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Diffstat (limited to 'libbutl/default-options.mxx')
| -rw-r--r-- | libbutl/default-options.mxx | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/libbutl/default-options.mxx b/libbutl/default-options.mxx new file mode 100644 index 0000000..01d32c1 --- /dev/null +++ b/libbutl/default-options.mxx @@ -0,0 +1,115 @@ +// file : libbutl/default-options.mxx -*- C++ -*- +// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd +// license : MIT; see accompanying LICENSE file + +#ifndef __cpp_modules_ts +#pragma once +#endif + +#ifndef __cpp_lib_modules_ts +#include <utility> // move() +#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_dir; + }; + + 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). + // Throw std::system_error on the underlying OS error and pass through + // exceptions thrown by the options scanner/parser. + // + // Search order: + // + // - sys_dir + // - home_dir + // - start_dir and outer until home_dir or root (both excluding) + // + // Except for sys_dir, the options files are looked for in the .build2/ and + // .build2/local/ subdirectories of each directory. For sys_dir they are + // looked for in the directory itself (e.g., /etc/build2/). + // + // 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 definititevly conclude that the file is not remote; + // to be sure we would need to query the VCS or some such). + // + template <typename O, typename S, typename U> + default_options<O> + load_default_options (const optional<dir_path>& sys_dir, + const optional<dir_path>& home_dir, + const default_options_files&); + + // 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&&); +} + +#include <libbutl/default-options.txx> |