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-rw-r--r--builtin-checkout.c573
1 files changed, 573 insertions, 0 deletions
diff --git a/builtin-checkout.c b/builtin-checkout.c
new file mode 100644
index 0000000..d5f0930
--- /dev/null
+++ b/builtin-checkout.c
@@ -0,0 +1,573 @@
+#include "cache.h"
+#include "builtin.h"
+#include "parse-options.h"
+#include "refs.h"
+#include "commit.h"
+#include "tree.h"
+#include "tree-walk.h"
+#include "unpack-trees.h"
+#include "dir.h"
+#include "run-command.h"
+#include "merge-recursive.h"
+#include "branch.h"
+#include "diff.h"
+#include "revision.h"
+#include "remote.h"
+
+static const char * const checkout_usage[] = {
+ "git checkout [options] <branch>",
+ "git checkout [options] [<branch>] -- <file>...",
+ NULL,
+};
+
+static int post_checkout_hook(struct commit *old, struct commit *new,
+ int changed)
+{
+ struct child_process proc;
+ const char *name = git_path("hooks/post-checkout");
+ const char *argv[5];
+
+ if (access(name, X_OK) < 0)
+ return 0;
+
+ memset(&proc, 0, sizeof(proc));
+ argv[0] = name;
+ argv[1] = xstrdup(sha1_to_hex(old->object.sha1));
+ argv[2] = xstrdup(sha1_to_hex(new->object.sha1));
+ argv[3] = changed ? "1" : "0";
+ argv[4] = NULL;
+ proc.argv = argv;
+ proc.no_stdin = 1;
+ proc.stdout_to_stderr = 1;
+ return run_command(&proc);
+}
+
+static int update_some(const unsigned char *sha1, const char *base, int baselen,
+ const char *pathname, unsigned mode, int stage)
+{
+ int len;
+ struct cache_entry *ce;
+
+ if (S_ISGITLINK(mode))
+ return 0;
+
+ if (S_ISDIR(mode))
+ return READ_TREE_RECURSIVE;
+
+ len = baselen + strlen(pathname);
+ ce = xcalloc(1, cache_entry_size(len));
+ hashcpy(ce->sha1, sha1);
+ memcpy(ce->name, base, baselen);
+ memcpy(ce->name + baselen, pathname, len - baselen);
+ ce->ce_flags = create_ce_flags(len, 0);
+ ce->ce_mode = create_ce_mode(mode);
+ add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
+ return 0;
+}
+
+static int read_tree_some(struct tree *tree, const char **pathspec)
+{
+ int newfd;
+ struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
+ newfd = hold_locked_index(lock_file, 1);
+ read_cache();
+
+ read_tree_recursive(tree, "", 0, 0, pathspec, update_some);
+
+ if (write_cache(newfd, active_cache, active_nr) ||
+ commit_locked_index(lock_file))
+ die("unable to write new index file");
+
+ /* update the index with the given tree's info
+ * for all args, expanding wildcards, and exit
+ * with any non-zero return code.
+ */
+ return 0;
+}
+
+static int checkout_paths(const char **pathspec)
+{
+ int pos;
+ struct checkout state;
+ static char *ps_matched;
+ unsigned char rev[20];
+ int flag;
+ struct commit *head;
+
+ for (pos = 0; pathspec[pos]; pos++)
+ ;
+ ps_matched = xcalloc(1, pos);
+
+ for (pos = 0; pos < active_nr; pos++) {
+ struct cache_entry *ce = active_cache[pos];
+ pathspec_match(pathspec, ps_matched, ce->name, 0);
+ }
+
+ if (report_path_error(ps_matched, pathspec, 0))
+ return 1;
+
+ memset(&state, 0, sizeof(state));
+ state.force = 1;
+ state.refresh_cache = 1;
+ for (pos = 0; pos < active_nr; pos++) {
+ struct cache_entry *ce = active_cache[pos];
+ if (pathspec_match(pathspec, NULL, ce->name, 0)) {
+ checkout_entry(ce, &state, NULL);
+ }
+ }
+
+ resolve_ref("HEAD", rev, 0, &flag);
+ head = lookup_commit_reference_gently(rev, 1);
+
+ return post_checkout_hook(head, head, 0);
+}
+
+static void show_local_changes(struct object *head)
+{
+ struct rev_info rev;
+ /* I think we want full paths, even if we're in a subdirectory. */
+ init_revisions(&rev, NULL);
+ rev.abbrev = 0;
+ rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
+ add_pending_object(&rev, head, NULL);
+ run_diff_index(&rev, 0);
+}
+
+static void describe_detached_head(char *msg, struct commit *commit)
+{
+ struct strbuf sb;
+ strbuf_init(&sb, 0);
+ parse_commit(commit);
+ pretty_print_commit(CMIT_FMT_ONELINE, commit, &sb, 0, "", "", 0, 0);
+ fprintf(stderr, "%s %s... %s\n", msg,
+ find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV), sb.buf);
+ strbuf_release(&sb);
+}
+
+static int reset_to_new(struct tree *tree, int quiet)
+{
+ struct unpack_trees_options opts;
+ struct tree_desc tree_desc;
+ memset(&opts, 0, sizeof(opts));
+ opts.head_idx = -1;
+ opts.update = 1;
+ opts.reset = 1;
+ opts.merge = 1;
+ opts.fn = oneway_merge;
+ opts.verbose_update = !quiet;
+ parse_tree(tree);
+ init_tree_desc(&tree_desc, tree->buffer, tree->size);
+ if (unpack_trees(1, &tree_desc, &opts))
+ return 128;
+ return 0;
+}
+
+static void reset_clean_to_new(struct tree *tree, int quiet)
+{
+ struct unpack_trees_options opts;
+ struct tree_desc tree_desc;
+ memset(&opts, 0, sizeof(opts));
+ opts.head_idx = -1;
+ opts.skip_unmerged = 1;
+ opts.reset = 1;
+ opts.merge = 1;
+ opts.fn = oneway_merge;
+ opts.verbose_update = !quiet;
+ parse_tree(tree);
+ init_tree_desc(&tree_desc, tree->buffer, tree->size);
+ if (unpack_trees(1, &tree_desc, &opts))
+ exit(128);
+}
+
+struct checkout_opts {
+ int quiet;
+ int merge;
+ int force;
+
+ char *new_branch;
+ int new_branch_log;
+ int track;
+};
+
+struct branch_info {
+ const char *name; /* The short name used */
+ const char *path; /* The full name of a real branch */
+ struct commit *commit; /* The named commit */
+};
+
+static void setup_branch_path(struct branch_info *branch)
+{
+ struct strbuf buf;
+ strbuf_init(&buf, 0);
+ strbuf_addstr(&buf, "refs/heads/");
+ strbuf_addstr(&buf, branch->name);
+ branch->path = strbuf_detach(&buf, NULL);
+}
+
+static int merge_working_tree(struct checkout_opts *opts,
+ struct branch_info *old, struct branch_info *new)
+{
+ int ret;
+ struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
+ int newfd = hold_locked_index(lock_file, 1);
+ read_cache();
+
+ if (opts->force) {
+ ret = reset_to_new(new->commit->tree, opts->quiet);
+ if (ret)
+ return ret;
+ } else {
+ struct tree_desc trees[2];
+ struct tree *tree;
+ struct unpack_trees_options topts;
+ memset(&topts, 0, sizeof(topts));
+ topts.head_idx = -1;
+
+ refresh_cache(REFRESH_QUIET);
+
+ if (unmerged_cache()) {
+ error("you need to resolve your current index first");
+ return 1;
+ }
+
+ /* 2-way merge to the new branch */
+ topts.update = 1;
+ topts.merge = 1;
+ topts.gently = opts->merge;
+ topts.verbose_update = !opts->quiet;
+ topts.fn = twoway_merge;
+ topts.dir = xcalloc(1, sizeof(*topts.dir));
+ topts.dir->show_ignored = 1;
+ topts.dir->exclude_per_dir = ".gitignore";
+ tree = parse_tree_indirect(old->commit->object.sha1);
+ init_tree_desc(&trees[0], tree->buffer, tree->size);
+ tree = parse_tree_indirect(new->commit->object.sha1);
+ init_tree_desc(&trees[1], tree->buffer, tree->size);
+
+ if (unpack_trees(2, trees, &topts)) {
+ /*
+ * Unpack couldn't do a trivial merge; either
+ * give up or do a real merge, depending on
+ * whether the merge flag was used.
+ */
+ struct tree *result;
+ struct tree *work;
+ if (!opts->merge)
+ return 1;
+ parse_commit(old->commit);
+
+ /* Do more real merge */
+
+ /*
+ * We update the index fully, then write the
+ * tree from the index, then merge the new
+ * branch with the current tree, with the old
+ * branch as the base. Then we reset the index
+ * (but not the working tree) to the new
+ * branch, leaving the working tree as the
+ * merged version, but skipping unmerged
+ * entries in the index.
+ */
+
+ add_files_to_cache(0, NULL, NULL);
+ work = write_tree_from_memory();
+
+ ret = reset_to_new(new->commit->tree, opts->quiet);
+ if (ret)
+ return ret;
+ merge_trees(new->commit->tree, work, old->commit->tree,
+ new->name, "local", &result);
+ reset_clean_to_new(new->commit->tree, opts->quiet);
+ }
+ }
+
+ if (write_cache(newfd, active_cache, active_nr) ||
+ commit_locked_index(lock_file))
+ die("unable to write new index file");
+
+ if (!opts->force)
+ show_local_changes(&new->commit->object);
+
+ return 0;
+}
+
+static void report_tracking(struct branch_info *new, struct checkout_opts *opts)
+{
+ /*
+ * We have switched to a new branch; is it building on
+ * top of another branch, and if so does that other branch
+ * have changes we do not have yet?
+ */
+ char *base;
+ unsigned char sha1[20];
+ struct commit *ours, *theirs;
+ char symmetric[84];
+ struct rev_info revs;
+ const char *rev_argv[10];
+ int rev_argc;
+ int num_ours, num_theirs;
+ const char *remote_msg;
+ struct branch *branch = branch_get(new->name);
+
+ /*
+ * Nothing to report unless we are marked to build on top of
+ * somebody else.
+ */
+ if (!branch || !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
+ return;
+
+ /*
+ * If what we used to build on no longer exists, there is
+ * nothing to report.
+ */
+ base = branch->merge[0]->dst;
+ if (!resolve_ref(base, sha1, 1, NULL))
+ return;
+
+ theirs = lookup_commit(sha1);
+ ours = new->commit;
+ if (!hashcmp(sha1, ours->object.sha1))
+ return; /* we are the same */
+
+ /* Run "rev-list --left-right ours...theirs" internally... */
+ rev_argc = 0;
+ rev_argv[rev_argc++] = NULL;
+ rev_argv[rev_argc++] = "--left-right";
+ rev_argv[rev_argc++] = symmetric;
+ rev_argv[rev_argc++] = "--";
+ rev_argv[rev_argc] = NULL;
+
+ strcpy(symmetric, sha1_to_hex(ours->object.sha1));
+ strcpy(symmetric + 40, "...");
+ strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
+
+ init_revisions(&revs, NULL);
+ setup_revisions(rev_argc, rev_argv, &revs, NULL);
+ prepare_revision_walk(&revs);
+
+ /* ... and count the commits on each side. */
+ num_ours = 0;
+ num_theirs = 0;
+ while (1) {
+ struct commit *c = get_revision(&revs);
+ if (!c)
+ break;
+ if (c->object.flags & SYMMETRIC_LEFT)
+ num_ours++;
+ else
+ num_theirs++;
+ }
+
+ if (!prefixcmp(base, "refs/remotes/")) {
+ remote_msg = " remote";
+ base += strlen("refs/remotes/");
+ } else {
+ remote_msg = "";
+ }
+
+ if (!num_theirs)
+ printf("Your branch is ahead of the tracked%s branch '%s' "
+ "by %d commit%s.\n",
+ remote_msg, base,
+ num_ours, (num_ours == 1) ? "" : "s");
+ else if (!num_ours)
+ printf("Your branch is behind the tracked%s branch '%s' "
+ "by %d commit%s,\n"
+ "and can be fast-forwarded.\n",
+ remote_msg, base,
+ num_theirs, (num_theirs == 1) ? "" : "s");
+ else
+ printf("Your branch and the tracked%s branch '%s' "
+ "have diverged,\nand respectively "
+ "have %d and %d different commit(s) each.\n",
+ remote_msg, base,
+ num_ours, num_theirs);
+}
+
+static void update_refs_for_switch(struct checkout_opts *opts,
+ struct branch_info *old,
+ struct branch_info *new)
+{
+ struct strbuf msg;
+ const char *old_desc;
+ if (opts->new_branch) {
+ create_branch(old->name, opts->new_branch, new->name, 0,
+ opts->new_branch_log, opts->track);
+ new->name = opts->new_branch;
+ setup_branch_path(new);
+ }
+
+ strbuf_init(&msg, 0);
+ old_desc = old->name;
+ if (!old_desc)
+ old_desc = sha1_to_hex(old->commit->object.sha1);
+ strbuf_addf(&msg, "checkout: moving from %s to %s",
+ old_desc, new->name);
+
+ if (new->path) {
+ create_symref("HEAD", new->path, msg.buf);
+ if (!opts->quiet) {
+ if (old->path && !strcmp(new->path, old->path))
+ fprintf(stderr, "Already on \"%s\"\n",
+ new->name);
+ else
+ fprintf(stderr, "Switched to%s branch \"%s\"\n",
+ opts->new_branch ? " a new" : "",
+ new->name);
+ }
+ } else if (strcmp(new->name, "HEAD")) {
+ update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
+ REF_NODEREF, DIE_ON_ERR);
+ if (!opts->quiet) {
+ if (old->path)
+ fprintf(stderr, "Note: moving to \"%s\" which isn't a local branch\nIf you want to create a new branch from this checkout, you may do so\n(now or later) by using -b with the checkout command again. Example:\n git checkout -b <new_branch_name>\n", new->name);
+ describe_detached_head("HEAD is now at", new->commit);
+ }
+ }
+ remove_branch_state();
+ strbuf_release(&msg);
+ if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
+ report_tracking(new, opts);
+}
+
+static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
+{
+ int ret = 0;
+ struct branch_info old;
+ unsigned char rev[20];
+ int flag;
+ memset(&old, 0, sizeof(old));
+ old.path = resolve_ref("HEAD", rev, 0, &flag);
+ old.commit = lookup_commit_reference_gently(rev, 1);
+ if (!(flag & REF_ISSYMREF))
+ old.path = NULL;
+
+ if (old.path && !prefixcmp(old.path, "refs/heads/"))
+ old.name = old.path + strlen("refs/heads/");
+
+ if (!new->name) {
+ new->name = "HEAD";
+ new->commit = old.commit;
+ if (!new->commit)
+ die("You are on a branch yet to be born");
+ parse_commit(new->commit);
+ }
+
+ /*
+ * If the new thing isn't a branch and isn't HEAD and we're
+ * not starting a new branch, and we want messages, and we
+ * weren't on a branch, and we're moving to a new commit,
+ * describe the old commit.
+ */
+ if (!new->path && strcmp(new->name, "HEAD") && !opts->new_branch &&
+ !opts->quiet && !old.path && new->commit != old.commit)
+ describe_detached_head("Previous HEAD position was", old.commit);
+
+ if (!old.commit) {
+ if (!opts->quiet) {
+ fprintf(stderr, "warning: You appear to be on a branch yet to be born.\n");
+ fprintf(stderr, "warning: Forcing checkout of %s.\n", new->name);
+ }
+ opts->force = 1;
+ }
+
+ ret = merge_working_tree(opts, &old, new);
+ if (ret)
+ return ret;
+
+ update_refs_for_switch(opts, &old, new);
+
+ return post_checkout_hook(old.commit, new->commit, 1);
+}
+
+static int branch_track = 0;
+
+static int git_checkout_config(const char *var, const char *value)
+{
+ if (!strcmp(var, "branch.autosetupmerge"))
+ branch_track = git_config_bool(var, value);
+
+ return git_default_config(var, value);
+}
+
+int cmd_checkout(int argc, const char **argv, const char *prefix)
+{
+ struct checkout_opts opts;
+ unsigned char rev[20];
+ const char *arg;
+ struct branch_info new;
+ struct tree *source_tree = NULL;
+ struct option options[] = {
+ OPT__QUIET(&opts.quiet),
+ OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
+ OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
+ OPT_BOOLEAN( 0 , "track", &opts.track, "track"),
+ OPT_BOOLEAN('f', NULL, &opts.force, "force"),
+ OPT_BOOLEAN('m', NULL, &opts.merge, "merge"),
+ OPT_END(),
+ };
+
+ memset(&opts, 0, sizeof(opts));
+ memset(&new, 0, sizeof(new));
+
+ git_config(git_checkout_config);
+
+ opts.track = branch_track;
+
+ argc = parse_options(argc, argv, options, checkout_usage, 0);
+ if (argc) {
+ arg = argv[0];
+ if (get_sha1(arg, rev))
+ ;
+ else if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
+ new.name = arg;
+ setup_branch_path(&new);
+ if (resolve_ref(new.path, rev, 1, NULL))
+ new.commit = lookup_commit_reference(rev);
+ else
+ new.path = NULL;
+ parse_commit(new.commit);
+ source_tree = new.commit->tree;
+ argv++;
+ argc--;
+ } else if ((source_tree = parse_tree_indirect(rev))) {
+ argv++;
+ argc--;
+ }
+ }
+
+ if (argc && !strcmp(argv[0], "--")) {
+ argv++;
+ argc--;
+ }
+
+ if (!opts.new_branch && (opts.track != branch_track))
+ die("git checkout: --track and --no-track require -b");
+
+ if (opts.force && opts.merge)
+ die("git checkout: -f and -m are incompatible");
+
+ if (argc) {
+ const char **pathspec = get_pathspec(prefix, argv);
+ /* Checkout paths */
+ if (opts.new_branch || opts.force || opts.merge) {
+ if (argc == 1) {
+ die("git checkout: updating paths is incompatible with switching branches/forcing\nDid you intend to checkout '%s' which can not be resolved as commit?", argv[0]);
+ } else {
+ die("git checkout: updating paths is incompatible with switching branches/forcing");
+ }
+ }
+
+ if (source_tree)
+ read_tree_some(source_tree, pathspec);
+ else
+ read_cache();
+ return checkout_paths(pathspec);
+ }
+
+ if (new.name && !new.commit) {
+ die("Cannot switch branch to a non-commit.");
+ }
+
+ return switch_branches(&opts, &new);
+}