diff options
Diffstat (limited to 'libbuild2/config/init.cxx')
| -rw-r--r-- | libbuild2/config/init.cxx | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/libbuild2/config/init.cxx b/libbuild2/config/init.cxx index 1513a47..9911670 100644 --- a/libbuild2/config/init.cxx +++ b/libbuild2/config/init.cxx @@ -28,6 +28,59 @@ namespace build2 void functions (function_map&); // functions.cxx + // Custom save function for config.config.environment. + // + // It tries to optimize the storage in subprojects by appending the + // difference (compared to the amalgamation's values) instead of storing + // the entire values. + // + static pair<names_view, const char*> + save_environment (const value& d, const value* b, names& storage) + { + if (b == nullptr) + return make_pair (reverse (d, storage), "="); + + // The plan is to iterator over environment variables adding those that + // are not in base to storage. There is, however, a complication: we may + // see multiple entries for the same variable and only the last entry + // should have effect. So we need to iterate in reverse and check if + // we've already seen this variable. + // + const strings& ds (d.as<strings> ()); + const strings& bs (b->as<strings> ()); + + for (auto i (ds.rbegin ()), e (ds.rend ()); i != e; ++i) + { + // Note that we must only consider variable names (up to first '=' if + // any). + // + const string& v (*i); + size_t p (v.find ('=')); + + // Check if we have already seen this variable. + // + if (find_if (ds.rbegin (), i, + [&v, p] (const string& v1) + { + return v.compare (0, p, v1, 0, v1.find ('=')) == 0; + }) != i) + continue; + + // Check if there is the same value in base. + // + auto j (find_if (bs.rbegin (), bs.rend (), + [&v, p] (const string& v1) + { + return v.compare (0, p, v1, 0, v1.find ('=')) == 0; + })); + + if (j == bs.rend () || *j != v) + storage.push_back (name (v)); + } + + return make_pair (names_view (storage), "+="); + } + void boot (scope& rs, const location&, module_boot_extra& extra) { @@ -96,6 +149,37 @@ namespace build2 auto& c_p (vp.insert<vector<pair<string, string>>> ( "config.config.persist", true /* ovr */, v_p)); + // Configuration environment variables. + // + // Environment variables used by tools (e.g., compilers), buildfiles + // (e.g., $getenv()), and the build system itself (e.g., to locate + // tools) in ways that affect the build result are in essence part of + // the project configuration. + // + // This variable allows storing environment variable overrides that + // should be applied to the environment when executing tools, etc., as + // part of a project build. Specifically, it contains a list of + // environment variable "sets" (<name>=<value>) and "unsets" (<name>). + // If multiple entries are specified for the same environment variable, + // the last entry has effect. For example: + // + // config.config.environment="LC_ALL=C LANG" + // + // Note that a subproject inherits overrides from its amalgamation (this + // semantics is the result of the way we optimize the storage of this + // variable in subproject's config.build; the thinking is that if a + // variable is not overridden by the subproject then it doesn't affect + // the build result and therefore it's irrelevant whether it has a value + // that came from the original environment of from the amalgamation + // override). + // + // Use the NULL or empty value to clear. + // + // @@ We could use =<name> as a "pass-through" instruction (e.g., if + // we need to use original value in subproject). + // + auto& c_e (vp.insert<strings> ("config.config.environment", true /* ovr */)); + // Only create the module if we are configuring, creating, or // disfiguring or if it was requested with config.config.module (useful // if we need to call $config.save() during other meta-operations). @@ -127,6 +211,9 @@ namespace build2 m.save_module ("import", INT32_MIN); m.save_variable (c_p, save_null_omitted); + m.save_variable (c_e, + save_null_omitted | save_empty_omitted | save_base, + &save_environment); } } |