Migrate source files into src/ directory

This change moves source files into a src/ directory,
and puts object files into an obj/ directory. The Makefile
and xcode project are updated accordingly.

Fixes #1866

src/path.h

@@ -0,0 +1,84 @@
+/** \file path.h
+
+  Directory utilities. This library contains functions for locating
+  configuration directories, for testing if a command with a given
+  name can be found in the PATH, and various other path-related
+  issues.
+*/
+
+#ifndef FISH_PATH_H
+#define FISH_PATH_H
+
+#include "env.h"
+
+/**
+   Return value for path_cdpath_get when locatied a rotten symlink
+ */
+#define EROTTEN 1
+
+/**
+   Returns the user configuration directory for fish. If the directory
+   or one of it's parents doesn't exist, they are first created.
+
+   \param path The directory as an out param
+   \return whether the directory was returned successfully
+*/
+bool path_get_config(wcstring &path);
+
+/**
+   Finds the full path of an executable. Returns YES if successful.
+
+   \param cmd The name of the executable.
+   \param output_or_NULL If non-NULL, store the full path.
+   \param vars The environment variables snapshot to use
+   \return 0 if the command can not be found, the path of the command otherwise. The result should be freed with free().
+*/
+bool path_get_path(const wcstring &cmd,
+                   wcstring *output_or_NULL,
+                   const env_vars_snapshot_t &vars = env_vars_snapshot_t::current());
+
+/**
+   Returns the full path of the specified directory, using the CDPATH
+   variable as a list of base directories for relative paths. The
+   returned string is allocated using halloc and the specified
+   context.
+
+   If no valid path is found, null is returned and errno is set to
+   ENOTDIR if at least one such path was found, but it did not point
+   to a directory, EROTTEN if a arotten symbolic link was found, or
+   ENOENT if no file of the specified name was found. If both a rotten
+   symlink and a file are found, it is undefined which error status
+   will be returned.
+
+   \param dir The name of the directory.
+   \param out_or_NULL If non-NULL, return the path to the resolved directory
+   \param wd The working directory, or NULL to use the default. The working directory should have a slash appended at the end.
+   \param vars The environment variable snapshot to use (for the CDPATH variable)
+   \return 0 if the command can not be found, the path of the command otherwise. The path should be free'd with free().
+*/
+bool path_get_cdpath(const wcstring &dir,
+                     wcstring *out_or_NULL,
+                     const wchar_t *wd = NULL,
+                     const env_vars_snapshot_t &vars = env_vars_snapshot_t::current());
+
+/** Returns whether the path can be used for an implicit cd command; if so, also returns the path by reference (if desired). This requires it to start with one of the allowed prefixes (., .., ~) and resolve to a directory. */
+bool path_can_be_implicit_cd(const wcstring &path,
+                             wcstring *out_path = NULL,
+                             const wchar_t *wd = NULL,
+                             const env_vars_snapshot_t &vars = env_vars_snapshot_t::current());
+
+/**
+   Remove double slashes and trailing slashes from a path,
+   e.g. transform foo//bar/ into foo/bar. The string is modified in-place.
+ */
+void path_make_canonical(wcstring &path);
+
+/** Check if two paths are equivalent, which means to ignore runs of multiple slashes (or trailing slashes) */
+bool paths_are_equivalent(const wcstring &p1, const wcstring &p2);
+
+bool path_is_valid(const wcstring &path, const wcstring &working_directory);
+
+/** Returns whether the two paths refer to the same file */
+bool paths_are_same_file(const wcstring &path1, const wcstring &path2);
+
+#endif