X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=plocate.cpp;h=63a927febe8091a5dbd7220ad6f0ebba925742ed;hb=db80346f0412329379cfde7a6aa0de8fd731ce4a;hp=a76c288a2bca86f0a11ebfec822d34721fa38335;hpb=c427ecd63267946d66cf15808ed507d4f94c3566;p=plocate diff --git a/plocate.cpp b/plocate.cpp index a76c288..63a927f 100644 --- a/plocate.cpp +++ b/plocate.cpp @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -45,18 +46,33 @@ bool use_debug = false; bool patterns_are_regex = false; bool use_extended_regex = false; int64_t limit_matches = numeric_limits::max(); +int64_t limit_left = numeric_limits::max(); + +steady_clock::time_point start; + +void apply_limit() +{ + if (--limit_left > 0) { + return; + } + dprintf("Done in %.1f ms, found %" PRId64 " matches.\n", + 1e3 * duration(steady_clock::now() - start).count(), limit_matches); + if (only_count) { + printf("%ld\n", limit_matches); + } + exit(0); +} class Serializer { public: - bool ready_to_print(int seq) { return next_seq == seq; } - void print_delayed(int seq, const vector msg); - void release_current(); + ~Serializer() { assert(limit_left <= 0 || pending.empty()); } + void print(uint64_t seq, uint64_t skip, const string msg); private: - int next_seq = 0; + uint64_t next_seq = 0; struct Element { - int seq; - vector msg; + uint64_t seq, skip; + string msg; bool operator<(const Element &other) const { @@ -66,28 +82,42 @@ private: priority_queue pending; }; -void Serializer::print_delayed(int seq, const vector msg) +void Serializer::print(uint64_t seq, uint64_t skip, const string msg) { - pending.push(Element{ seq, move(msg) }); -} + if (only_count) { + if (!msg.empty()) { + apply_limit(); + } + return; + } -void Serializer::release_current() -{ - ++next_seq; + if (next_seq != seq) { + pending.push(Element{ seq, skip, move(msg) }); + return; + } + + if (!msg.empty()) { + if (print_nul) { + printf("%s%c", msg.c_str(), 0); + } else { + printf("%s\n", msg.c_str()); + } + apply_limit(); + } + next_seq += skip; // See if any delayed prints can now be dealt with. while (!pending.empty() && pending.top().seq == next_seq) { - if (limit_matches-- <= 0) - return; - for (const string &msg : pending.top().msg) { + if (!pending.top().msg.empty()) { if (print_nul) { - printf("%s%c", msg.c_str(), 0); + printf("%s%c", pending.top().msg.c_str(), 0); } else { - printf("%s\n", msg.c_str()); + printf("%s\n", pending.top().msg.c_str()); } + apply_limit(); } + next_seq += pending.top().skip; pending.pop(); - ++next_seq; } } @@ -112,27 +142,83 @@ bool matches(const Needle &needle, const char *haystack) } } -bool has_access(const char *filename, - unordered_map *access_rx_cache) +class AccessRXCache { +public: + AccessRXCache(IOUringEngine *engine) + : engine(engine) {} + void check_access(const char *filename, bool allow_async, function cb); + +private: + unordered_map cache; + struct PendingStat { + string filename; + function cb; + }; + map> pending_stats; + IOUringEngine *engine; +}; + +void AccessRXCache::check_access(const char *filename, bool allow_async, function cb) { - const char *end = strchr(filename + 1, '/'); - while (end != nullptr) { - string parent_path(filename, end); - auto it = access_rx_cache->find(parent_path); - bool ok; - if (it == access_rx_cache->end()) { - ok = access(parent_path.c_str(), R_OK | X_OK) == 0; - access_rx_cache->emplace(move(parent_path), ok); - } else { - ok = it->second; + if (engine == nullptr || !engine->get_supports_stat()) { + allow_async = false; + } + + for (const char *end = strchr(filename + 1, '/'); end != nullptr; end = strchr(end + 1, '/')) { + string parent_path(filename, end - filename); // string_view from C++20. + auto cache_it = cache.find(parent_path); + if (cache_it != cache.end()) { + // Found in the cache. + if (!cache_it->second) { + cb(false); + return; + } + continue; + } + + if (!allow_async) { + bool ok = access(parent_path.c_str(), R_OK | X_OK) == 0; + cache.emplace(parent_path, ok); + if (!ok) { + cb(false); + return; + } + continue; } - if (!ok) { - return false; + + // We want to call access(), but it could block on I/O. io_uring doesn't support + // access(), but we can do a dummy asynchonous statx() to populate the kernel's cache, + // which nearly always makes the next access() instantaneous. + + // See if there's already a pending stat that matches this, + // or is a subdirectory. + auto it = pending_stats.lower_bound(parent_path); + if (it != pending_stats.end() && it->first.size() >= parent_path.size() && + it->first.compare(0, parent_path.size(), parent_path) == 0) { + it->second.emplace_back(PendingStat{ filename, move(cb) }); + } else { + it = pending_stats.emplace(filename, vector{}).first; + engine->submit_stat(filename, [this, it, filename{ strdup(filename) }, cb{ move(cb) }] { + // The stat returned, so now do the actual access() calls. + // All of them should be in cache, so don't fire off new statx() + // calls during that check. + check_access(filename, /*allow_async=*/false, move(cb)); + free(filename); + + // Call all others that waited for the same stat() to finish. + // They may fire off new stat() calls if needed. + vector pending = move(it->second); + pending_stats.erase(it); + for (PendingStat &ps : pending) { + check_access(ps.filename.c_str(), /*allow_async=*/true, move(ps.cb)); + } + }); } - end = strchr(end + 1, '/'); + return; // The rest will happen in async context. } - return true; + // Passed all checks. + cb(true); } class Corpus { @@ -217,12 +303,10 @@ size_t Corpus::get_num_filename_blocks() const return hdr.num_docids; } -uint64_t scan_file_block(const vector &needles, string_view compressed, - unordered_map *access_rx_cache, int seq, - Serializer *serializer) +void scan_file_block(const vector &needles, string_view compressed, + AccessRXCache *access_rx_cache, uint64_t seq, Serializer *serializer, + size_t *matched) { - uint64_t matched = 0; - unsigned long long uncompressed_len = ZSTD_getFrameContentSize(compressed.data(), compressed.size()); if (uncompressed_len == ZSTD_CONTENTSIZE_UNKNOWN || uncompressed_len == ZSTD_CONTENTSIZE_ERROR) { fprintf(stderr, "ZSTD_getFrameContentSize() failed\n"); @@ -240,9 +324,23 @@ uint64_t scan_file_block(const vector &needles, string_view compressed, } block[block.size() - 1] = '\0'; - bool immediate_print = (serializer == nullptr || serializer->ready_to_print(seq)); - vector delayed; + auto test_candidate = [&](const char *filename, uint64_t local_seq, uint64_t next_seq) { + access_rx_cache->check_access(filename, /*allow_async=*/true, [matched, serializer, local_seq, next_seq, filename{ strdup(filename) }](bool ok) { + if (ok) { + ++*matched; + serializer->print(local_seq, next_seq - local_seq, filename); + } else { + serializer->print(local_seq, next_seq - local_seq, ""); + } + free(filename); + }); + }; + + // We need to know the next sequence number before inserting into Serializer, + // so always buffer one candidate. + const char *pending_candidate = nullptr; + uint64_t local_seq = seq << 32; for (const char *filename = block.data(); filename != block.data() + block.size(); filename += strlen(filename) + 1) { @@ -253,42 +351,30 @@ uint64_t scan_file_block(const vector &needles, string_view compressed, break; } } - if (found && has_access(filename, access_rx_cache)) { - if (limit_matches-- <= 0) - break; - ++matched; - if (only_count) - continue; - if (immediate_print) { - if (print_nul) { - printf("%s%c", filename, 0); - } else { - printf("%s\n", filename); - } - } else { - delayed.push_back(filename); + if (found) { + if (pending_candidate != nullptr) { + test_candidate(pending_candidate, local_seq, local_seq + 1); + ++local_seq; } + pending_candidate = filename; } } - if (serializer != nullptr && !only_count) { - if (immediate_print) { - serializer->release_current(); - } else { - serializer->print_delayed(seq, move(delayed)); - } + if (pending_candidate == nullptr) { + serializer->print(seq << 32, 1ULL << 32, ""); + } else { + test_candidate(pending_candidate, local_seq, (seq + 1) << 32); } - return matched; } size_t scan_docids(const vector &needles, const vector &docids, const Corpus &corpus, IOUringEngine *engine) { Serializer docids_in_order; - unordered_map access_rx_cache; + AccessRXCache access_rx_cache(engine); uint64_t matched = 0; for (size_t i = 0; i < docids.size(); ++i) { uint32_t docid = docids[i]; corpus.get_compressed_filename_block(docid, [i, &matched, &needles, &access_rx_cache, &docids_in_order](string_view compressed) { - matched += scan_file_block(needles, compressed, &access_rx_cache, i, &docids_in_order); + scan_file_block(needles, compressed, &access_rx_cache, i, &docids_in_order, &matched); }); } engine->finish(); @@ -298,9 +384,10 @@ size_t scan_docids(const vector &needles, const vector &docids // We do this sequentially, as it's faster than scattering // a lot of I/O through io_uring and hoping the kernel will // coalesce it plus readahead for us. -uint64_t scan_all_docids(const vector &needles, int fd, const Corpus &corpus, IOUringEngine *engine) +uint64_t scan_all_docids(const vector &needles, int fd, const Corpus &corpus) { - unordered_map access_rx_cache; + AccessRXCache access_rx_cache(nullptr); + Serializer serializer; // Mostly dummy; handles only the limit. uint32_t num_blocks = corpus.get_num_filename_blocks(); unique_ptr offsets(new uint64_t[num_blocks + 1]); complete_pread(fd, offsets.get(), (num_blocks + 1) * sizeof(uint64_t), corpus.offset_for_block(0)); @@ -317,9 +404,7 @@ uint64_t scan_all_docids(const vector &needles, int fd, const Corpus &co for (uint32_t docid = io_docid; docid < last_docid; ++docid) { size_t relative_offset = offsets[docid] - offsets[io_docid]; size_t len = offsets[docid + 1] - offsets[docid]; - matched += scan_file_block(needles, { &compressed[relative_offset], len }, &access_rx_cache, 0, nullptr); - if (limit_matches <= 0) - return matched; + scan_file_block(needles, { &compressed[relative_offset], len }, &access_rx_cache, docid, &serializer, &matched); } } return matched; @@ -386,7 +471,7 @@ void do_search_file(const vector &needles, const char *filename) exit(EXIT_FAILURE); } - steady_clock::time_point start __attribute__((unused)) = steady_clock::now(); + start = steady_clock::now(); if (access("/", R_OK | X_OK)) { // We can't find anything, no need to bother... return; @@ -431,7 +516,7 @@ void do_search_file(const vector &needles, const char *filename) // (We could have searched through all trigrams that matched // the pattern and done a union of them, but that's a lot of // work for fairly unclear gain.) - uint64_t matched = scan_all_docids(needles, fd, corpus, &engine); + uint64_t matched = scan_all_docids(needles, fd, corpus); if (only_count) { printf("%" PRId64 "\n", matched); } @@ -662,7 +747,7 @@ int main(int argc, char **argv) break; case 'l': case 'n': - limit_matches = atoll(optarg); + limit_matches = limit_left = atoll(optarg); if (limit_matches <= 0) { fprintf(stderr, "Error: limit must be a strictly positive number.\n"); exit(1);