->pathnames[i] = fullpath; + ci->stages[i].mode = names[i].mode; + oidcpy(&ci->stages[i].oid, &names[i].oid); + } + ci->filemask = filemask; + ci->dirmask = dirmask; + ci->df_conflict = !!df_conflict; + if (dirmask) + /* + * Assume is_null for now, but if we have entries + * under the directory then when it is complete in + * write_completed_directory() it'll update this. + * Also, for D/F conflicts, we have to handle the + * directory first, then clear this bit and process + * the file to see how it is handled -- that occurs + * near the top of process_entry(). + */ + mi->is_null = 1; + } + strmap_put(&opt->priv->paths, fullpath, mi); + result->string = fullpath; + result->util = mi; +} + +static int collect_merge_info_callback(int n, + unsigned long mask, + unsigned long dirmask, + struct name_entry *names, + struct traverse_info *info) +{ + /* + * n is 3. Always. + * common ancestor (mbase) has mask 1, and stored in index 0 of names + * head of side 1 (side1) has mask 2, and stored in index 1 of names + * head of side 2 (side2) has mask 4, and stored in index 2 of names + */ + struct merge_options *opt = info->data; + struct merge_options_internal *opti = opt->priv; + struct string_list_item pi; /* Path Info */ + struct conflict_info *ci; /* typed alias to pi.util (which is void*) */ + struct name_entry *p; + size_t len; + char *fullpath; + const char *dirname = opti->current_dir_name; + unsigned filemask = mask & ~dirmask; + unsigned match_mask = 0; /* will be updated below */ + unsigned mbase_null = !(mask & 1); + unsigned side1_null = !(mask & 2); + unsigned side2_null = !(mask & 4); + unsigned side1_matches_mbase = (!side1_null && !mbase_null && + names[0].mode == names[1].mode && + oideq(&names[0].oid, &names[1].oid)); + unsigned side2_matches_mbase = (!side2_null && !mbase_null && + names[0].mode == names[2].mode && + oideq(&names[0].oid, &names[2].oid)); + unsigned sides_match = (!side1_null && !side2_null && + names[1].mode == names[2].mode && + oideq(&names[1].oid, &names[2].oid)); + + /* + * Note: When a path is a file on one side of history and a directory + * in another, we have a directory/file conflict. In such cases, if + * the conflict doesn't resolve from renames and deletions, then we + * always leave directories where they are and move files out of the + * way. Thus, while struct conflict_info has a df_conflict field to + * track such conflicts, we ignore that field for any directories at + * a path and only pay attention to it for files at the given path. + * The fact that we leave directories were they are also means that + * we do not need to worry about getting additional df_conflict + * information propagated from parent directories down to children + * (unlike, say traverse_trees_recursive() in unpack-trees.c, which + * sets a newinfo.df_conflicts field specifically to propagate it). + */ + unsigned df_conflict = (filemask != 0) && (dirmask != 0); + + /* n = 3 is a fundamental assumption. */ + if (n != 3) + BUG("Called collect_merge_info_callback wrong"); + + /* + * A bunch of sanity checks verifying that traverse_trees() calls + * us the way I expect. Could just remove these at some point, + * though maybe they are helpful to future code readers. + */ + assert(mbase_null == is_null_oid(&names[0].oid)); + assert(side1_null == is_null_oid(&names[1].oid)); + assert(side2_null == is_null_oid(&names[2].oid)); + assert(!mbase_null || !side1_null || !side2_null); + assert(mask > 0 && mask < 8); + + /* Determine match_mask */ + if (side1_matches_mbase) + match_mask = (side2_matches_mbase ? 7 : 3); + else if (side2_matches_mbase) + match_mask = 5; + else if (sides_match) + match_mask = 6; + + /* + * Get the name of the relevant filepath, which we'll pass to + * setup_path_info() for tracking. + */ + p = names; + while (!p->mode) + p++; + len = traverse_path_len(info, p->pathlen); + + /* +1 in both of the following lines to include the NUL byte */ + fullpath = xmalloc(len + 1); + make_traverse_path(fullpath, len + 1, info, p->path, p->pathlen); + + /* + * If mbase, side1, and side2 all match, we can resolve early. Even + * if these are trees, there will be no renames or anything + * underneath. + */ + if (side1_matches_mbase && side2_matches_mbase) { + /* mbase, side1, & side2 all match; use mbase as resolution */ + setup_path_info(opt, &pi, dirname, info->pathlen, fullpath, + names, names+0, mbase_null, 0, + filemask, dirmask, 1); + return mask; + } + + /* + * Record information about the path so we can resolve later in + * process_entries. + */ + setup_path_info(opt, &pi, dirname, info->pathlen, fullpath, + names, NULL, 0, df_conflict, filemask, dirmask, 0); + + ci = pi.util; + VERIFY_CI(ci); + ci->match_mask = match_mask; + + /* If dirmask, recurse into subdirectories */ + if (dirmask) { + struct traverse_info newinfo; + struct tree_desc t[3]; + void *buf[3] = {NULL, NULL, NULL}; + const char *original_dir_name; + int i, ret; + + ci->match_mask &= filemask; + newinfo = *info; + newinfo.prev = info; + newinfo.name = p->path; + newinfo.namelen = p->pathlen; + newinfo.pathlen = st_add3(newinfo.pathlen, p->pathlen, 1); + /* + * If this directory we are about to recurse into cared about + * its parent directory (the current directory) having a D/F + * conflict, then we'd propagate the masks in this way: + * newinfo.df_conflicts |= (mask & ~dirmask); + * But we don't worry about propagating D/F conflicts. (See + * comment near setting of local df_conflict variable near + * the beginning of this function). + */ + + for (i = MERGE_BASE; i <= MERGE_SIDE2; i++) { + if (i == 1 && side1_matches_mbase) + t[1] = t[0]; + else if (i == 2 && side2_matches_mbase) + t[2] = t[0]; + else if (i == 2 && sides_match) + t[2] = t[1]; + else { + const struct object_id *oid = NULL; + if (dirmask & 1) + oid = &names[i].oid; + buf[i] = fill_tree_descriptor(opt->repo, + t + i, oid); + } + dirmask >>= 1; + } + + original_dir_name = opti->current_dir_name; + opti->current_dir_name = pi.string; + ret = traverse_trees(NULL, 3, t, &newinfo); + opti->current_dir_name = original_dir_name; + + for (i = MERGE_BASE; i <= MERGE_SIDE2; i++) + free(buf[i]); + + if (ret < 0) + return -1; + } + + return mask; +} + +static int collect_merge_info(struct merge_options *opt, + struct tree *merge_base, + struct tree *side1, + struct tree *side2) +{ + int ret; + struct tree_desc t[3]; + struct traverse_info info; + const char *toplevel_dir_placeholder = ""; + + opt->priv->current_dir_name = toplevel_dir_placeholder; + setup_traverse_info(&info, toplevel_dir_placeholder); + info.fn = collect_merge_info_callback; + info.data = opt; + info.show_all_errors = 1; + + parse_tree(merge_base); + parse_tree(side1); + parse_tree(side2); + init_tree_desc(t + 0, merge_base->buffer, merge_base->size); + init_tree_desc(t + 1, side1->buffer, side1->size); + init_tree_desc(t + 2, side2->buffer, side2->size); + + ret = traverse_trees(NULL, 3, t, &info); + + return ret; +} + +/*** Function Grouping: functions related to threeway content merges ***/ + +static int handle_content_merge(struct merge_options *opt, + const char *path, + const struct version_info *o, + const struct version_info *a, + const struct version_info *b, + const char *pathnames[3], + const int extra_marker_size, + struct version_info *result) +{ + die("Not yet implemented"); +} + +/*** Function Grouping: functions related to detect_and_process_renames(), *** + *** which are split into directory and regular rename detection sections. ***/ + +/*** Function Grouping: functions related to directory rename detection ***/ + +/*** Function Grouping: functions related to regular rename detection ***/ + +static int process_renames(struct merge_options *opt, + struct diff_queue_struct *renames) +{ + int clean_merge = 1, i; + + for (i = 0; i < renames->nr; ++i) { + const char *oldpath = NULL, *newpath; + struct diff_filepair *pair = renames->queue[i]; + struct conflict_info *oldinfo = NULL, *newinfo = NULL; + struct strmap_entry *old_ent, *new_ent; + unsigned int old_sidemask; + int target_index, other_source_index; + int source_deleted, collision, type_changed; + const char *rename_branch = NULL, *delete_branch = NULL; + + old_ent = strmap_get_entry(&opt->priv->paths, pair->one->path); + oldpath = old_ent->key; + oldinfo = old_ent->value; + + new_ent = strmap_get_entry(&opt->priv->paths, pair->two->path); + newpath = new_ent->key; + newinfo = new_ent->value; + + /* + * diff_filepairs have copies of pathnames, thus we have to + * use standard 'strcmp()' (negated) instead of '=='. + */ + if (i + 1 < renames->nr && + !strcmp(oldpath, renames->queue[i+1]->one->path)) { + /* Handle rename/rename(1to2) or rename/rename(1to1) */ + const char *pathnames[3]; + struct version_info merged; + struct conflict_info *base, *side1, *side2; + unsigned was_binary_blob = 0; + + pathnames[0] = oldpath; + pathnames[1] = newpath; + pathnames[2] = renames->queue[i+1]->two->path; + + base = strmap_get(&opt->priv->paths, pathnames[0]); + side1 = strmap_get(&opt->priv->paths, pathnames[1]); + side2 = strmap_get(&opt->priv->paths, pathnames[2]); + + VERIFY_CI(base); + VERIFY_CI(side1); + VERIFY_CI(side2); + + if (!strcmp(pathnames[1], pathnames[2])) { + /* Both sides renamed the same way */ + assert(side1 == side2); + memcpy(&side1->stages[0], &base->stages[0], + sizeof(merged)); + side1->filemask |= (1 << MERGE_BASE); + /* Mark base as resolved by removal */ + base->merged.is_null = 1; + base->merged.clean = 1; + + /* We handled both renames, i.e. i+1 handled */ + i++; + /* Move to next rename */ + continue; + } + + /* This is a rename/rename(1to2) */ + clean_merge = handle_content_merge(opt, + pair->one->path, + &base->stages[0], + &side1->stages[1], + &side2->stages[2], + pathnames, + 1 + 2 * opt->priv->call_depth, + &merged); + if (!clean_merge && + merged.mode == side1->stages[1].mode && + oideq(&merged.oid, &side1->stages[1].oid)) + was_binary_blob = 1; + memcpy(&side1->stages[1], &merged, sizeof(merged)); + if (was_binary_blob) { + /* + * Getting here means we were attempting to + * merge a binary blob. + * + * Since we can't merge binaries, + * handle_content_merge() just takes one + * side. But we don't want to copy the + * contents of one side to both paths. We + * used the contents of side1 above for + * side1->stages, let's use the contents of + * side2 for side2->stages below. + */ + oidcpy(&merged.oid, &side2->stages[2].oid); + merged.mode = side2->stages[2].mode; + } + memcpy(&side2->stages[2], &merged, sizeof(merged)); + + side1->path_conflict = 1; + side2->path_conflict = 1; + /* + * TODO: For renames we normally remove the path at the + * old name. It would thus seem consistent to do the + * same for rename/rename(1to2) cases, but we haven't + * done so traditionally and a number of the regression + * tests now encode an expectation that the file is + * left there at stage 1. If we ever decide to change + * this, add the following two lines here: + * base->merged.is_null = 1; + * base->merged.clean = 1; + * and remove the setting of base->path_conflict to 1. + */ + base->path_conflict = 1; + path_msg(opt, oldpath, 0, + _("CONFLICT (rename/rename): %s renamed to " + "%s in %s and to %s in %s."), + pathnames[0], + pathnames[1], opt->branch1, + pathnames[2], opt->branch2); + + i++; /* We handled both renames, i.e. i+1 handled */ + continue; + } + + VERIFY_CI(oldinfo); + VERIFY_CI(newinfo); + target_index = pair->score; /* from collect_renames() */ + assert(target_index == 1 || target_index == 2); + other_source_index = 3 - target_index; + old_sidemask = (1 << other_source_index); /* 2 or 4 */ + source_deleted = (oldinfo->filemask == 1); + collision = ((newinfo->filemask & old_sidemask) != 0); + type_changed = !source_deleted && + (S_ISREG(oldinfo->stages[other_source_index].mode) != + S_ISREG(newinfo->stages[target_index].mode)); + if (type_changed && collision) { + /* + * special handling so later blocks can handle this... + * + * if type_changed && collision are both true, then this + * was really a double rename, but one side wasn't + * detected due to lack of break detection. I.e. + * something like + * orig: has normal file 'foo' + * side1: renames 'foo' to 'bar', adds 'foo' symlink + * side2: renames 'foo' to 'bar' + * In this case, the foo->bar rename on side1 won't be + * detected because the new symlink named 'foo' is + * there and we don't do break detection. But we detect + * this here because we don't want to merge the content + * of the foo symlink with the foo->bar file, so we + * have some logic to handle this special case. The + * easiest way to do that is make 'bar' on side1 not + * be considered a colliding file but the other part + * of a normal rename. If the file is very different, + * well we're going to get content merge conflicts + * anyway so it doesn't hurt. And if the colliding + * file also has a different type, that'll be handled + * by the content merge logic in process_entry() too. + * + * See also t6430, 'rename vs. rename/symlink' + */ + collision = 0; + } + if (source_deleted) { + if (target_index == 1) { + rename_branch = opt->branch1; + delete_branch = opt->branch2; + } else { + rename_branch = opt->branch2; + delete_branch = opt->branch1; + } + } + + assert(source_deleted || oldinfo->filemask & old_sidemask); + + /* Need to check for special types of rename conflicts... */ + if (collision && !source_deleted) { + /* collision: rename/add or rename/rename(2to1) */ + const char *pathnames[3]; + struct version_info merged; + + struct conflict_info *base, *side1, *side2; + unsigned clean; + + pathnames[0] = oldpath; + pathnames[other_source_index] = oldpath; + pathnames[target_index] = newpath; + + base = strmap_get(&opt->priv->paths, pathnames[0]); + side1 = strmap_get(&opt->priv->paths, pathnames[1]); + side2 = strmap_get(&opt->priv->paths, pathnames[2]); + + VERIFY_CI(base); + VERIFY_CI(side1); + VERIFY_CI(side2); + + clean = handle_content_merge(opt, pair->one->path, + &base->stages[0], + &side1->stages[1], + &side2->stages[2], + pathnames, + 1 + 2 * opt->priv->call_depth, + &merged); + + memcpy(&newinfo->stages[target_index], &merged, + sizeof(merged)); + if (!clean) { + path_msg(opt, newpath, 0, + _("CONFLICT (rename involved in " + "collision): rename of %s -> %s has " + "content conflicts AND collides " + "with another path; this may result " + "in nested conflict markers."), + oldpath, newpath); + } + } else if (collision && source_deleted) { + /* + * rename/add/delete or rename/rename(2to1)/delete: + * since oldpath was deleted on the side that didn't + * do the rename, there's not much of a content merge + * we can do for the rename. oldinfo->merged.is_null + * was already set, so we just leave things as-is so + * they look like an add/add conflict. + */ + + newinfo->path_conflict = 1; + path_msg(opt, newpath, 0, + _("CONFLICT (rename/delete): %s renamed " + "to %s in %s, but deleted in %s."), + oldpath, newpath, rename_branch, delete_branch); + } else { + /* + * a few different cases...start by copying the + * existing stage(s) from oldinfo over the newinfo + * and update the pathname(s). + */ + memcpy(&newinfo->stages[0], &oldinfo->stages[0], + sizeof(newinfo->stages[0])); + newinfo->filemask |= (1 << MERGE_BASE); + newinfo->pathnames[0] = oldpath; + if (type_changed) { + /* rename vs. typechange */ + /* Mark the original as resolved by removal */ + memcpy(&oldinfo->stages[0].oid, &null_oid, + sizeof(oldinfo->stages[0].oid)); + oldinfo->stages[0].mode = 0; + oldinfo->filemask &= 0x06; + } else if (source_deleted) { + /* rename/delete */ + newinfo->path_conflict = 1; + path_msg(opt, newpath, 0, + _("CONFLICT (rename/delete): %s renamed" + " to %s in %s, but deleted in %s."), + oldpath, newpath, + rename_branch, delete_branch); + } else { + /* normal rename */ + memcpy(&newinfo->stages[other_source_index], + &oldinfo->stages[other_source_index], + sizeof(newinfo->stages[0])); + newinfo->filemask |= (1 << other_source_index); + newinfo->pathnames[other_source_index] = oldpath; + } + } + + if (!type_changed) { + /* Mark the original as resolved by removal */ + oldinfo->merged.is_null = 1; + oldinfo->merged.clean = 1; + } + + } + + return clean_merge; +} + +static int compare_pairs(const void *a_, const void *b_) +{ + const struct diff_filepair *a = *((const struct diff_filepair **)a_); + const struct diff_filepair *b = *((const struct diff_filepair **)b_); + + return strcmp(a->one->path, b->one->path); +} + +/* Call diffcore_rename() to compute which files have changed on given side */ +static void detect_regular_renames(struct merge_options *opt, + struct tree *merge_base, + struct tree *side, + unsigned side_index) +{ + struct diff_options diff_opts; + struct rename_info *renames = &opt->priv->renames; + + repo_diff_setup(opt->repo, &diff_opts); + diff_opts.flags.recursive = 1; + diff_opts.flags.rename_empty = 0; + diff_opts.detect_rename = DIFF_DETECT_RENAME; + diff_opts.rename_limit = opt->rename_limit; + if (opt->rename_limit <= 0) + diff_opts.rename_limit = 1000; + diff_opts.rename_score = opt->rename_score; + diff_opts.show_rename_progress = opt->show_rename_progress; + diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT; + diff_setup_done(&diff_opts); + diff_tree_oid(&merge_base->object.oid, &side->object.oid, "", + &diff_opts); + diffcore_std(&diff_opts); + + if (diff_opts.needed_rename_limit > renames->needed_limit) + renames->needed_limit = diff_opts.needed_rename_limit; + + renames->pairs[side_index] = diff_queued_diff; + + diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT; + diff_queued_diff.nr = 0; + diff_queued_diff.queue = NULL; + diff_flush(&diff_opts); +} + +/* + * Get information of all renames which occurred in 'side_pairs', discarding + * non-renames. + */ +static int collect_renames(struct merge_options *opt, + struct diff_queue_struct *result, + unsigned side_index) +{ + int i, clean = 1; + struct diff_queue_struct *side_pairs; + struct rename_info *renames = &opt->priv->renames; + + side_pairs = &renames->pairs[side_index]; + + for (i = 0; i < side_pairs->nr; ++i) { + struct diff_filepair *p = side_pairs->queue[i]; + + if (p->status != 'R') { + diff_free_filepair(p); + continue; + } + + /* + * p->score comes back from diffcore_rename_extended() with + * the similarity of the renamed file. The similarity is + * was used to determine that the two files were related + * and are a rename, which we have already used, but beyond + * that we have no use for the similarity. So p->score is + * now irrelevant. However, process_renames() will need to + * know which side of the merge this rename was associated + * with, so overwrite p->score with that value. + */ + p->score = side_index; + result->queue[result->nr++] = p; + } + + return clean; +} + +static int detect_and_process_renames(struct merge_options *opt, + struct tree *merge_base, + struct tree *side1, + struct tree *side2) +{ + struct diff_queue_struct combined; + struct rename_info *renames = &opt->priv->renames; + int s, clean = 1; + + memset(&combined, 0, sizeof(combined)); + + detect_regular_renames(opt, merge_base, side1, MERGE_SIDE1); + detect_regular_renames(opt, merge_base, side2, MERGE_SIDE2); + + ALLOC_GROW(combined.queue, + renames->pairs[1].nr + renames->pairs[2].nr, + combined.alloc); + clean &= collect_renames(opt, &combined, MERGE_SIDE1); + clean &= collect_renames(opt, &combined, MERGE_SIDE2); + QSORT(combined.queue, combined.nr, compare_pairs); + + clean &= process_renames(opt, &combined); + + /* Free memory for renames->pairs[] and combined */ + for (s = MERGE_SIDE1; s <= MERGE_SIDE2; s++) { + free(renames->pairs[s].queue); + DIFF_QUEUE_CLEAR(&renames->pairs[s]); + } + if (combined.nr) { + int i; + for (i = 0; i < combined.nr; i++) + diff_free_filepair(combined.queue[i]); + free(combined.queue); + } + + return clean; +} + +/*** Function Grouping: functions related to process_entries() ***/ + +static int string_list_df_name_compare(const char *one, const char *two) +{ + int onelen = strlen(one); + int twolen = strlen(two); + /* + * Here we only care that entries for D/F conflicts are + * adjacent, in particular with the file of the D/F conflict + * appearing before files below the corresponding directory. + * The order of the rest of the list is irrelevant for us. + * + * To achieve this, we sort with df_name_compare and provide + * the mode S_IFDIR so that D/F conflicts will sort correctly. + * We use the mode S_IFDIR for everything else for simplicity, + * since in other cases any changes in their order due to + * sorting cause no problems for us. + */ + int cmp = df_name_compare(one, onelen, S_IFDIR, + two, twolen, S_IFDIR); + /* + * Now that 'foo' and 'foo/bar' compare equal, we have to make sure + * that 'foo' comes before 'foo/bar'. + */ + if (cmp) + return cmp; + return onelen - twolen; +} + +struct directory_versions { + /* + * versions: list of (basename -> version_info) + * + * The basenames are in reverse lexicographic order of full pathnames, + * as processed in process_entries(). This puts all entries within + * a directory together, and covers the directory itself after + * everything within it, allowing us to write subtrees before needing + * to record information for the tree itself. + */ + struct string_list versions; + + /* + * offsets: list of (full relative path directories -> integer offsets) + * + * Since versions contains basenames from files in multiple different + * directories, we need to know which entries in versions correspond + * to which directories. Values of e.g. + * "" 0 + * src 2 + * src/moduleA 5 + * Would mean that entries 0-1 of versions are files in the toplevel + * directory, entries 2-4 are files under src/, and the remaining + * entries starting at index 5 are files under src/moduleA/. + */ + struct string_list offsets; + + /* + * last_directory: directory that previously processed file found in + * + * last_directory starts NULL, but records the directory in which the + * previous file was found within. As soon as + * directory(current_file) != last_directory + * then we need to start updating accounting in versions & offsets. + * Note that last_directory is always the last path in "offsets" (or + * NULL if "offsets" is empty) so this exists just for quick access. + */ + const char *last_directory; + + /* last_directory_len: cached computation of strlen(last_directory) */ + unsigned last_directory_len; +}; + +static int tree_entry_order(const void *a_, const void *b_) +{ + const struct string_list_item *a = a_; + const struct string_list_item *b = b_; + + const struct merged_info *ami = a->util; + const struct merged_info *bmi = b->util; + return base_name_compare(a->string, strlen(a->string), ami->result.mode, + b->string, strlen(b->string), bmi->result.mode); +} + +static void write_tree(struct object_id *result_oid, + struct string_list *versions, + unsigned int offset, + size_t hash_size) +{ + size_t maxlen = 0, extra; + unsigned int nr = versions->nr - offset; + struct strbuf buf = STRBUF_INIT; + struct string_list relevant_entries = STRING_LIST_INIT_NODUP; + int i; + + /* + * We want to sort the last (versions->nr-offset) entries in versions. + * Do so by abusing the string_list API a bit: make another string_list + * that contains just those entries and then sort them. + * + * We won't use relevant_entries again and will let it just pop off the + * stack, so there won't be allocation worries or anything. + */ + relevant_entries.items = versions->items + offset; + relevant_entries.nr = versions->nr - offset; + QSORT(relevant_entries.items, relevant_entries.nr, tree_entry_order); + + /* Pre-allocate some space in buf */ + extra = hash_size + 8; /* 8: 6 for mode, 1 for space, 1 for NUL char */ + for (i = 0; i < nr; i++) { + maxlen += strlen(versions->items[offset+i].string) + extra; + } + strbuf_grow(&buf, maxlen); + + /* Write each entry out to buf */ + for (i = 0; i < nr; i++) { + struct merged_info *mi = versions->items[offset+i].util; + struct version_info *ri = &mi->result; + strbuf_addf(&buf, "%o %s%c", + ri->mode, + versions->items[offset+i].string, '\0'); + strbuf_add(&buf, ri->oid.hash, hash_size); + } + + /* Write this object file out, and record in result_oid */ + write_object_file(buf.buf, buf.len, tree_type, result_oid); + strbuf_release(&buf); +} + +static void record_entry_for_tree(struct directory_versions *dir_metadata, + const char *path, + struct merged_info *mi) +{ + const char *basename; + + if (mi->is_null) + /* nothing to record */ + return; + + basename = path + mi->basename_offset; + assert(strchr(basename, '/') == NULL); + string_list_append(&dir_metadata->versions, + basename)->util = &mi->result; +} + +static void write_completed_directory(struct merge_options *opt, + const char *new_directory_name, + struct directory_versions *info) +{ + const char *prev_dir; + struct merged_info *dir_info = NULL; + unsigned int offset; + + /* + * Some explanation of info->versions and info->offsets... + * + * process_entries() iterates over all relevant files AND + * directories in reverse lexicographic order, and calls this + * function. Thus, an example of the paths that process_entries() + * could operate on (along with the directories for those paths + * being shown) is: + * + * xtract.c "" + * tokens.txt "" + * src/moduleB/umm.c src/moduleB + * src/moduleB/stuff.h src/moduleB + * src/moduleB/baz.c src/moduleB + * src/moduleB src + * src/moduleA/foo.c src/moduleA + * src/moduleA/bar.c src/moduleA + * src/moduleA src + * src "" + * Makefile "" + * + * info->versions: + * + * always contains the unprocessed entries and their + * version_info information. For example, after the first five + * entries above, info->versions would be: + * + * xtract.c <xtract.c's version_info> + * token.txt <token.txt's version_info> + * umm.c <src/moduleB/umm.c's version_info> + * stuff.h <src/moduleB/stuff.h's version_info> + * baz.c <src/moduleB/baz.c's version_info> + * + * Once a subdirectory is completed we remove the entries in + * that subdirectory from info->versions, writing it as a tree + * (write_tree()). Thus, as soon as we get to src/moduleB, + * info->versions would be updated to + * + * xtract.c <xtract.c's version_info> + * token.txt <token.txt's version_info> + * moduleB <src/moduleB's version_info> + * + * info->offsets: + * + * helps us track which entries in info->versions correspond to + * which directories. When we are N directories deep (e.g. 4 + * for src/modA/submod/subdir/), we have up to N+1 unprocessed + * directories (+1 because of toplevel dir). Corresponding to + * the info->versions example above, after processing five entries + * info->offsets will be: + * + * "" 0 + * src/moduleB 2 + * + * which is used to know that xtract.c & token.txt are from the + * toplevel dirctory, while umm.c & stuff.h & baz.c are from the + * src/moduleB directory. Again, following the example above, + * once we need to process src/moduleB, then info->offsets is + * updated to + * + * "" 0 + * src 2 + * + * which says that moduleB (and only moduleB so far) is in the + * src directory. + * + * One unique thing to note about info->offsets here is that + * "src" was not added to info->offsets until there was a path + * (a file OR directory) immediately below src/ that got + * processed. + * + * Since process_entry() just appends new entries to info->versions, + * write_completed_directory() only needs to do work if the next path + * is in a directory that is different than the last directory found + * in info->offsets. + */ + + /* + * If we are working with the same directory as the last entry, there + * is no work to do. (See comments above the directory_name member of + * struct merged_info for why we can use pointer comparison instead of + * strcmp here.) + */ + if (new_directory_name == info->last_directory) + return; + + /* + * If we are just starting (last_directory is NULL), or last_directory + * is a prefix of the current directory, then we can just update + * info->offsets to record the offset where we started this directory + * and update last_directory to have quick access to it. + */ + if (info->last_directory == NULL || + !strncmp(new_directory_name, info->last_directory, + info->last_directory_len)) { + uintptr_t offset = info->versions.nr; + + info->last_directory = new_directory_name; + info->last_directory_len = strlen(info->last_directory); + /* + * Record the offset into info->versions where we will + * start recording basenames of paths found within + * new_directory_name. + */ + string_list_append(&info->offsets, + info->last_directory)->util = (void*)offset; + return; + } + + /* + * The next entry that will be processed will be within + * new_directory_name. Since at this point we know that + * new_directory_name is within a different directory than + * info->last_directory, we have all entries for info->last_directory + * in info->versions and we need to create a tree object for them. + */ + dir_info = strmap_get(&opt->priv->paths, info->last_directory); + assert(dir_info); + offset = (uintptr_t)info->offsets.items[info->offsets.nr-1].util; + if (offset == info->versions.nr) { + /* + * Actually, we don't need to create a tree object in this + * case. Whenever all files within a directory disappear + * during the merge (e.g. unmodified on one side and + * deleted on the other, or files were renamed elsewhere), + * then we get here and the directory itself needs to be + * omitted from its parent tree as well. + */ + dir_info->is_null = 1; + } else { + /* + * Write out the tree to the git object directory, and also + * record the mode and oid in dir_info->result. + */ + dir_info->is_null = 0; + dir_info->result.mode = S_IFDIR; + write_tree(&dir_info->result.oid, &info->versions, offset, + opt->repo->hash_algo->rawsz); + } + + /* + * We've now used several entries from info->versions and one entry + * from info->offsets, so we get rid of those values. + */ + info->offsets.nr--; + info->versions.nr = offset; + + /* + * Now we've taken care of the completed directory, but we need to + * prepare things since future entries will be in + * new_directory_name. (In particular, process_entry() will be + * appending new entries to info->versions.) So, we need to make + * sure new_directory_name is the last entry in info->offsets. + */ + prev_dir = info->offsets.nr == 0 ? NULL : + info->offsets.items[info->offsets.nr-1].string; + if (new_directory_name != prev_dir) { + uintptr_t c = info->versions.nr; + string_list_append(&info->offsets, + new_directory_name)->util = (void*)c; + } + + /* And, of course, we need to update last_directory to match. */ + info->last_directory = new_directory_name; + info->last_directory_len = strlen(info->last_directory); +} + +/* Per entry merge function */ +static void process_entry(struct merge_options *opt, + const char *path, + struct conflict_info *ci, + struct directory_versions *dir_metadata) +{ + VERIFY_CI(ci); + assert(ci->filemask >= 0 && ci->filemask <= 7); + /* ci->match_mask == 7 was handled in collect_merge_info_callback() */ + assert(ci->match_mask == 0 || ci->match_mask == 3 || + ci->match_mask == 5 || ci->match_mask == 6); + + if (ci->dirmask) { + record_entry_for_tree(dir_metadata, path, &ci->merged); + if (ci->filemask == 0) + /* nothing else to handle */ + return; + assert(ci->df_conflict); + } + + if (ci->df_conflict) { + die("Not yet implemented."); + } + + /* + * NOTE: Below there is a long switch-like if-elseif-elseif... block + * which the code goes through even for the df_conflict cases + * above. Well, it will once we don't die-not-implemented above. + */ + if (ci->match_mask) { + ci->merged.clean = 1; + if (ci->match_mask == 6) { + /* stages[1] == stages[2] */ + ci->merged.result.mode = ci->stages[1].mode; + oidcpy(&ci->merged.result.oid, &ci->stages[1].oid); + } else { + /* determine the mask of the side that didn't match */ + unsigned int othermask = 7 & ~ci->match_mask; + int side = (othermask == 4) ? 2 : 1; + + ci->merged.result.mode = ci->stages[side].mode; + ci->merged.is_null = !ci->merged.result.mode; + oidcpy(&ci->merged.result.oid, &ci->stages[side].oid); + + assert(othermask == 2 || othermask == 4); + assert(ci->merged.is_null == + (ci->filemask == ci->match_mask)); + } + } else if (ci->filemask >= 6 && + (S_IFMT & ci->stages[1].mode) != + (S_IFMT & ci->stages[2].mode)) { + /* + * Two different items from (file/submodule/symlink) + */ + die("Not yet implemented."); + } else if (ci->filemask >= 6) { + /* + * TODO: Needs a two-way or three-way content merge, but we're + * just being lazy and copying the version from HEAD and + * leaving it as conflicted. + */ + ci->merged.clean = 0; + ci->merged.result.mode = ci->stages[1].mode; + oidcpy(&ci->merged.result.oid, &ci->stages[1].oid); + /* When we fix above, we'll call handle_content_merge() */ + (void)handle_content_merge; + } else if (ci->filemask == 3 || ci->filemask == 5) { + /* Modify/delete */ + const char *modify_branch, *delete_branch; + int side = (ci->filemask == 5) ? 2 : 1; + int index = opt->priv->call_depth ? 0 : side; + + ci->merged.result.mode = ci->stages[index].mode; + oidcpy(&ci->merged.result.oid, &ci->stages[index].oid); + ci->merged.clean = 0; + + modify_branch = (side == 1) ? opt->branch1 : opt->branch2; + delete_branch = (side == 1) ? opt->branch2 : opt->branch1; + + if (ci->path_conflict && + oideq(&ci->stages[0].oid, &ci->stages[side].oid)) { + /* + * This came from a rename/delete; no action to take, + * but avoid printing "modify/delete" conflict notice + * since the contents were not modified. + */ + } else { + path_msg(opt, path, 0, + _("CONFLICT (modify/delete): %s deleted in %s " + "and modified in %s. Version %s of %s left " + "in tree."), + path, delete_branch, modify_branch, + modify_branch, path); + } + } else if (ci->filemask == 2 || ci->filemask == 4) { + /* Added on one side */ + int side = (ci->filemask == 4) ? 2 : 1; + ci->merged.result.mode = ci->stages[side].mode; + oidcpy(&ci->merged.result.oid, &ci->stages[side].oid); + ci->merged.clean = !ci->df_conflict && !ci->path_conflict; + } else if (ci->filemask == 1) { + /* Deleted on both sides */ + ci->merged.is_null = 1; + ci->merged.result.mode = 0; + oidcpy(&ci->merged.result.oid, &null_oid); + ci->merged.clean = !ci->path_conflict; + } + + /* + * If still conflicted, record it separately. This allows us to later + * iterate over just conflicted entries when updating the index instead + * of iterating over all entries. + */ + if (!ci->merged.clean) + strmap_put(&opt->priv->conflicted, path, ci); + record_entry_for_tree(dir_metadata, path, &ci->merged); +} + +static void process_entries(struct merge_options *opt, + struct object_id *result_oid) +{ + struct hashmap_iter iter; + struct strmap_entry *e; + struct string_list plist = STRING_LIST_INIT_NODUP; + struct string_list_item *entry; + struct directory_versions dir_metadata = { STRING_LIST_INIT_NODUP, + STRING_LIST_INIT_NODUP, + NULL, 0 }; + + if (strmap_empty(&opt->priv->paths)) { + oidcpy(result_oid, opt->repo->hash_algo->empty_tree); + return; + } + + /* Hack to pre-allocate plist to the desired size */ + ALLOC_GROW(plist.items, strmap_get_size(&opt->priv->paths), plist.alloc); + + /* Put every entry from paths into plist, then sort */ + strmap_for_each_entry(&opt->priv->paths, &iter, e) { + string_list_append(&plist, e->key)->util = e->value; + } + plist.cmp = string_list_df_name_compare; + string_list_sort(&plist); + + /* + * Iterate over the items in reverse order, so we can handle paths + * below a directory before needing to handle the directory itself. + * + * This allows us to write subtrees before we need to write trees, + * and it also enables sane handling of directory/file conflicts + * (because it allows us to know whether the directory is still in + * the way when it is time to process the file at the same path). + */ + for (entry = &plist.items[plist.nr-1]; entry >= plist.items; --entry) { + char *path = entry->string; + /* + * NOTE: mi may actually be a pointer to a conflict_info, but + * we have to check mi->clean first to see if it's safe to + * reassign to such a pointer type. + */ + struct merged_info *mi = entry->util; + + write_completed_directory(opt, mi->directory_name, + &dir_metadata); + if (mi->clean) + record_entry_for_tree(&dir_metadata, path, mi); + else { + struct conflict_info *ci = (struct conflict_info *)mi; + process_entry(opt, path, ci, &dir_metadata); + } + } + + if (dir_metadata.offsets.nr != 1 || + (uintptr_t)dir_metadata.offsets.items[0].util != 0) { + printf("dir_metadata.offsets.nr = %d (should be 1)\n", + dir_metadata.offsets.nr); + printf("dir_metadata.offsets.items[0].util = %u (should be 0)\n", + (unsigned)(uintptr_t)dir_metadata.offsets.items[0].util); + fflush(stdout); + BUG("dir_metadata accounting completely off; shouldn't happen"); + } + write_tree(result_oid, &dir_metadata.versions, 0, + opt->repo->hash_algo->rawsz); + string_list_clear(&plist, 0); + string_list_clear(&dir_metadata.versions, 0); + string_list_clear(&dir_metadata.offsets, 0); +} + +/*** Function Grouping: functions related to merge_switch_to_result() ***/ + +static int checkout(struct merge_options *opt, + struct tree *prev, + struct tree *next) +{ + /* Switch the index/working copy from old to new */ + int ret; + struct tree_desc trees[2]; + struct unpack_trees_options unpack_opts; + + memset(&unpack_opts, 0, sizeof(unpack_opts)); + unpack_opts.head_idx = -1; + unpack_opts.src_index = opt->repo->index; + unpack_opts.dst_index = opt->repo->index; + + setup_unpack_trees_porcelain(&unpack_opts, "merge"); + + /* + * NOTE: if this were just "git checkout" code, we would probably + * read or refresh the cache and check for a conflicted index, but + * builtin/merge.c or sequencer.c really needs to read the index + * and check for conflicted entries before starting merging for a + * good user experience (no sense waiting for merges/rebases before + * erroring out), so there's no reason to duplicate that work here. + */ + + /* 2-way merge to the new branch */ + unpack_opts.update = 1; + unpack_opts.merge = 1; + unpack_opts.quiet = 0; /* FIXME: sequencer might want quiet? */ + unpack_opts.verbose_update = (opt->verbosity > 2); + unpack_opts.fn = twoway_merge; + if (1/* FIXME: opts->overwrite_ignore*/) { + unpack_opts.dir = xcalloc(1, sizeof(*unpack_opts.dir)); + unpack_opts.dir->flags |= DIR_SHOW_IGNORED; + setup_standard_excludes(unpack_opts.dir); + } + parse_tree(prev); + init_tree_desc(&trees[0], prev->buffer, prev->size); + parse_tree(next); + init_tree_desc(&trees[1], next->buffer, next->size); + + ret = unpack_trees(2, trees, &unpack_opts); + clear_unpack_trees_porcelain(&unpack_opts); + dir_clear(unpack_opts.dir); + FREE_AND_NULL(unpack_opts.dir); + return ret; +} + +static int record_conflicted_index_entries(struct merge_options *opt, + struct index_state *index, + struct strmap *paths, + struct strmap *conflicted) +{ + struct hashmap_iter iter; + struct strmap_entry *e; + int errs = 0; + int original_cache_nr; + + if (strmap_empty(conflicted)) + return 0; + + original_cache_nr = index->cache_nr; + + /* Put every entry from paths into plist, then sort */ + strmap_for_each_entry(conflicted, &iter, e) { + const char *path = e->key; + struct conflict_info *ci = e->value; + int pos; + struct cache_entry *ce; + int i; + + VERIFY_CI(ci); + + /* + * The index will already have a stage=0 entry for this path, + * because we created an as-merged-as-possible version of the + * file and checkout() moved the working copy and index over + * to that version. + * + * However, previous iterations through this loop will have + * added unstaged entries to the end of the cache which + * ignore the standard alphabetical ordering of cache + * entries and break invariants needed for index_name_pos() + * to work. However, we know the entry we want is before + * those appended cache entries, so do a temporary swap on + * cache_nr to only look through entries of interest. + */ + SWAP(index->cache_nr, original_cache_nr); + pos = index_name_pos(index, path, strlen(path)); + SWAP(index->cache_nr, original_cache_nr); + if (pos < 0) { + if (ci->filemask != 1) + BUG("Conflicted %s but nothing in basic working tree or index; this shouldn't happen", path); + cache_tree_invalidate_path(index, path); + } else { + ce = index->cache[pos]; + + /* + * Clean paths with CE_SKIP_WORKTREE set will not be + * written to the working tree by the unpack_trees() + * call in checkout(). Our conflicted entries would + * have appeared clean to that code since we ignored + * the higher order stages. Thus, we need override + * the CE_SKIP_WORKTREE bit and manually write those + * files to the working disk here. + * + * TODO: Implement this CE_SKIP_WORKTREE fixup. + */ + + /* + * Mark this cache entry for removal and instead add + * new stage>0 entries corresponding to the + * conflicts. If there are many conflicted entries, we + * want to avoid memmove'ing O(NM) entries by + * inserting the new entries one at a time. So, + * instead, we just add the new cache entries to the + * end (ignoring normal index requirements on sort + * order) and sort the index once we're all done. + */ + ce->ce_flags |= CE_REMOVE; + } + + for (i = MERGE_BASE; i <= MERGE_SIDE2; i++) { + struct version_info *vi; + if (!(ci->filemask & (1ul << i))) + continue; + vi = &ci->stages[i]; + ce = make_cache_entry(index, vi->mode, &vi->oid, + path, i+1, 0); + add_index_entry(index, ce, ADD_CACHE_JUST_APPEND); + } + } + + /* + * Remove the unused cache entries (and invalidate the relevant + * cache-trees), then sort the index entries to get the conflicted + * entries we added to the end into their right locations. + */ + remove_marked_cache_entries(index, 1); + QSORT(index->cache, index->cache_nr, cmp_cache_name_compare); + + return errs; +} + +void merge_switch_to_result(struct merge_options *opt, + struct tree *head, + struct merge_result *result, + int update_worktree_and_index, + int display_update_msgs) +{ + assert(opt->priv == NULL); + if (result->clean >= 0 && update_worktree_and_index) { + struct merge_options_internal *opti = result->priv; + + if (checkout(opt, head, result->tree)) { + /* failure to function */ + result->clean = -1; + return; + } + + if (record_conflicted_index_entries(opt, opt->repo->index, + &opti->paths, + &opti->conflicted)) { + /* failure to function */ + result->clean = -1; + return; + } + } + + if (display_update_msgs) { + struct merge_options_internal *opti = result->priv; + struct hashmap_iter iter; + struct strmap_entry *e; + struct string_list olist = STRING_LIST_INIT_NODUP; + int i; + + /* Hack to pre-allocate olist to the desired size */ + ALLOC_GROW(olist.items, strmap_get_size(&opti->output), + olist.alloc); + + /* Put every entry from output into olist, then sort */ + strmap_for_each_entry(&opti->output, &iter, e) { + string_list_append(&olist, e->key)->util = e->value; + } + string_list_sort(&olist); + + /* Iterate over the items, printing them */ + for (i = 0; i < olist.nr; ++i) { + struct strbuf *sb = olist.items[i].util; + + printf("%s", sb->buf); + } + string_list_clear(&olist, 0); + + /* Also include needed rename limit adjustment now */ + diff_warn_rename_limit("merge.renamelimit", + opti->renames.needed_limit, 0); + } + + merge_finalize(opt, result); +} + +void merge_finalize(struct merge_options *opt, + struct merge_result *result) +{ + struct merge_options_internal *opti = result->priv; + + assert(opt->priv == NULL); + + clear_or_reinit_internal_opts(opti, 0); + FREE_AND_NULL(opti); +} + +/*** Function Grouping: helper functions for merge_incore_*() ***/ + +static inline void set_commit_tree(struct commit *c, struct tree *t) +{ + c->maybe_tree = t; +} + +static struct commit *make_virtual_commit(struct repository *repo, + struct tree *tree, + const char *comment) +{ + struct commit *commit = alloc_commit_node(repo); + + set_merge_remote_desc(commit, comment, (struct object *)commit); + set_commit_tree(commit, tree); + commit->object.parsed = 1; + return commit; +} + +static void merge_start(struct merge_options *opt, struct merge_result *result) +{ + /* Sanity checks on opt */ + assert(opt->repo); + + assert(opt->branch1 && opt->branch2); + + assert(opt->detect_directory_renames >= MERGE_DIRECTORY_RENAMES_NONE && + opt->detect_directory_renames <= MERGE_DIRECTORY_RENAMES_TRUE); + assert(opt->rename_limit >= -1); + assert(opt->rename_score >= 0 && opt->rename_score <= MAX_SCORE); + assert(opt->show_rename_progress >= 0 && opt->show_rename_progress <= 1); + + assert(opt->xdl_opts >= 0); + assert(opt->recursive_variant >= MERGE_VARIANT_NORMAL && + opt->recursive_variant <= MERGE_VARIANT_THEIRS); + + /* + * detect_renames, verbosity, buffer_output, and obuf are ignored + * fields that were used by "recursive" rather than "ort" -- but + * sanity check them anyway. + */ + assert(opt->detect_renames >= -1 && + opt->detect_renames <= DIFF_DETECT_COPY); + assert(opt->verbosity >= 0 && opt->verbosity <= 5); + assert(opt->buffer_output <= 2); + assert(opt->obuf.len == 0); + + assert(opt->priv == NULL); + + /* Default to histogram diff. Actually, just hardcode it...for now. */ + opt->xdl_opts = DIFF_WITH_ALG(opt, HISTOGRAM_DIFF); + + /* Initialization of opt->priv, our internal merge data */ + opt->priv = xcalloc(1, sizeof(*opt->priv)); + + /* + * Although we initialize opt->priv->paths with strdup_strings=0, + * that's just to avoid making yet another copy of an allocated + * string. Putting the entry into paths means we are taking + * ownership, so we will later free it. paths_to_free is similar. + * + * In contrast, conflicted just has a subset of keys from paths, so + * we don't want to free those (it'd be a duplicate free). + */ + strmap_init_with_options(&opt->priv->paths, NULL, 0); + strmap_init_with_options(&opt->priv->conflicted, NULL, 0); + string_list_init(&opt->priv->paths_to_free, 0); + + /* + * keys & strbufs in output will sometimes need to outlive "paths", + * so it will have a copy of relevant keys. It's probably a small + * subset of the overall paths that have special output. + */ + strmap_init(&opt->priv->output); +} + +/*** Function Grouping: merge_incore_*() and their internal variants ***/ + +/* + * Originally from merge_trees_internal(); heavily adapted, though. + */ +static void merge_ort_nonrecursive_internal(struct merge_options *opt, + struct tree *merge_base, + struct tree *side1, + struct tree *side2, + struct merge_result *result) +{ + struct object_id working_tree_oid; + + if (collect_merge_info(opt, merge_base, side1, side2) != 0) { + /* + * TRANSLATORS: The %s arguments are: 1) tree hash of a merge + * base, and 2-3) the trees for the two trees we're merging. + */ + err(opt, _("collecting merge info failed for trees %s, %s, %s"), + oid_to_hex(&merge_base->object.oid), + oid_to_hex(&side1->object.oid), + oid_to_hex(&side2->object.oid)); + result->clean = -1; + return; + } + + result->clean = detect_and_process_renames(opt, merge_base, + side1, side2); + process_entries(opt, &working_tree_oid); + + /* Set return values */ + result->tree = parse_tree_indirect(&working_tree_oid); + /* existence of conflicted entries implies unclean */ + result->clean &= strmap_empty(&opt->priv->conflicted); + if (!opt->priv->call_depth) { + result->priv = opt->priv; + opt->priv = NULL; + } +} + +/* + * Originally from merge_recursive_internal(); somewhat adapted, though. + */ +static void merge_ort_internal(struct merge_options *opt, + struct commit_list *merge_bases, + struct commit *h1, + struct commit *h2, + struct merge_result *result) +{ + struct commit_list *iter; + struct commit *merged_merge_bases; + const char *ancestor_name; + struct strbuf merge_base_abbrev = STRBUF_INIT; + + if (!merge_bases) { + merge_bases = get_merge_bases(h1, h2); + /* See merge-ort.h:merge_incore_recursive() declaration NOTE */ + merge_bases = reverse_commit_list(merge_bases); + } + + merged_merge_bases = pop_commit(&merge_bases); + if (merged_merge_bases == NULL) { + /* if there is no common ancestor, use an empty tree */ + struct tree *tree; + + tree = lookup_tree(opt->repo, opt->repo->hash_algo->empty_tree); + merged_merge_bases = make_virtual_commit(opt->repo, tree, + "ancestor"); + ancestor_name = "empty tree"; + } else if (merge_bases) { + ancestor_name = "merged common ancestors"; + } else { + strbuf_add_unique_abbrev(&merge_base_abbrev, + &merged_merge_bases->object.oid, + DEFAULT_ABBREV); + ancestor_name = merge_base_abbrev.buf; + } + + for (iter = merge_bases; iter; iter = iter->next) { + const char *saved_b1, *saved_b2; + struct commit *prev = merged_merge_bases; + + opt->priv->call_depth++; + /* + * When the merge fails, the result contains files + * with conflict markers. The cleanness flag is + * ignored (unless indicating an error), it was never + * actually used, as result of merge_trees has always + * overwritten it: the committed "conflicts" were + * already resolved. + */ + saved_b1 = opt->branch1; + saved_b2 = opt->branch2; + opt->branch1 = "Temporary merge branch 1"; + opt->branch2 = "Temporary merge branch 2"; + merge_ort_internal(opt, NULL, prev, iter->item, result); + if (result->clean < 0) + return; + opt->branch1 = saved_b1; + opt->branch2 = saved_b2; + opt->priv->call_depth--; + + merged_merge_bases = make_virtual_commit(opt->repo, + result->tree, + "merged tree"); + commit_list_insert(prev, &merged_merge_bases->parents); + commit_list_insert(iter->item, + &merged_merge_bases->parents->next); + + clear_or_reinit_internal_opts(opt->priv, 1); + } + + opt->ancestor = ancestor_name; + merge_ort_nonrecursive_internal(opt, + repo_get_commit_tree(opt->repo, + merged_merge_bases), + repo_get_commit_tree(opt->repo, h1), + repo_get_commit_tree(opt->repo, h2), + result); + strbuf_release(&merge_base_abbrev); + opt->ancestor = NULL; /* avoid accidental re-use of opt->ancestor */ +} + +void merge_incore_nonrecursive(struct merge_options *opt, + struct tree *merge_base, + struct tree *side1, + struct tree *side2, + struct merge_result *result) +{ + assert(opt->ancestor != NULL); + merge_start(opt, result); + merge_ort_nonrecursive_internal(opt, merge_base, side1, side2, result); +} + +void merge_incore_recursive(struct merge_options *opt, + struct commit_list *merge_bases, + struct commit *side1, + struct commit *side2, + struct merge_result *result) +{ + /* We set the ancestor label based on the merge_bases */ + assert(opt->ancestor == NULL); + + merge_start(opt, result); + merge_ort_internal(opt, merge_bases, side1, side2, result); +} |