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// file : libbuild2/config/init.cxx -*- C++ -*-
// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
// license : MIT; see accompanying LICENSE file
#include <libbuild2/config/init.hxx>
#include <libbuild2/file.hxx>
#include <libbuild2/rule.hxx>
#include <libbuild2/lexer.hxx>
#include <libbuild2/scope.hxx>
#include <libbuild2/context.hxx>
#include <libbuild2/function.hxx>
#include <libbuild2/filesystem.hxx> // exists()
#include <libbuild2/diagnostics.hxx>
#include <libbuild2/config/module.hxx>
#include <libbuild2/config/utility.hxx>
#include <libbuild2/config/operation.hxx>
using namespace std;
using namespace butl;
namespace build2
{
namespace config
{
void
functions (function_map&); // functions.cxx
bool
boot (scope& rs, const location&, unique_ptr<module_base>& mod)
{
tracer trace ("config::boot");
context& ctx (rs.ctx);
l5 ([&]{trace << "for " << rs;});
auto& vp (rs.ctx.var_pool.rw (rs));
// While config.import (see below) could theoretically be specified in a
// buildfile, config.export is expected to always be specified as a
// command line override.
//
// Note: must be entered during bootstrap since we need it in
// configure_execute().
//
vp.insert<path> ("config.export", true /* ovr */);
// Only create the module if we are configuring or creating or if it was
// forced with config.module (useful if we need to call $config.export()
// during other meta-operations).
//
// Detecting the former (configuring/creating) is a bit tricky since the
// build2 core may not yet know if this is the case. But we know.
//
auto& c_m (vp.insert<bool> ("config.module", false /*ovr*/));
const string& mname (ctx.current_mname);
const string& oname (ctx.current_oname);
if (( mname == "configure" || mname == "create") ||
(mname.empty () && (oname == "configure" || oname == "create")) ||
cast_false<bool> (rs.vars[c_m]))
{
unique_ptr<module> m (new module);
// Adjust priority for the import pseudo-module so that
// config.import.* values come first in config.build.
//
m->save_module ("import", INT32_MIN);
mod = move (m);
}
// Register the config function family if this is the first instance of
// the config module.
//
if (!function_family::defined (ctx.functions, "config"))
functions (ctx.functions);
// Register meta-operations. Note that we don't register create_id
// since it will be pre-processed into configure.
//
rs.insert_meta_operation (configure_id, mo_configure);
rs.insert_meta_operation (disfigure_id, mo_disfigure);
return true; // Initialize first (load config.build).
}
bool
init (scope& rs,
scope&,
const location& l,
unique_ptr<module_base>&,
bool first,
bool,
const variable_map& config_hints)
{
tracer trace ("config::init");
if (!first)
{
warn (l) << "multiple config module initializations";
return true;
}
l5 ([&]{trace << "for " << rs;});
assert (config_hints.empty ()); // We don't known any hints.
// Note that the config.<name>* variables belong to the module <name>.
// So the only "special" variables we can allocate in config.* are
// config.config.*, names that have been "gifted" to us by other modules
// (like config.version) as well as names that we have reserved to not
// be valid module names (build, import, export).
//
auto& vp (rs.ctx.var_pool.rw (rs));
auto& c_v (vp.insert<uint64_t> ("config.version", false /*ovr*/));
auto& c_i (vp.insert<paths> ("config.import", true /* ovr */));
// Load config.build if one exists followed by extra files specified in
// config.import (we don't need to worry about disfigure since we will
// never be init'ed).
//
auto load_config = [&rs, &c_v] (const path& f, const location& l)
{
// Check the config version. We assume that old versions cannot
// understand new configs and new versions are incompatible with old
// configs.
//
// We extract the value manually instead of loading and then checking
// in order to be able to fixup/migrate the file which we may want to
// do in the future.
//
// This is tricky for stdin since we cannot reopen it (or put more
// than one character back). So what we are going to do is continue
// reading after extracting the variable. One side effect of this is
// that we won't have the config.version variable entered in the scope
// but that is harmless (we could do it manually if necessary).
//
ifdstream ifs;
lexer lex (open_file_or_stdin (f, ifs), f);
// Assume missing version is 0.
//
auto p (extract_variable (rs.ctx, lex, c_v));
uint64_t v (p.second ? cast<uint64_t> (p.first) : 0);
if (v != module::version)
fail (l) << "incompatible config file " << f <<
info << "config file version " << v
<< (p.second ? "" : " (missing)") <<
info << "config module version " << module::version <<
info << "consider reconfiguring " << project (rs) << '@'
<< rs.out_path ();
source (rs, rs, lex);
};
{
path f (config_file (rs));
if (exists (f))
load_config (f, l);
}
if (lookup l = rs[c_i])
{
// Only load files that were specified on our root scope as well as
// global overrides. This way we can use our override "positioning"
// machinery (i.e., where the override applies) to decide where the
// extra config is loaded. The resulting semantics feels quite natural
// and consistent with command line variable overrides:
//
// b config.import=.../config.build # outermost amalgamation
// b ./config.import=.../config.build # this project
// b !config.import=.../config.build # every project
//
if (l.belongs (rs) || l.belongs (rs.ctx.global_scope))
{
for (const path& f: cast<paths> (l))
load_config (f, location (&f));
}
}
// Register alias and fallback rule for the configure meta-operation.
//
// We need this rule for out-of-any-project dependencies (e.g.,
// libraries imported from /usr/lib). We are registring it on the
// global scope similar to builtin rules.
//
{
auto& r (rs.global_scope ().rules);
r.insert<mtime_target> (
configure_id, 0, "config.file", file_rule::instance);
}
{
auto& r (rs.rules);
//@@ outer
r.insert<alias> (configure_id, 0, "config.alias", alias_rule::instance);
// This allows a custom configure rule while doing nothing by default.
//
r.insert<target> (configure_id, 0, "config", noop_rule::instance);
r.insert<file> (configure_id, 0, "config.file", noop_rule::instance);
}
return true;
}
static const module_functions mod_functions[] =
{
{"config", &boot, &init},
{nullptr, nullptr, nullptr}
};
const module_functions*
build2_config_load ()
{
// Initialize the config entry points in the build system core.
//
config_save_variable = &save_variable;
config_preprocess_create = &preprocess_create;
return mod_functions;
}
}
}
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