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![Junio C Hamano](/assets/img/avatar_default.png)
This allows "git checkout v1.4.3" to dissociate the HEAD of repository from any branch. After this point, "git branch" starts reporting that you are not on any branch. You can go back to an existing branch by saying "git checkout master", for example. This is still experimental. While I think it makes sense to allow commits on top of detached HEAD, it is rather dangerous unless you are careful in the current form. Next "git checkout master" will obviously lose what you have done, so we might want to require "git checkout -f" out of a detached HEAD if we find that the HEAD commit is not an ancestor of any other branches. There is no such safety valve implemented right now. On the other hand, the reason the user did not start the ad-hoc work on a new branch with "git checkout -b" was probably because the work was of a throw-away nature, so the convenience of not having that safety valve might be even better. The user, after accumulating some commits on top of a detached HEAD, can always create a new branch with "git checkout -b" not to lose useful work done while the HEAD was detached. We'll see. Signed-off-by: Junio C Hamano <junkio@cox.net>
271 lines
6.1 KiB
C
271 lines
6.1 KiB
C
#include "cache.h"
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const char *prefix_path(const char *prefix, int len, const char *path)
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{
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const char *orig = path;
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for (;;) {
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char c;
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if (*path != '.')
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break;
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c = path[1];
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/* "." */
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if (!c) {
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path++;
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break;
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}
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/* "./" */
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if (c == '/') {
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path += 2;
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continue;
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}
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if (c != '.')
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break;
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c = path[2];
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if (!c)
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path += 2;
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else if (c == '/')
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path += 3;
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else
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break;
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/* ".." and "../" */
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/* Remove last component of the prefix */
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do {
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if (!len)
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die("'%s' is outside repository", orig);
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len--;
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} while (len && prefix[len-1] != '/');
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continue;
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}
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if (len) {
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int speclen = strlen(path);
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char *n = xmalloc(speclen + len + 1);
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memcpy(n, prefix, len);
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memcpy(n + len, path, speclen+1);
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path = n;
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}
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return path;
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}
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/*
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* Unlike prefix_path, this should be used if the named file does
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* not have to interact with index entry; i.e. name of a random file
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* on the filesystem.
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*/
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const char *prefix_filename(const char *pfx, int pfx_len, const char *arg)
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{
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static char path[PATH_MAX];
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if (!pfx || !*pfx || arg[0] == '/')
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return arg;
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memcpy(path, pfx, pfx_len);
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strcpy(path + pfx_len, arg);
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return path;
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}
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/*
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* Verify a filename that we got as an argument for a pathspec
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* entry. Note that a filename that begins with "-" never verifies
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* as true, because even if such a filename were to exist, we want
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* it to be preceded by the "--" marker (or we want the user to
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* use a format like "./-filename")
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*/
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void verify_filename(const char *prefix, const char *arg)
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{
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const char *name;
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struct stat st;
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if (*arg == '-')
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die("bad flag '%s' used after filename", arg);
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name = prefix ? prefix_filename(prefix, strlen(prefix), arg) : arg;
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if (!lstat(name, &st))
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return;
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if (errno == ENOENT)
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die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
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"Use '--' to separate paths from revisions", arg);
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die("'%s': %s", arg, strerror(errno));
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}
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/*
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* Opposite of the above: the command line did not have -- marker
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* and we parsed the arg as a refname. It should not be interpretable
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* as a filename.
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*/
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void verify_non_filename(const char *prefix, const char *arg)
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{
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const char *name;
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struct stat st;
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if (*arg == '-')
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return; /* flag */
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name = prefix ? prefix_filename(prefix, strlen(prefix), arg) : arg;
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if (!lstat(name, &st))
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die("ambiguous argument '%s': both revision and filename\n"
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"Use '--' to separate filenames from revisions", arg);
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if (errno != ENOENT)
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die("'%s': %s", arg, strerror(errno));
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}
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const char **get_pathspec(const char *prefix, const char **pathspec)
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{
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const char *entry = *pathspec;
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const char **p;
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int prefixlen;
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if (!prefix && !entry)
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return NULL;
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if (!entry) {
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static const char *spec[2];
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spec[0] = prefix;
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spec[1] = NULL;
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return spec;
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}
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/* Otherwise we have to re-write the entries.. */
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p = pathspec;
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prefixlen = prefix ? strlen(prefix) : 0;
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do {
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*p = prefix_path(prefix, prefixlen, entry);
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} while ((entry = *++p) != NULL);
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return (const char **) pathspec;
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}
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/*
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* Test if it looks like we're at a git directory.
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* We want to see:
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*
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* - either a objects/ directory _or_ the proper
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* GIT_OBJECT_DIRECTORY environment variable
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* - a refs/ directory
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* - either a HEAD symlink or a HEAD file that is formatted as
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* a proper "ref:", or a regular file HEAD that has a properly
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* formatted sha1 object name.
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*/
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static int is_git_directory(const char *suspect)
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{
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char path[PATH_MAX];
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size_t len = strlen(suspect);
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strcpy(path, suspect);
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if (getenv(DB_ENVIRONMENT)) {
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if (access(getenv(DB_ENVIRONMENT), X_OK))
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return 0;
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}
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else {
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strcpy(path + len, "/objects");
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if (access(path, X_OK))
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return 0;
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}
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strcpy(path + len, "/refs");
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if (access(path, X_OK))
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return 0;
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strcpy(path + len, "/HEAD");
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if (validate_headref(path))
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return 0;
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return 1;
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}
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const char *setup_git_directory_gently(int *nongit_ok)
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{
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static char cwd[PATH_MAX+1];
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const char *gitdirenv;
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int len, offset;
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/*
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* If GIT_DIR is set explicitly, we're not going
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* to do any discovery, but we still do repository
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* validation.
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*/
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gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
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if (gitdirenv) {
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if (PATH_MAX - 40 < strlen(gitdirenv))
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die("'$%s' too big", GIT_DIR_ENVIRONMENT);
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if (is_git_directory(gitdirenv))
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return NULL;
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if (nongit_ok) {
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*nongit_ok = 1;
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return NULL;
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}
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die("Not a git repository: '%s'", gitdirenv);
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}
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if (!getcwd(cwd, sizeof(cwd)) || cwd[0] != '/')
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die("Unable to read current working directory");
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offset = len = strlen(cwd);
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for (;;) {
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if (is_git_directory(".git"))
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break;
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chdir("..");
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do {
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if (!offset) {
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if (is_git_directory(cwd)) {
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if (chdir(cwd))
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die("Cannot come back to cwd");
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setenv(GIT_DIR_ENVIRONMENT, cwd, 1);
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return NULL;
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}
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if (nongit_ok) {
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if (chdir(cwd))
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die("Cannot come back to cwd");
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*nongit_ok = 1;
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return NULL;
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}
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die("Not a git repository");
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}
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} while (cwd[--offset] != '/');
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}
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if (offset == len)
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return NULL;
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/* Make "offset" point to past the '/', and add a '/' at the end */
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offset++;
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cwd[len++] = '/';
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cwd[len] = 0;
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return cwd + offset;
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}
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int git_config_perm(const char *var, const char *value)
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{
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if (value) {
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if (!strcmp(value, "umask"))
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return PERM_UMASK;
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if (!strcmp(value, "group"))
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return PERM_GROUP;
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if (!strcmp(value, "all") ||
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!strcmp(value, "world") ||
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!strcmp(value, "everybody"))
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return PERM_EVERYBODY;
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}
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return git_config_bool(var, value);
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}
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int check_repository_format_version(const char *var, const char *value)
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{
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if (strcmp(var, "core.repositoryformatversion") == 0)
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repository_format_version = git_config_int(var, value);
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else if (strcmp(var, "core.sharedrepository") == 0)
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shared_repository = git_config_perm(var, value);
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return 0;
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}
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int check_repository_format(void)
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{
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git_config(check_repository_format_version);
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if (GIT_REPO_VERSION < repository_format_version)
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die ("Expected git repo version <= %d, found %d",
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GIT_REPO_VERSION, repository_format_version);
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return 0;
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}
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const char *setup_git_directory(void)
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{
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const char *retval = setup_git_directory_gently(NULL);
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check_repository_format();
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return retval;
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}
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