#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 ? old->object.sha1 : null_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, void *context)

{

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)

{

read_tree_recursive(tree, "", 0, 0, pathspec, update_some, NULL);

/* 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 skip_same_name(struct cache_entry *ce, int pos)

{

while ( pos < active_nr &&

!strcmp(active_cache[pos]->name, ce->name))

; /* skip */

return pos;

}

static int checkout_paths(struct tree *source_tree, const char **pathspec)

{

int pos;

struct checkout state;

static char *ps_matched;

unsigned char rev[20];

int flag;

struct commit *head;

int errs = 0;

int newfd;

struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));

newfd = hold_locked_index(lock_file, 1);

read_cache();

if (source_tree)

read_tree_some(source_tree, pathspec);

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;

/* Any unmerged paths? */

for (pos = 0; pos < active_nr; pos ) {

struct cache_entry *ce = active_cache[pos];

if (pathspec_match(pathspec, NULL, ce->name, 0)) {

if (!ce_stage(ce))

continue;

errs = 1;

error("path '%s' is unmerged", ce->name);

pos = skip_same_name(ce, pos) - 1;

}

}

if (errs)

return 1;

/* Now we are committed to check them out */

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)) {

if (!ce_stage(ce)) {

errs |= checkout_entry(ce, &state, NULL);

continue;

}

pos = skip_same_name(ce, pos) - 1;

}

}

if (write_cache(newfd, active_cache, active_nr) ||

commit_locked_index(lock_file))

die("unable to write new index file");

resolve_ref("HEAD", rev, 0, &flag);

head = lookup_commit_reference_gently(rev, 1);

errs |= post_checkout_hook(head, head, 0);

return errs;

}

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, NULL, NULL, 0, 0);

fprintf(stderr, "%s %s... %s\n", msg,

find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV), sb.buf);

strbuf_release(&sb);

}

struct checkout_opts {

};

static int reset_tree(struct tree *tree, struct checkout_opts *o, int worktree)

{

struct unpack_trees_options opts;

struct tree_desc tree_desc;

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

opts.head_idx = -1;

opts.update = worktree;

opts.skip_unmerged = !worktree;

opts.reset = 1;

opts.merge = 1;

opts.fn = oneway_merge;

opts.verbose_update = !o->quiet;

opts.src_index = &the_index;

opts.dst_index = &the_index;

parse_tree(tree);

init_tree_desc(&tree_desc, tree->buffer, tree->size);

switch (unpack_trees(1, &tree_desc, &opts)) {

case -2:

o->writeout_error = 1;

/*

* We return 0 nevertheless, as the index is all right

* and more importantly we have made best efforts to

* update paths in the work tree, and we cannot revert

* them.

*/

case 0:

return 0;

default:

return 128;

}

}

struct branch_info {

};

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_tree(new->commit->tree, opts, 1);

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;

topts.src_index = &the_index;

topts.dst_index = &the_index;

topts.msgs.not_uptodate_file = "You have local changes to '%s'; cannot switch branches.";

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.initial_checkout = is_cache_unborn();

topts.update = 1;

topts.merge = 1;

topts.gently = opts->merge && old->commit;

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);

ret = unpack_trees(2, trees, &topts);

if (ret == -1) {

/*

* 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;

/*

* Without old->commit, the below is the same as

* the two-tree unpack we already tried and failed.

*/

if (!old->commit)

return 1;

/* 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(NULL, NULL, 0);

work = write_tree_from_memory();

ret = reset_tree(new->commit->tree, opts, 1);

if (ret)

return ret;

merge_trees(new->commit->tree, work, old->commit->tree,

new->name, "local", &result);

ret = reset_tree(new->commit->tree, opts, 0);

if (ret)

return ret;

}

}

if (write_cache(newfd, active_cache, active_nr) ||

commit_locked_index(lock_file))

die("unable to write new index file");

if (!opts->force && !opts->quiet)

show_local_changes(&new->commit->object);

return 0;

}

static void report_tracking(struct branch_info *new)

{

struct strbuf sb = STRBUF_INIT;

struct branch *branch = branch_get(new->name);

if (!format_tracking_info(branch, &sb))

return;

fputs(sb.buf, stdout);

strbuf_release(&sb);

}

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->commit)

old_desc = sha1_to_hex(old->commit->object.sha1);

strbuf_addf(&msg, "checkout: moving from %s to %s",

old_desc ? old_desc : "(invalid)", 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);

}

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 we were on a detached HEAD, but we are now moving to

* a new commit, we want to mention the old commit once more

* to remind the user that it might be lost.

*/

if (!opts->quiet && !old.path && old.commit && new->commit != old.commit)

describe_detached_head("Previous HEAD position was", old.commit);

if (!old.commit && !opts->force) {

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);

ret = post_checkout_hook(old.commit, new->commit, 1);

return ret || opts->writeout_error;

}

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_SET_INT('t', "track", &opts.track, "track",

BRANCH_TRACK_EXPLICIT),

OPT_BOOLEAN('f', NULL, &opts.force, "force"),

OPT_BOOLEAN('m', NULL, &opts.merge, "merge"),

OPT_END(),

};

int has_dash_dash;

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

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

git_config(git_default_config, NULL);

opts.track = git_branch_track;

argc = parse_options(argc, argv, options, checkout_usage,

PARSE_OPT_KEEP_DASHDASH);

if (!opts.new_branch && (opts.track != git_branch_track))

die("git checkout: --track and --no-track require -b");

if (opts.force && opts.merge)

die("git checkout: -f and -m are incompatible");

/*

* case 1: git checkout <ref> -- [<paths>]

*

* <ref> must be a valid tree, everything after the '--' must be

* a path.

*

* case 2: git checkout -- [<paths>]

*

* everything after the '--' must be paths.

*

* case 3: git checkout <something> [<paths>]

*

* With no paths, if <something> is a commit, that is to

* switch to the branch or detach HEAD at it.

*

* Otherwise <something> shall not be ambiguous.

* - If it's *only* a reference, treat it like case (1).

* - If it's only a path, treat it like case (2).

* - else: fail.

*

*/

if (argc) {

if (!strcmp(argv[0], "--")) { /* case (2) */

argv ;

argc--;

goto no_reference;

}

arg = argv[0];

has_dash_dash = (argc > 1) && !strcmp(argv[1], "--");

if (get_sha1(arg, rev)) {

if (has_dash_dash) /* case (1) */

die("invalid reference: %s", arg);

goto no_reference; /* case (3 -> 2) */

}

/* we can't end up being in (2) anymore, eat the argument */

argv ;

argc--;

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;

} else

source_tree = parse_tree_indirect(rev);

if (!source_tree) /* case (1): want a tree */

die("reference is not a tree: %s", arg);

if (!has_dash_dash) {/* case (3 -> 1) */

/*

* Do not complain the most common case

* git checkout branch

* even if there happen to be a file called 'branch';

* it would be extremely annoying.

*/

if (argc)

verify_non_filename(NULL, arg);

}

else {

argv ;

argc--;

}

}

no_reference:

if (argc) {

const char **pathspec = get_pathspec(prefix, argv);

if (!pathspec)

die("invalid path specification");

/* 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");

}

}

return checkout_paths(source_tree, pathspec);

}

if (opts.new_branch) {

struct strbuf buf;

strbuf_init(&buf, 0);

strbuf_addstr(&buf, "refs/heads/");

strbuf_addstr(&buf, opts.new_branch);

if (!get_sha1(buf.buf, rev))

die("git checkout: branch %s already exists", opts.new_branch);

if (check_ref_format(buf.buf))

die("git checkout: we do not like '%s' as a branch name.", opts.new_branch);

strbuf_release(&buf);

}

if (new.name && !new.commit) {

die("Cannot switch branch to a non-commit.");

}

return switch_branches(&opts, &new);

}