diff options
Diffstat (limited to 'builtin/difftool.c')
| -rw-r--r-- | builtin/difftool.c | 735 |
1 files changed, 735 insertions, 0 deletions
diff --git a/builtin/difftool.c b/builtin/difftool.c new file mode 100644 index 0000000..1354d0e --- /dev/null +++ b/builtin/difftool.c @@ -0,0 +1,735 @@ +/* + * "git difftool" builtin command + * + * This is a wrapper around the GIT_EXTERNAL_DIFF-compatible + * git-difftool--helper script. + * + * This script exports GIT_EXTERNAL_DIFF and GIT_PAGER for use by git. + * The GIT_DIFF* variables are exported for use by git-difftool--helper. + * + * Any arguments that are unknown to this script are forwarded to 'git diff'. + * + * Copyright (C) 2016 Johannes Schindelin + */ +#include "cache.h" +#include "builtin.h" +#include "run-command.h" +#include "exec_cmd.h" +#include "parse-options.h" +#include "argv-array.h" +#include "strbuf.h" +#include "lockfile.h" +#include "dir.h" + +static char *diff_gui_tool; +static int trust_exit_code; + +static const char *const builtin_difftool_usage[] = { + N_("git difftool [<options>] [<commit> [<commit>]] [--] [<path>...]"), + NULL +}; + +static int difftool_config(const char *var, const char *value, void *cb) +{ + if (!strcmp(var, "diff.guitool")) { + diff_gui_tool = xstrdup(value); + return 0; + } + + if (!strcmp(var, "difftool.trustexitcode")) { + trust_exit_code = git_config_bool(var, value); + return 0; + } + + return git_default_config(var, value, cb); +} + +static int print_tool_help(void) +{ + const char *argv[] = { "mergetool", "--tool-help=diff", NULL }; + return run_command_v_opt(argv, RUN_GIT_CMD); +} + +static int parse_index_info(char *p, int *mode1, int *mode2, + struct object_id *oid1, struct object_id *oid2, + char *status) +{ + if (*p != ':') + return error("expected ':', got '%c'", *p); + *mode1 = (int)strtol(p + 1, &p, 8); + if (*p != ' ') + return error("expected ' ', got '%c'", *p); + *mode2 = (int)strtol(p + 1, &p, 8); + if (*p != ' ') + return error("expected ' ', got '%c'", *p); + if (get_oid_hex(++p, oid1)) + return error("expected object ID, got '%s'", p + 1); + p += GIT_SHA1_HEXSZ; + if (*p != ' ') + return error("expected ' ', got '%c'", *p); + if (get_oid_hex(++p, oid2)) + return error("expected object ID, got '%s'", p + 1); + p += GIT_SHA1_HEXSZ; + if (*p != ' ') + return error("expected ' ', got '%c'", *p); + *status = *++p; + if (!*status) + return error("missing status"); + if (p[1] && !isdigit(p[1])) + return error("unexpected trailer: '%s'", p + 1); + return 0; +} + +/* + * Remove any trailing slash from $workdir + * before starting to avoid double slashes in symlink targets. + */ +static void add_path(struct strbuf *buf, size_t base_len, const char *path) +{ + strbuf_setlen(buf, base_len); + if (buf->len && buf->buf[buf->len - 1] != '/') + strbuf_addch(buf, '/'); + strbuf_addstr(buf, path); +} + +/* + * Determine whether we can simply reuse the file in the worktree. + */ +static int use_wt_file(const char *workdir, const char *name, + struct object_id *oid) +{ + struct strbuf buf = STRBUF_INIT; + struct stat st; + int use = 0; + + strbuf_addstr(&buf, workdir); + add_path(&buf, buf.len, name); + + if (!lstat(buf.buf, &st) && !S_ISLNK(st.st_mode)) { + struct object_id wt_oid; + int fd = open(buf.buf, O_RDONLY); + + if (fd >= 0 && + !index_fd(wt_oid.hash, fd, &st, OBJ_BLOB, name, 0)) { + if (is_null_oid(oid)) { + oidcpy(oid, &wt_oid); + use = 1; + } else if (!oidcmp(oid, &wt_oid)) + use = 1; + } + } + + strbuf_release(&buf); + + return use; +} + +struct working_tree_entry { + struct hashmap_entry entry; + char path[FLEX_ARRAY]; +}; + +static int working_tree_entry_cmp(struct working_tree_entry *a, + struct working_tree_entry *b, void *keydata) +{ + return strcmp(a->path, b->path); +} + +/* + * The `left` and `right` entries hold paths for the symlinks hashmap, + * and a SHA-1 surrounded by brief text for submodules. + */ +struct pair_entry { + struct hashmap_entry entry; + char left[PATH_MAX], right[PATH_MAX]; + const char path[FLEX_ARRAY]; +}; + +static int pair_cmp(struct pair_entry *a, struct pair_entry *b, void *keydata) +{ + return strcmp(a->path, b->path); +} + +static void add_left_or_right(struct hashmap *map, const char *path, + const char *content, int is_right) +{ + struct pair_entry *e, *existing; + + FLEX_ALLOC_STR(e, path, path); + hashmap_entry_init(e, strhash(path)); + existing = hashmap_get(map, e, NULL); + if (existing) { + free(e); + e = existing; + } else { + e->left[0] = e->right[0] = '\0'; + hashmap_add(map, e); + } + strlcpy(is_right ? e->right : e->left, content, PATH_MAX); +} + +struct path_entry { + struct hashmap_entry entry; + char path[FLEX_ARRAY]; +}; + +static int path_entry_cmp(struct path_entry *a, struct path_entry *b, void *key) +{ + return strcmp(a->path, key ? key : b->path); +} + +static void changed_files(struct hashmap *result, const char *index_path, + const char *workdir) +{ + struct child_process update_index = CHILD_PROCESS_INIT; + struct child_process diff_files = CHILD_PROCESS_INIT; + struct strbuf index_env = STRBUF_INIT, buf = STRBUF_INIT; + const char *git_dir = absolute_path(get_git_dir()), *env[] = { + NULL, NULL + }; + FILE *fp; + + strbuf_addf(&index_env, "GIT_INDEX_FILE=%s", index_path); + env[0] = index_env.buf; + + argv_array_pushl(&update_index.args, + "--git-dir", git_dir, "--work-tree", workdir, + "update-index", "--really-refresh", "-q", + "--unmerged", NULL); + update_index.no_stdin = 1; + update_index.no_stdout = 1; + update_index.no_stderr = 1; + update_index.git_cmd = 1; + update_index.use_shell = 0; + update_index.clean_on_exit = 1; + update_index.dir = workdir; + update_index.env = env; + /* Ignore any errors of update-index */ + run_command(&update_index); + + argv_array_pushl(&diff_files.args, + "--git-dir", git_dir, "--work-tree", workdir, + "diff-files", "--name-only", "-z", NULL); + diff_files.no_stdin = 1; + diff_files.git_cmd = 1; + diff_files.use_shell = 0; + diff_files.clean_on_exit = 1; + diff_files.out = -1; + diff_files.dir = workdir; + diff_files.env = env; + if (start_command(&diff_files)) + die("could not obtain raw diff"); + fp = xfdopen(diff_files.out, "r"); + while (!strbuf_getline_nul(&buf, fp)) { + struct path_entry *entry; + FLEX_ALLOC_STR(entry, path, buf.buf); + hashmap_entry_init(entry, strhash(buf.buf)); + hashmap_add(result, entry); + } + if (finish_command(&diff_files)) + die("diff-files did not exit properly"); + strbuf_release(&index_env); + strbuf_release(&buf); +} + +static NORETURN void exit_cleanup(const char *tmpdir, int exit_code) +{ + struct strbuf buf = STRBUF_INIT; + strbuf_addstr(&buf, tmpdir); + remove_dir_recursively(&buf, 0); + if (exit_code) + warning(_("failed: %d"), exit_code); + exit(exit_code); +} + +static int ensure_leading_directories(char *path) +{ + switch (safe_create_leading_directories(path)) { + case SCLD_OK: + case SCLD_EXISTS: + return 0; + default: + return error(_("could not create leading directories " + "of '%s'"), path); + } +} + +/* + * Unconditional writing of a plain regular file is what + * "git difftool --dir-diff" wants to do for symlinks. We are preparing two + * temporary directories to be fed to a Git-unaware tool that knows how to + * show a diff of two directories (e.g. "diff -r A B"). + * + * Because the tool is Git-unaware, if a symbolic link appears in either of + * these temporary directories, it will try to dereference and show the + * difference of the target of the symbolic link, which is not what we want, + * as the goal of the dir-diff mode is to produce an output that is logically + * equivalent to what "git diff" produces. + * + * Most importantly, we want to get textual comparison of the result of the + * readlink(2). get_symlink() provides that---it returns the contents of + * the symlink that gets written to a regular file to force the external tool + * to compare the readlink(2) result as text, even on a filesystem that is + * capable of doing a symbolic link. + */ +static char *get_symlink(const struct object_id *oid, const char *path) +{ + char *data; + if (is_null_oid(oid)) { + /* The symlink is unknown to Git so read from the filesystem */ + struct strbuf link = STRBUF_INIT; + if (has_symlinks) { + if (strbuf_readlink(&link, path, strlen(path))) + die(_("could not read symlink %s"), path); + } else if (strbuf_read_file(&link, path, 128)) + die(_("could not read symlink file %s"), path); + + data = strbuf_detach(&link, NULL); + } else { + enum object_type type; + unsigned long size; + data = read_sha1_file(oid->hash, &type, &size); + if (!data) + die(_("could not read object %s for symlink %s"), + oid_to_hex(oid), path); + } + + return data; +} + +static int checkout_path(unsigned mode, struct object_id *oid, + const char *path, const struct checkout *state) +{ + struct cache_entry *ce; + int ret; + + ce = make_cache_entry(mode, oid->hash, path, 0, 0); + ret = checkout_entry(ce, state, NULL); + + free(ce); + return ret; +} + +static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix, + int argc, const char **argv) +{ + char tmpdir[PATH_MAX]; + struct strbuf info = STRBUF_INIT, lpath = STRBUF_INIT; + struct strbuf rpath = STRBUF_INIT, buf = STRBUF_INIT; + struct strbuf ldir = STRBUF_INIT, rdir = STRBUF_INIT; + struct strbuf wtdir = STRBUF_INIT; + char *lbase_dir, *rbase_dir; + size_t ldir_len, rdir_len, wtdir_len; + const char *workdir, *tmp; + int ret = 0, i; + FILE *fp; + struct hashmap working_tree_dups, submodules, symlinks2; + struct hashmap_iter iter; + struct pair_entry *entry; + struct index_state wtindex; + struct checkout lstate, rstate; + int rc, flags = RUN_GIT_CMD, err = 0; + struct child_process child = CHILD_PROCESS_INIT; + const char *helper_argv[] = { "difftool--helper", NULL, NULL, NULL }; + struct hashmap wt_modified, tmp_modified; + int indices_loaded = 0; + + workdir = get_git_work_tree(); + + /* Setup temp directories */ + tmp = getenv("TMPDIR"); + xsnprintf(tmpdir, sizeof(tmpdir), "%s/git-difftool.XXXXXX", tmp ? tmp : "/tmp"); + if (!mkdtemp(tmpdir)) + return error("could not create '%s'", tmpdir); + strbuf_addf(&ldir, "%s/left/", tmpdir); + strbuf_addf(&rdir, "%s/right/", tmpdir); + strbuf_addstr(&wtdir, workdir); + if (!wtdir.len || !is_dir_sep(wtdir.buf[wtdir.len - 1])) + strbuf_addch(&wtdir, '/'); + mkdir(ldir.buf, 0700); + mkdir(rdir.buf, 0700); + + memset(&wtindex, 0, sizeof(wtindex)); + + memset(&lstate, 0, sizeof(lstate)); + lstate.base_dir = lbase_dir = xstrdup(ldir.buf); + lstate.base_dir_len = ldir.len; + lstate.force = 1; + memset(&rstate, 0, sizeof(rstate)); + rstate.base_dir = rbase_dir = xstrdup(rdir.buf); + rstate.base_dir_len = rdir.len; + rstate.force = 1; + + ldir_len = ldir.len; + rdir_len = rdir.len; + wtdir_len = wtdir.len; + + hashmap_init(&working_tree_dups, + (hashmap_cmp_fn)working_tree_entry_cmp, 0); + hashmap_init(&submodules, (hashmap_cmp_fn)pair_cmp, 0); + hashmap_init(&symlinks2, (hashmap_cmp_fn)pair_cmp, 0); + + child.no_stdin = 1; + child.git_cmd = 1; + child.use_shell = 0; + child.clean_on_exit = 1; + child.dir = prefix; + child.out = -1; + argv_array_pushl(&child.args, "diff", "--raw", "--no-abbrev", "-z", + NULL); + for (i = 0; i < argc; i++) + argv_array_push(&child.args, argv[i]); + if (start_command(&child)) + die("could not obtain raw diff"); + fp = xfdopen(child.out, "r"); + + /* Build index info for left and right sides of the diff */ + i = 0; + while (!strbuf_getline_nul(&info, fp)) { + int lmode, rmode; + struct object_id loid, roid; + char status; + const char *src_path, *dst_path; + + if (starts_with(info.buf, "::")) + die(N_("combined diff formats('-c' and '--cc') are " + "not supported in\n" + "directory diff mode('-d' and '--dir-diff').")); + + if (parse_index_info(info.buf, &lmode, &rmode, &loid, &roid, + &status)) + break; + if (strbuf_getline_nul(&lpath, fp)) + break; + src_path = lpath.buf; + + i++; + if (status != 'C' && status != 'R') { + dst_path = src_path; + } else { + if (strbuf_getline_nul(&rpath, fp)) + break; + dst_path = rpath.buf; + } + + if (S_ISGITLINK(lmode) || S_ISGITLINK(rmode)) { + strbuf_reset(&buf); + strbuf_addf(&buf, "Subproject commit %s", + oid_to_hex(&loid)); + add_left_or_right(&submodules, src_path, buf.buf, 0); + strbuf_reset(&buf); + strbuf_addf(&buf, "Subproject commit %s", + oid_to_hex(&roid)); + if (!oidcmp(&loid, &roid)) + strbuf_addstr(&buf, "-dirty"); + add_left_or_right(&submodules, dst_path, buf.buf, 1); + continue; + } + + if (S_ISLNK(lmode)) { + char *content = get_symlink(&loid, src_path); + add_left_or_right(&symlinks2, src_path, content, 0); + free(content); + } + + if (S_ISLNK(rmode)) { + char *content = get_symlink(&roid, dst_path); + add_left_or_right(&symlinks2, dst_path, content, 1); + free(content); + } + + if (lmode && status != 'C') { + if (checkout_path(lmode, &loid, src_path, &lstate)) + return error("could not write '%s'", src_path); + } + + if (rmode && !S_ISLNK(rmode)) { + struct working_tree_entry *entry; + + /* Avoid duplicate working_tree entries */ + FLEX_ALLOC_STR(entry, path, dst_path); + hashmap_entry_init(entry, strhash(dst_path)); + if (hashmap_get(&working_tree_dups, entry, NULL)) { + free(entry); + continue; + } + hashmap_add(&working_tree_dups, entry); + + if (!use_wt_file(workdir, dst_path, &roid)) { + if (checkout_path(rmode, &roid, dst_path, &rstate)) + return error("could not write '%s'", + dst_path); + } else if (!is_null_oid(&roid)) { + /* + * Changes in the working tree need special + * treatment since they are not part of the + * index. + */ + struct cache_entry *ce2 = + make_cache_entry(rmode, roid.hash, + dst_path, 0, 0); + + add_index_entry(&wtindex, ce2, + ADD_CACHE_JUST_APPEND); + + add_path(&rdir, rdir_len, dst_path); + if (ensure_leading_directories(rdir.buf)) + return error("could not create " + "directory for '%s'", + dst_path); + add_path(&wtdir, wtdir_len, dst_path); + if (symlinks) { + if (symlink(wtdir.buf, rdir.buf)) { + ret = error_errno("could not symlink '%s' to '%s'", wtdir.buf, rdir.buf); + goto finish; + } + } else { + struct stat st; + if (stat(wtdir.buf, &st)) + st.st_mode = 0644; + if (copy_file(rdir.buf, wtdir.buf, + st.st_mode)) { + ret = error("could not copy '%s' to '%s'", wtdir.buf, rdir.buf); + goto finish; + } + } + } + } + } + + if (finish_command(&child)) { + ret = error("error occurred running diff --raw"); + goto finish; + } + + if (!i) + return 0; + + /* + * Changes to submodules require special treatment.This loop writes a + * temporary file to both the left and right directories to show the + * change in the recorded SHA1 for the submodule. + */ + hashmap_iter_init(&submodules, &iter); + while ((entry = hashmap_iter_next(&iter))) { + if (*entry->left) { + add_path(&ldir, ldir_len, entry->path); + ensure_leading_directories(ldir.buf); + write_file(ldir.buf, "%s", entry->left); + } + if (*entry->right) { + add_path(&rdir, rdir_len, entry->path); + ensure_leading_directories(rdir.buf); + write_file(rdir.buf, "%s", entry->right); + } + } + + /* + * Symbolic links require special treatment.The standard "git diff" + * shows only the link itself, not the contents of the link target. + * This loop replicates that behavior. + */ + hashmap_iter_init(&symlinks2, &iter); + while ((entry = hashmap_iter_next(&iter))) { + if (*entry->left) { + add_path(&ldir, ldir_len, entry->path); + ensure_leading_directories(ldir.buf); + write_file(ldir.buf, "%s", entry->left); + } + if (*entry->right) { + add_path(&rdir, rdir_len, entry->path); + ensure_leading_directories(rdir.buf); + write_file(rdir.buf, "%s", entry->right); + } + } + + strbuf_release(&buf); + + strbuf_setlen(&ldir, ldir_len); + helper_argv[1] = ldir.buf; + strbuf_setlen(&rdir, rdir_len); + helper_argv[2] = rdir.buf; + + if (extcmd) { + helper_argv[0] = extcmd; + flags = 0; + } else + setenv("GIT_DIFFTOOL_DIRDIFF", "true", 1); + rc = run_command_v_opt(helper_argv, flags); + + /* + * If the diff includes working copy files and those + * files were modified during the diff, then the changes + * should be copied back to the working tree. + * Do not copy back files when symlinks are used and the + * external tool did not replace the original link with a file. + * + * These hashes are loaded lazily since they aren't needed + * in the common case of --symlinks and the difftool updating + * files through the symlink. + */ + hashmap_init(&wt_modified, (hashmap_cmp_fn)path_entry_cmp, + wtindex.cache_nr); + hashmap_init(&tmp_modified, (hashmap_cmp_fn)path_entry_cmp, + wtindex.cache_nr); + + for (i = 0; i < wtindex.cache_nr; i++) { + struct hashmap_entry dummy; + const char *name = wtindex.cache[i]->name; + struct stat st; + + add_path(&rdir, rdir_len, name); + if (lstat(rdir.buf, &st)) + continue; + + if ((symlinks && S_ISLNK(st.st_mode)) || !S_ISREG(st.st_mode)) + continue; + + if (!indices_loaded) { + static struct lock_file lock; + strbuf_reset(&buf); + strbuf_addf(&buf, "%s/wtindex", tmpdir); + if (hold_lock_file_for_update(&lock, buf.buf, 0) < 0 || + write_locked_index(&wtindex, &lock, COMMIT_LOCK)) { + ret = error("could not write %s", buf.buf); + rollback_lock_file(&lock); + goto finish; + } + changed_files(&wt_modified, buf.buf, workdir); + strbuf_setlen(&rdir, rdir_len); + changed_files(&tmp_modified, buf.buf, rdir.buf); + add_path(&rdir, rdir_len, name); + indices_loaded = 1; + } + + hashmap_entry_init(&dummy, strhash(name)); + if (hashmap_get(&tmp_modified, &dummy, name)) { + add_path(&wtdir, wtdir_len, name); + if (hashmap_get(&wt_modified, &dummy, name)) { + warning(_("both files modified: '%s' and '%s'."), + wtdir.buf, rdir.buf); + warning(_("working tree file has been left.")); + warning("%s", ""); + err = 1; + } else if (unlink(wtdir.buf) || + copy_file(wtdir.buf, rdir.buf, st.st_mode)) + warning_errno(_("could not copy '%s' to '%s'"), + rdir.buf, wtdir.buf); + } + } + + if (err) { + warning(_("temporary files exist in '%s'."), tmpdir); + warning(_("you may want to cleanup or recover these.")); + exit(1); + } else + exit_cleanup(tmpdir, rc); + +finish: + free(lbase_dir); + free(rbase_dir); + strbuf_release(&ldir); + strbuf_release(&rdir); + strbuf_release(&wtdir); + strbuf_release(&buf); + + return ret; +} + +static int run_file_diff(int prompt, const char *prefix, + int argc, const char **argv) +{ + struct argv_array args = ARGV_ARRAY_INIT; + const char *env[] = { + "GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL, + NULL + }; + int ret = 0, i; + + if (prompt > 0) + env[2] = "GIT_DIFFTOOL_PROMPT=true"; + else if (!prompt) + env[2] = "GIT_DIFFTOOL_NO_PROMPT=true"; + + + argv_array_push(&args, "diff"); + for (i = 0; i < argc; i++) + argv_array_push(&args, argv[i]); + ret = run_command_v_opt_cd_env(args.argv, RUN_GIT_CMD, prefix, env); + exit(ret); +} + +int cmd_difftool(int argc, const char **argv, const char *prefix) +{ + int use_gui_tool = 0, dir_diff = 0, prompt = -1, symlinks = 0, + tool_help = 0; + static char *difftool_cmd = NULL, *extcmd = NULL; + struct option builtin_difftool_options[] = { + OPT_BOOL('g', "gui", &use_gui_tool, + N_("use `diff.guitool` instead of `diff.tool`")), + OPT_BOOL('d', "dir-diff", &dir_diff, + N_("perform a full-directory diff")), + { OPTION_SET_INT, 'y', "no-prompt", &prompt, NULL, + N_("do not prompt before launching a diff tool"), + PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0}, + { OPTION_SET_INT, 0, "prompt", &prompt, NULL, NULL, + PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_HIDDEN, + NULL, 1 }, + OPT_BOOL(0, "symlinks", &symlinks, + N_("use symlinks in dir-diff mode")), + OPT_STRING('t', "tool", &difftool_cmd, N_("<tool>"), + N_("use the specified diff tool")), + OPT_BOOL(0, "tool-help", &tool_help, + N_("print a list of diff tools that may be used with " + "`--tool`")), + OPT_BOOL(0, "trust-exit-code", &trust_exit_code, + N_("make 'git-difftool' exit when an invoked diff " + "tool returns a non - zero exit code")), + OPT_STRING('x', "extcmd", &extcmd, N_("<command>"), + N_("specify a custom command for viewing diffs")), + OPT_END() + }; + + git_config(difftool_config, NULL); + symlinks = has_symlinks; + + argc = parse_options(argc, argv, prefix, builtin_difftool_options, + builtin_difftool_usage, PARSE_OPT_KEEP_UNKNOWN | + PARSE_OPT_KEEP_DASHDASH); + + if (tool_help) + return print_tool_help(); + + /* NEEDSWORK: once we no longer spawn anything, remove this */ + setenv(GIT_DIR_ENVIRONMENT, absolute_path(get_git_dir()), 1); + setenv(GIT_WORK_TREE_ENVIRONMENT, absolute_path(get_git_work_tree()), 1); + + if (use_gui_tool && diff_gui_tool && *diff_gui_tool) + setenv("GIT_DIFF_TOOL", diff_gui_tool, 1); + else if (difftool_cmd) { + if (*difftool_cmd) + setenv("GIT_DIFF_TOOL", difftool_cmd, 1); + else + die(_("no <tool> given for --tool=<tool>")); + } + + if (extcmd) { + if (*extcmd) + setenv("GIT_DIFFTOOL_EXTCMD", extcmd, 1); + else + die(_("no <cmd> given for --extcmd=<cmd>")); + } + + setenv("GIT_DIFFTOOL_TRUST_EXIT_CODE", + trust_exit_code ? "true" : "false", 1); + + /* + * In directory diff mode, 'git-difftool--helper' is called once + * to compare the a / b directories. In file diff mode, 'git diff' + * will invoke a separate instance of 'git-difftool--helper' for + * each file that changed. + */ + if (dir_diff) + return run_dir_diff(extcmd, symlinks, prefix, argc, argv); + return run_file_diff(prompt, prefix, argc, argv); +} |