diff options
Diffstat (limited to 'libbuild2/file.cxx')
| -rw-r--r-- | libbuild2/file.cxx | 31 |
1 files changed, 23 insertions, 8 deletions
diff --git a/libbuild2/file.cxx b/libbuild2/file.cxx index 219a5f1..396b0fe 100644 --- a/libbuild2/file.cxx +++ b/libbuild2/file.cxx @@ -1698,20 +1698,35 @@ namespace build2 // Note that loading of the metadata is split into two steps, extraction and // parsing, because extraction also serves as validation that the executable // is runnable, what we expected, etc. In other words, we sometimes do the - // extraction without parsing. In this light it would have been more - // efficient for extract to return the running process with a pipe rather - // than the extracted data. But this would complicate the code quite a bit - // plus we don't expect the data to be large, typically. + // extraction without parsing. Actually, this seems to be no longer true but + // we do separate the two acts with some interleaving code (e.g., inserting + // the target). // // Also note that we do not check the export.metadata here leaving it to // the caller to do for both this case and export stub. // + // Finally, at first it may seem that caching the metadata is unnecessary + // since the target state itself serves as a cache (i.e., we try hard to + // avoid re-extracting the metadata). However, if there is no metadata, then + // we will re-run the extraction for every optional import. So we cache that + // case only. Note also that while this is only done during serial load, we + // still have to use MT-safe cache since it could be shared by multiple + // build contexts. + // + static global_cache<bool> metadata_cache; + static optional<string> extract_metadata (const process_path& pp, const string& key, bool opt, const location& loc) { + if (opt) + { + if (metadata_cache.find (pp.effect_string ())) + return nullopt; + } + // Note: to ease handling (think patching third-party code) we will always // specify the --build2-metadata option in this single-argument form. // @@ -1754,7 +1769,7 @@ namespace build2 ifdstream is (move (pr.in_ofd), ifdstream::badbit); // Note: no skip! // What are the odds that we will run some unrelated program which - // will keep writing to stdout until we run out of memory reading? + // will keep writing to stdout until we run out of memory reading it? // Apparently non-negligible (see GitHub issue #102). // string r; @@ -1839,7 +1854,10 @@ namespace build2 fail: if (opt) + { + metadata_cache.insert (pp.effect_string (), true); return nullopt; + } else throw failed (); } @@ -2683,10 +2701,7 @@ namespace build2 // the first import will determine the path). // if (r.second) - { r.first.as<exe> ().process_path (move (pp)); - r.second.unlock (); - } } // Save the metadata. Note that this happens during the load phase and |