git

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#include "git-compat-util.h"
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#include "abspath.h"
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#include "strbuf.h"
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/*
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 * Do not use this for inspecting *tracked* content.  When path is a
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 * symlink to a directory, we do not want to say it is a directory when
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 * dealing with tracked content in the working tree.
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 */
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int is_directory(const char *path)
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{
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	struct stat st;
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	return (!stat(path, &st) && S_ISDIR(st.st_mode));
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}
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/* removes the last path component from 'path' except if 'path' is root */
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static void strip_last_component(struct strbuf *path)
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{
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	size_t offset = offset_1st_component(path->buf);
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	size_t len = path->len;
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	/* Find start of the last component */
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	while (offset < len && !is_dir_sep(path->buf[len - 1]))
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		len--;
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	/* Skip sequences of multiple path-separators */
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	while (offset < len && is_dir_sep(path->buf[len - 1]))
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		len--;
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	strbuf_setlen(path, len);
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}
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/* get (and remove) the next component in 'remaining' and place it in 'next' */
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static void get_next_component(struct strbuf *next, struct strbuf *remaining)
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{
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	char *start = NULL;
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	char *end = NULL;
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	strbuf_reset(next);
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	/* look for the next component */
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	/* Skip sequences of multiple path-separators */
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	for (start = remaining->buf; is_dir_sep(*start); start++)
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		; /* nothing */
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	/* Find end of the path component */
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	for (end = start; *end && !is_dir_sep(*end); end++)
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		; /* nothing */
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	strbuf_add(next, start, end - start);
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	/* remove the component from 'remaining' */
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	strbuf_remove(remaining, 0, end - remaining->buf);
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}
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/* copies root part from remaining to resolved, canonicalizing it on the way */
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static void get_root_part(struct strbuf *resolved, struct strbuf *remaining)
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{
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	int offset = offset_1st_component(remaining->buf);
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	strbuf_reset(resolved);
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	strbuf_add(resolved, remaining->buf, offset);
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#ifdef GIT_WINDOWS_NATIVE
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	convert_slashes(resolved->buf);
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#endif
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	strbuf_remove(remaining, 0, offset);
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}
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/* We allow "recursive" symbolic links. Only within reason, though. */
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#ifndef MAXSYMLINKS
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#define MAXSYMLINKS 32
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#endif
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/*
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 * If set, any number of trailing components may be missing; otherwise, only one
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 * may be.
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 */
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#define REALPATH_MANY_MISSING (1 << 0)
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/* Should we die if there's an error? */
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#define REALPATH_DIE_ON_ERROR (1 << 1)
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static char *strbuf_realpath_1(struct strbuf *resolved, const char *path,
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			       int flags)
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{
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	struct strbuf remaining = STRBUF_INIT;
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	struct strbuf next = STRBUF_INIT;
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	struct strbuf symlink = STRBUF_INIT;
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	char *retval = NULL;
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	int num_symlinks = 0;
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	struct stat st;
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	if (!*path) {
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		if (flags & REALPATH_DIE_ON_ERROR)
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			die("The empty string is not a valid path");
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		else
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			goto error_out;
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	}
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	strbuf_addstr(&remaining, path);
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	get_root_part(resolved, &remaining);
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	if (!resolved->len) {
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		/* relative path; can use CWD as the initial resolved path */
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		if (strbuf_getcwd(resolved)) {
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			if (flags & REALPATH_DIE_ON_ERROR)
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				die_errno("unable to get current working directory");
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			else
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				goto error_out;
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		}
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	}
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	/* Iterate over the remaining path components */
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	while (remaining.len > 0) {
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		get_next_component(&next, &remaining);
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		if (next.len == 0) {
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			continue; /* empty component */
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		} else if (next.len == 1 && !strcmp(next.buf, ".")) {
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			continue; /* '.' component */
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		} else if (next.len == 2 && !strcmp(next.buf, "..")) {
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			/* '..' component; strip the last path component */
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			strip_last_component(resolved);
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			continue;
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		}
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		/* append the next component and resolve resultant path */
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		if (!is_dir_sep(resolved->buf[resolved->len - 1]))
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			strbuf_addch(resolved, '/');
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		strbuf_addbuf(resolved, &next);
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		if (lstat(resolved->buf, &st)) {
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			/* error out unless this was the last component */
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			if (errno != ENOENT ||
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			   (!(flags & REALPATH_MANY_MISSING) && remaining.len)) {
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				if (flags & REALPATH_DIE_ON_ERROR)
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					die_errno("Invalid path '%s'",
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						  resolved->buf);
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				else
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					goto error_out;
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			}
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		} else if (S_ISLNK(st.st_mode)) {
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			ssize_t len;
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			strbuf_reset(&symlink);
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			if (num_symlinks++ > MAXSYMLINKS) {
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				errno = ELOOP;
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				if (flags & REALPATH_DIE_ON_ERROR)
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					die("More than %d nested symlinks "
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					    "on path '%s'", MAXSYMLINKS, path);
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				else
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					goto error_out;
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			}
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			len = strbuf_readlink(&symlink, resolved->buf,
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					      st.st_size);
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			if (len < 0) {
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				if (flags & REALPATH_DIE_ON_ERROR)
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					die_errno("Invalid symlink '%s'",
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						  resolved->buf);
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				else
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					goto error_out;
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			}
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			if (is_absolute_path(symlink.buf)) {
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				/* absolute symlink; set resolved to root */
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				get_root_part(resolved, &symlink);
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			} else {
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				/*
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				 * relative symlink
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				 * strip off the last component since it will
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				 * be replaced with the contents of the symlink
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				 */
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				strip_last_component(resolved);
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			}
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			/*
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			 * if there are still remaining components to resolve
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			 * then append them to symlink
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			 */
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			if (remaining.len) {
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				strbuf_addch(&symlink, '/');
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				strbuf_addbuf(&symlink, &remaining);
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			}
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			/*
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			 * use the symlink as the remaining components that
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			 * need to be resolved
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			 */
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			strbuf_swap(&symlink, &remaining);
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		}
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	}
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	retval = resolved->buf;
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error_out:
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	strbuf_release(&remaining);
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	strbuf_release(&next);
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	strbuf_release(&symlink);
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	if (!retval)
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		strbuf_reset(resolved);
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	return retval;
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}
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/*
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 * Return the real path (i.e., absolute path, with symlinks resolved
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 * and extra slashes removed) equivalent to the specified path.  (If
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 * you want an absolute path but don't mind links, use
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 * absolute_path().)  Places the resolved realpath in the provided strbuf.
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 *
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 * The directory part of path (i.e., everything up to the last
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 * dir_sep) must denote a valid, existing directory, but the last
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 * component need not exist.  If die_on_error is set, then die with an
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 * informative error message if there is a problem.  Otherwise, return
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 * NULL on errors (without generating any output).
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 */
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char *strbuf_realpath(struct strbuf *resolved, const char *path,
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		      int die_on_error)
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{
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	return strbuf_realpath_1(resolved, path,
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				 die_on_error ? REALPATH_DIE_ON_ERROR : 0);
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}
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/*
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 * Just like strbuf_realpath, but allows an arbitrary number of path
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 * components to be missing.
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 */
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char *strbuf_realpath_forgiving(struct strbuf *resolved, const char *path,
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				int die_on_error)
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{
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	return strbuf_realpath_1(resolved, path,
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				 ((die_on_error ? REALPATH_DIE_ON_ERROR : 0) |
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				  REALPATH_MANY_MISSING));
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}
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char *real_pathdup(const char *path, int die_on_error)
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{
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	struct strbuf realpath = STRBUF_INIT;
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	char *retval = NULL;
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	if (strbuf_realpath(&realpath, path, die_on_error))
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		retval = strbuf_detach(&realpath, NULL);
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	strbuf_release(&realpath);
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	return retval;
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}
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/*
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 * Use this to get an absolute path from a relative one. If you want
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 * to resolve links, you should use strbuf_realpath.
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 */
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const char *absolute_path(const char *path)
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{
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	static struct strbuf sb = STRBUF_INIT;
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	strbuf_reset(&sb);
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	strbuf_add_absolute_path(&sb, path);
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	return sb.buf;
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}
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char *absolute_pathdup(const char *path)
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{
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	struct strbuf sb = STRBUF_INIT;
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	strbuf_add_absolute_path(&sb, path);
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	return strbuf_detach(&sb, NULL);
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}
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char *prefix_filename(const char *pfx, const char *arg)
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{
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	struct strbuf path = STRBUF_INIT;
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	size_t pfx_len = pfx ? strlen(pfx) : 0;
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	if (!pfx_len)
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		; /* nothing to prefix */
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	else if (is_absolute_path(arg))
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		pfx_len = 0;
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	else
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		strbuf_add(&path, pfx, pfx_len);
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	strbuf_addstr(&path, arg);
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#ifdef GIT_WINDOWS_NATIVE
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	convert_slashes(path.buf + pfx_len);
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#endif
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	return strbuf_detach(&path, NULL);
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}
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char *prefix_filename_except_for_dash(const char *pfx, const char *arg)
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{
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	if (!strcmp(arg, "-"))
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		return xstrdup(arg);
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	return prefix_filename(pfx, arg);
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}
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void strbuf_add_absolute_path(struct strbuf *sb, const char *path)
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{
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	if (!*path)
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		die("The empty string is not a valid path");
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	if (!is_absolute_path(path)) {
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		struct stat cwd_stat, pwd_stat;
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		size_t orig_len = sb->len;
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		char *cwd = xgetcwd();
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		char *pwd = getenv("PWD");
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		if (pwd && strcmp(pwd, cwd) &&
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		    !stat(cwd, &cwd_stat) &&
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		    (cwd_stat.st_dev || cwd_stat.st_ino) &&
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		    !stat(pwd, &pwd_stat) &&
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		    pwd_stat.st_dev == cwd_stat.st_dev &&
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		    pwd_stat.st_ino == cwd_stat.st_ino)
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			strbuf_addstr(sb, pwd);
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		else
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			strbuf_addstr(sb, cwd);
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		if (sb->len > orig_len && !is_dir_sep(sb->buf[sb->len - 1]))
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			strbuf_addch(sb, '/');
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		free(cwd);
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	}
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	strbuf_addstr(sb, path);
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}
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void strbuf_add_real_path(struct strbuf *sb, const char *path)
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{
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	if (sb->len) {
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		struct strbuf resolved = STRBUF_INIT;
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		strbuf_realpath(&resolved, path, 1);
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		strbuf_addbuf(sb, &resolved);
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		strbuf_release(&resolved);
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	} else
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		strbuf_realpath(sb, path, 1);
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}
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