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-rw-r--r--abspath.c180
1 files changed, 180 insertions, 0 deletions
diff --git a/abspath.c b/abspath.c
new file mode 100644
index 0000000000..2825de8591
--- /dev/null
+++ b/abspath.c
@@ -0,0 +1,180 @@
+#include "cache.h"
+
+/*
+ * Do not use this for inspecting *tracked* content. When path is a
+ * symlink to a directory, we do not want to say it is a directory when
+ * dealing with tracked content in the working tree.
+ */
+int is_directory(const char *path)
+{
+ struct stat st;
+ return (!stat(path, &st) && S_ISDIR(st.st_mode));
+}
+
+/* We allow "recursive" symbolic links. Only within reason, though. */
+#define MAXDEPTH 5
+
+/*
+ * Return the real path (i.e., absolute path, with symlinks resolved
+ * and extra slashes removed) equivalent to the specified path. (If
+ * you want an absolute path but don't mind links, use
+ * absolute_path().) The return value is a pointer to a static
+ * buffer.
+ *
+ * The input and all intermediate paths must be shorter than MAX_PATH.
+ * The directory part of path (i.e., everything up to the last
+ * dir_sep) must denote a valid, existing directory, but the last
+ * component need not exist. If die_on_error is set, then die with an
+ * informative error message if there is a problem. Otherwise, return
+ * NULL on errors (without generating any output).
+ *
+ * If path is our buffer, then return path, as it's already what the
+ * user wants.
+ */
+static const char *real_path_internal(const char *path, int die_on_error)
+{
+ static struct strbuf sb = STRBUF_INIT;
+ char *retval = NULL;
+
+ /*
+ * If we have to temporarily chdir(), store the original CWD
+ * here so that we can chdir() back to it at the end of the
+ * function:
+ */
+ struct strbuf cwd = STRBUF_INIT;
+
+ int depth = MAXDEPTH;
+ char *last_elem = NULL;
+ struct stat st;
+
+ /* We've already done it */
+ if (path == sb.buf)
+ return path;
+
+ if (!*path) {
+ if (die_on_error)
+ die("The empty string is not a valid path");
+ else
+ goto error_out;
+ }
+
+ strbuf_reset(&sb);
+ strbuf_addstr(&sb, path);
+
+ while (depth--) {
+ if (!is_directory(sb.buf)) {
+ char *last_slash = find_last_dir_sep(sb.buf);
+ if (last_slash) {
+ last_elem = xstrdup(last_slash + 1);
+ strbuf_setlen(&sb, last_slash - sb.buf + 1);
+ } else {
+ last_elem = xmemdupz(sb.buf, sb.len);
+ strbuf_reset(&sb);
+ }
+ }
+
+ if (sb.len) {
+ if (!cwd.len && strbuf_getcwd(&cwd)) {
+ if (die_on_error)
+ die_errno("Could not get current working directory");
+ else
+ goto error_out;
+ }
+
+ if (chdir(sb.buf)) {
+ if (die_on_error)
+ die_errno("Could not switch to '%s'",
+ sb.buf);
+ else
+ goto error_out;
+ }
+ }
+ if (strbuf_getcwd(&sb)) {
+ if (die_on_error)
+ die_errno("Could not get current working directory");
+ else
+ goto error_out;
+ }
+
+ if (last_elem) {
+ if (sb.len && !is_dir_sep(sb.buf[sb.len - 1]))
+ strbuf_addch(&sb, '/');
+ strbuf_addstr(&sb, last_elem);
+ free(last_elem);
+ last_elem = NULL;
+ }
+
+ if (!lstat(sb.buf, &st) && S_ISLNK(st.st_mode)) {
+ struct strbuf next_sb = STRBUF_INIT;
+ ssize_t len = strbuf_readlink(&next_sb, sb.buf, 0);
+ if (len < 0) {
+ if (die_on_error)
+ die_errno("Invalid symlink '%s'",
+ sb.buf);
+ else
+ goto error_out;
+ }
+ strbuf_swap(&sb, &next_sb);
+ strbuf_release(&next_sb);
+ } else
+ break;
+ }
+
+ retval = sb.buf;
+error_out:
+ free(last_elem);
+ if (cwd.len && chdir(cwd.buf))
+ die_errno("Could not change back to '%s'", cwd.buf);
+ strbuf_release(&cwd);
+
+ return retval;
+}
+
+const char *real_path(const char *path)
+{
+ return real_path_internal(path, 1);
+}
+
+const char *real_path_if_valid(const char *path)
+{
+ return real_path_internal(path, 0);
+}
+
+/*
+ * Use this to get an absolute path from a relative one. If you want
+ * to resolve links, you should use real_path.
+ */
+const char *absolute_path(const char *path)
+{
+ static struct strbuf sb = STRBUF_INIT;
+ strbuf_reset(&sb);
+ strbuf_add_absolute_path(&sb, path);
+ return sb.buf;
+}
+
+/*
+ * Unlike prefix_path, this should be used if the named file does
+ * not have to interact with index entry; i.e. name of a random file
+ * on the filesystem.
+ */
+const char *prefix_filename(const char *pfx, int pfx_len, const char *arg)
+{
+ static struct strbuf path = STRBUF_INIT;
+#ifndef GIT_WINDOWS_NATIVE
+ if (!pfx_len || is_absolute_path(arg))
+ return arg;
+ strbuf_reset(&path);
+ strbuf_add(&path, pfx, pfx_len);
+ strbuf_addstr(&path, arg);
+#else
+ /* don't add prefix to absolute paths, but still replace '\' by '/' */
+ strbuf_reset(&path);
+ if (is_absolute_path(arg))
+ pfx_len = 0;
+ else if (pfx_len)
+ strbuf_add(&path, pfx, pfx_len);
+ strbuf_addstr(&path, arg);
+ convert_slashes(path.buf + pfx_len);
+#endif
+ return path.buf;
+}