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// file : libbutl/default-options.mxx -*- C++ -*-
// license : MIT; see accompanying LICENSE file
#ifndef __cpp_modules_ts
#pragma once
#endif
#ifndef __cpp_lib_modules_ts
#include <vector>
#include <utility> // move(), forward(), make_pair()
#include <algorithm> // reverse()
#include <system_error>
#endif
// Other includes.
#ifdef __cpp_modules_ts
export module butl.default_options;
#ifdef __cpp_lib_modules_ts
import std.core;
#endif
import butl.path;
import butl.optional;
import butl.small_vector;
import butl.git;
import butl.filesystem;
#else
#include <libbutl/path.mxx>
#include <libbutl/optional.mxx>
#include <libbutl/small-vector.mxx>
#include <libbutl/git.mxx>
#include <libbutl/filesystem.mxx>
#endif
#include <libbutl/export.hxx>
LIBBUTL_MODEXPORT namespace butl
{
// Default options files helper implementation.
//
struct default_options_files
{
small_vector<path, 2> files;
optional<dir_path> start;
};
template <typename O>
struct default_options_entry
{
path file;
O options;
bool remote;
};
template <typename O>
using default_options = small_vector<default_options_entry<O>, 4>;
// Search for and load (using scanner S and parsing in the U::fail mode for
// both options and arguments) the specified list of options files in the
// specified directories returning a vector of option class instances (O).
// Pass each default options file path to the specified function prior to
// load (can be used for tracing, etc). The function signature is:
//
// void (const path&, bool remote, bool overwrite)
//
// Note that the function may be called for the same file twice if it was
// later discovered that it is in fact remote. In the second call the
// overwrite flag will be true.
//
// Throw `pair<path, system_error>` on the underlying OS error with the
// first half referring the filesystem entry the error relates to and pass
// through exceptions thrown by the options scanner/parser.
//
// Search order:
//
// - sys_dir
// - home_dir
// - extra_dir (can also be handled during the start/outer traversal)
// - start_dir and outer until home_dir or root (both excluding)
//
// Except for sys_dir and extra_dir, the options files are looked for in the
// .build2/ and .build2/local/ subdirectories of each directory. For
// sys_dir and extra_dir they are looked for in the directory itself (e.g.,
// /etc/build2/).
//
// Note that the search is stopped at the directory containing a file with
// --no-default-options.
//
// Also note that all the directories should be absolute and normalized.
//
// The presence of the .git filesystem entry causes the options files in
// this directory and any of its subdirectories to be considered remote
// (note that in the current implementation this is the case even for files
// from the .build2/local/ subdirectory since the mere location is not a
// sufficient ground to definitively conclude that the file is not remote;
// to be sure we would need to query the VCS or some such).
//
// Note that the extra directory options files are never considered remote.
//
template <typename O, typename S, typename U, typename F>
default_options<O>
load_default_options (const optional<dir_path>& sys_dir,
const optional<dir_path>& home_dir,
const optional<dir_path>& extra_dir,
const default_options_files&,
F&&);
// Merge the default options and the command line options.
//
// Note that this is the default implementation and in some cases you may
// want to provide an options class-specific version that verifies/sanitizes
// the default options (e.g., you may not want to allow certain options to
// be specified in the default options files) or warns/prompts about
// potentially dangerous options if they came from the remote options files.
//
template <typename O>
O
merge_default_options (const default_options<O>&, const O& cmd_ops);
// As above but pass each default option to the specified function prior to
// merging. The function signature is:
//
// void (const default_options_entry<O>&, const O& cmd_ops)
//
// This version can be used to verify the default options. For example, you
// may want to disallow certain options from being specified in the default
// options files.
//
template <typename O, typename F>
O
merge_default_options (const default_options<O>&, const O&, F&&);
// Find a common start (parent) directory stopping at home or root
// (excluding).
//
LIBBUTL_SYMEXPORT optional<dir_path>
default_options_start (const optional<dir_path>& home_dir,
const std::vector<dir_path>&);
}
#include <libbutl/default-options.ixx>
#include <libbutl/default-options.txx>
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