]> git.sesse.net Git - plocate/blobdiff - database-builder.cpp
Release plocate 1.1.22.
[plocate] / database-builder.cpp
index 6e792be450202767b55eec08c869cae3b242b4a9..f9dfb715391b3be7c4c521710d48f86b3b10795b 100644 (file)
@@ -5,6 +5,9 @@
 
 #include <algorithm>
 #include <assert.h>
+#ifdef HAS_ENDIAN_H
+#include <endian.h>
+#endif
 #include <fcntl.h>
 #include <string.h>
 #include <string_view>
@@ -26,29 +29,19 @@ constexpr unsigned num_overflow_slots = 16;
 
 string zstd_compress(const string &src, ZSTD_CDict *cdict, string *tempbuf);
 
-static inline uint32_t read_unigram(const string_view s, size_t idx)
-{
-       if (idx < s.size()) {
-               return (unsigned char)s[idx];
-       } else {
-               return 0;
-       }
-}
-
-static inline uint32_t read_trigram(const string_view s, size_t start)
-{
-       return read_unigram(s, start) |
-               (read_unigram(s, start + 1) << 8) |
-               (read_unigram(s, start + 2) << 16);
-}
-
 class PostingListBuilder {
 public:
        inline void add_docid(uint32_t docid);
+       inline void add_first_docid(uint32_t docid);
        void finish();
 
-       string encoded;
-       size_t num_docids = 0;
+       vector<unsigned char> encoded;
+       size_t get_num_docids() const
+       {
+               // Updated only when we flush, so check that we're finished.
+               assert(pending_deltas.empty());
+               return num_docids;
+       }
 
 private:
        void write_header(uint32_t docid);
@@ -56,7 +49,8 @@ private:
 
        vector<uint32_t> pending_deltas;
 
-       uint32_t last_block_end, last_docid = -1;
+       uint32_t num_docids = 0;  // Should be size_t, except the format only supports 2^32 docids per posting list anyway.
+       uint32_t last_docid = -1;
 };
 
 void PostingListBuilder::add_docid(uint32_t docid)
@@ -66,22 +60,20 @@ void PostingListBuilder::add_docid(uint32_t docid)
                return;
        }
 
-       if (num_docids == 0) {
-               // Very first docid.
-               write_header(docid);
-               ++num_docids;
-               last_block_end = last_docid = docid;
-               return;
-       }
-
        pending_deltas.push_back(docid - last_docid - 1);
        last_docid = docid;
        if (pending_deltas.size() == 128) {
                append_block();
                pending_deltas.clear();
-               last_block_end = docid;
+               num_docids += 128;
        }
+}
+
+void PostingListBuilder::add_first_docid(uint32_t docid)
+{
+       write_header(docid);
        ++num_docids;
+       last_docid = docid;
 }
 
 void PostingListBuilder::finish()
@@ -95,7 +87,10 @@ void PostingListBuilder::finish()
        // No interleaving for partial blocks.
        unsigned char buf[P4NENC_BOUND(128)];
        unsigned char *end = encode_pfor_single_block<128>(pending_deltas.data(), pending_deltas.size(), /*interleaved=*/false, buf);
-       encoded.append(reinterpret_cast<char *>(buf), reinterpret_cast<char *>(end));
+       encoded.insert(encoded.end(), buf, end);
+
+       num_docids += pending_deltas.size();
+       pending_deltas.clear();
 }
 
 void PostingListBuilder::append_block()
@@ -103,14 +98,14 @@ void PostingListBuilder::append_block()
        unsigned char buf[P4NENC_BOUND(128)];
        assert(pending_deltas.size() == 128);
        unsigned char *end = encode_pfor_single_block<128>(pending_deltas.data(), 128, /*interleaved=*/true, buf);
-       encoded.append(reinterpret_cast<char *>(buf), reinterpret_cast<char *>(end));
+       encoded.insert(encoded.end(), buf, end);
 }
 
 void PostingListBuilder::write_header(uint32_t docid)
 {
        unsigned char buf[P4NENC_BOUND(1)];
        unsigned char *end = write_baseval(docid, buf);
-       encoded.append(reinterpret_cast<char *>(buf), end - buf);
+       encoded.insert(encoded.end(), buf, end);
 }
 
 void DictionaryBuilder::add_file(string filename, dir_time)
@@ -163,7 +158,7 @@ string DictionaryBuilder::train(size_t buf_size)
        string buf;
        buf.resize(buf_size);
        size_t ret = ZDICT_trainFromBuffer(&buf[0], buf_size, dictionary_buf.data(), lengths.data(), lengths.size());
-       if (ret == size_t(-1)) {
+       if (ZDICT_isError(ret)) {
                return "";
        }
        dprintf("Sampled %zu bytes in %zu blocks, built a dictionary of size %zu\n", dictionary_buf.size(), lengths.size(), ret);
@@ -175,8 +170,59 @@ string DictionaryBuilder::train(size_t buf_size)
        return buf;
 }
 
-Corpus::Corpus(FILE *outfp, size_t block_size, ZSTD_CDict *cdict, bool store_dir_times)
-       : invindex(new PostingListBuilder *[NUM_TRIGRAMS]), outfp(outfp), block_size(block_size), store_dir_times(store_dir_times), cdict(cdict)
+class EncodingCorpus : public DatabaseReceiver {
+public:
+       EncodingCorpus(FILE *outfp, size_t block_size, ZSTD_CDict *cdict, bool store_dir_times);
+       ~EncodingCorpus();
+
+       void add_file(std::string filename, dir_time dt) override;
+       void flush_block() override;
+       void finish() override;
+
+       std::vector<uint64_t> filename_blocks;
+       size_t num_files = 0, num_files_in_block = 0, num_blocks = 0;
+       bool seen_trigram(uint32_t trgm)
+       {
+               return invindex[trgm] != nullptr;
+       }
+       size_t num_files_seen() const override { return num_files; }
+       PostingListBuilder &get_pl_builder(uint32_t trgm)
+       {
+               return *invindex[trgm];
+       }
+
+       void add_docid(uint32_t trgm, uint32_t docid)
+       {
+               if (invindex[trgm] == nullptr) {
+                       invindex[trgm] = new PostingListBuilder;
+                       invindex[trgm]->add_first_docid(docid);
+               } else {
+                       invindex[trgm]->add_docid(docid);
+               }
+       }
+
+       size_t num_trigrams() const;
+       std::string get_compressed_dir_times();
+
+private:
+       void compress_dir_times(size_t allowed_slop);
+
+       std::unique_ptr<PostingListBuilder *[]> invindex;
+       FILE *outfp;
+       off_t outfp_pos;  // Cheaper than calling ftell(outfp) all the time.
+       std::string current_block;
+       std::string tempbuf;
+       const size_t block_size;
+       const bool store_dir_times;
+       ZSTD_CDict *cdict;
+
+       ZSTD_CStream *dir_time_ctx = nullptr;
+       std::string dir_times;  // Buffer of still-uncompressed data.
+       std::string dir_times_compressed;
+};
+
+EncodingCorpus::EncodingCorpus(FILE *outfp, size_t block_size, ZSTD_CDict *cdict, bool store_dir_times)
+       : invindex(new PostingListBuilder *[NUM_TRIGRAMS]), outfp(outfp), outfp_pos(ftell(outfp)), block_size(block_size), store_dir_times(store_dir_times), cdict(cdict)
 {
        fill(invindex.get(), invindex.get() + NUM_TRIGRAMS, nullptr);
        if (store_dir_times) {
@@ -185,22 +231,14 @@ Corpus::Corpus(FILE *outfp, size_t block_size, ZSTD_CDict *cdict, bool store_dir
        }
 }
 
-Corpus::~Corpus()
+EncodingCorpus::~EncodingCorpus()
 {
        for (unsigned i = 0; i < NUM_TRIGRAMS; ++i) {
                delete invindex[i];
        }
 }
 
-PostingListBuilder &Corpus::get_pl_builder(uint32_t trgm)
-{
-       if (invindex[trgm] == nullptr) {
-               invindex[trgm] = new PostingListBuilder;
-       }
-       return *invindex[trgm];
-}
-
-void Corpus::add_file(string filename, dir_time dt)
+void EncodingCorpus::add_file(string filename, dir_time dt)
 {
        ++num_files;
        if (!current_block.empty()) {
@@ -224,7 +262,7 @@ void Corpus::add_file(string filename, dir_time dt)
        }
 }
 
-void Corpus::compress_dir_times(size_t allowed_slop)
+void EncodingCorpus::compress_dir_times(size_t allowed_slop)
 {
        while (dir_times.size() >= allowed_slop) {
                size_t old_size = dir_times_compressed.size();
@@ -256,7 +294,7 @@ void Corpus::compress_dir_times(size_t allowed_slop)
        }
 }
 
-void Corpus::flush_block()
+void EncodingCorpus::flush_block()
 {
        if (current_block.empty()) {
                return;
@@ -266,36 +304,58 @@ void Corpus::flush_block()
 
        // Create trigrams.
        const char *ptr = current_block.c_str();
-       while (ptr < current_block.c_str() + current_block.size()) {
-               string_view s(ptr);
-               if (s.size() >= 3) {
-                       for (size_t j = 0; j < s.size() - 2; ++j) {
-                               uint32_t trgm = read_trigram(s, j);
-                               get_pl_builder(trgm).add_docid(docid);
+       const char *end = ptr + current_block.size();
+       while (ptr < end - 3) {  // Must be at least one filename left, that's at least three bytes.
+               if (ptr[0] == '\0') {
+                       // This filename is zero bytes, so skip it (and the zero terminator).
+                       ++ptr;
+                       continue;
+               } else if (ptr[1] == '\0') {
+                       // This filename is one byte, so skip it (and the zero terminator).
+                       ptr += 2;
+                       continue;
+               } else if (ptr[2] == '\0') {
+                       // This filename is two bytes, so skip it (and the zero terminator).
+                       ptr += 3;
+                       continue;
+               }
+               for (;;) {
+                       // NOTE: Will read one byte past the end of the trigram, but it's OK,
+                       // since we always call it from contexts where there's a terminating zero byte.
+                       uint32_t trgm;
+                       memcpy(&trgm, ptr, sizeof(trgm));
+                       ++ptr;
+                       trgm = le32toh(trgm);
+                       add_docid(trgm & 0xffffff, docid);
+                       if (trgm <= 0xffffff) {
+                               // Terminating zero byte, so we're done with this filename.
+                               // Skip the remaining two bytes, and the zero terminator.
+                               ptr += 3;
+                               break;
                        }
                }
-               ptr += s.size() + 1;
        }
 
        // Compress and add the filename block.
-       filename_blocks.push_back(ftell(outfp));
+       filename_blocks.push_back(outfp_pos);
        string compressed = zstd_compress(current_block, cdict, &tempbuf);
        if (fwrite(compressed.data(), compressed.size(), 1, outfp) != 1) {
                perror("fwrite()");
                exit(1);
        }
+       outfp_pos += compressed.size();
 
        current_block.clear();
        num_files_in_block = 0;
        ++num_blocks;
 }
 
-void Corpus::finish()
+void EncodingCorpus::finish()
 {
        flush_block();
 }
 
-size_t Corpus::num_trigrams() const
+size_t EncodingCorpus::num_trigrams() const
 {
        size_t num = 0;
        for (unsigned trgm = 0; trgm < NUM_TRIGRAMS; ++trgm) {
@@ -306,7 +366,7 @@ size_t Corpus::num_trigrams() const
        return num;
 }
 
-string Corpus::get_compressed_dir_times()
+string EncodingCorpus::get_compressed_dir_times()
 {
        if (!store_dir_times) {
                return "";
@@ -385,7 +445,7 @@ uint32_t next_prime(uint32_t x)
        return x;
 }
 
-unique_ptr<Trigram[]> create_hashtable(Corpus &corpus, const vector<uint32_t> &all_trigrams, uint32_t ht_size, uint32_t num_overflow_slots)
+unique_ptr<Trigram[]> create_hashtable(EncodingCorpus &corpus, const vector<uint32_t> &all_trigrams, uint32_t ht_size, uint32_t num_overflow_slots)
 {
        unique_ptr<Trigram[]> ht(new Trigram[ht_size + num_overflow_slots + 1]);  // 1 for the sentinel element at the end.
        for (unsigned i = 0; i < ht_size + num_overflow_slots + 1; ++i) {
@@ -395,7 +455,7 @@ unique_ptr<Trigram[]> create_hashtable(Corpus &corpus, const vector<uint32_t> &a
        }
        for (uint32_t trgm : all_trigrams) {
                // We don't know offset yet, so set it to zero.
-               Trigram to_insert{ trgm, uint32_t(corpus.get_pl_builder(trgm).num_docids), 0 };
+               Trigram to_insert{ trgm, uint32_t(corpus.get_pl_builder(trgm).get_num_docids()), 0 };
 
                uint32_t bucket = hash_trigram(trgm, ht_size);
                unsigned distance = 0;
@@ -427,11 +487,26 @@ DatabaseBuilder::DatabaseBuilder(const char *outfile, gid_t owner, int block_siz
        if (path.empty()) {
                path = ".";
        }
-       int fd = open(path.c_str(), O_WRONLY | O_TMPFILE, 0640);
-       if (fd == -1) {
+       int fd = -1;
+#ifdef O_TMPFILE
+       fd = open(path.c_str(), O_WRONLY | O_TMPFILE, 0640);
+       if (fd == -1 && errno != EOPNOTSUPP && errno != EISDIR) {
                perror(path.c_str());
                exit(1);
        }
+#endif
+       if (fd == -1) {
+               temp_filename = string(outfile) + ".XXXXXX";
+               fd = mkstemp(&temp_filename[0]);
+               if (fd == -1) {
+                       perror(temp_filename.c_str());
+                       exit(1);
+               }
+               if (fchmod(fd, 0640) == -1) {
+                       perror("fchmod");
+                       exit(1);
+               }
+       }
 
        if (owner != (gid_t)-1) {
                if (fchown(fd, (uid_t)-1, owner) == -1) {
@@ -477,10 +552,10 @@ DatabaseBuilder::DatabaseBuilder(const char *outfile, gid_t owner, int block_siz
        hdr.conf_block_offset_bytes = 0;
 }
 
-Corpus *DatabaseBuilder::start_corpus(bool store_dir_times)
+DatabaseReceiver *DatabaseBuilder::start_corpus(bool store_dir_times)
 {
        corpus_start = steady_clock::now();
-       corpus = new Corpus(outfp, block_size, cdict, store_dir_times);
+       corpus = new EncodingCorpus(outfp, block_size, cdict, store_dir_times);
        return corpus;
 }
 
@@ -518,8 +593,8 @@ void DatabaseBuilder::finish_corpus()
                        continue;
                PostingListBuilder &pl_builder = corpus->get_pl_builder(trgm);
                pl_builder.finish();
-               longest_posting_list = max(longest_posting_list, pl_builder.num_docids);
-               trigrams += pl_builder.num_docids;
+               longest_posting_list = max(longest_posting_list, pl_builder.get_num_docids());
+               trigrams += pl_builder.get_num_docids();
                bytes_for_posting_lists += pl_builder.encoded.size();
        }
        size_t num_trigrams = corpus->num_trigrams();
@@ -560,7 +635,7 @@ void DatabaseBuilder::finish_corpus()
                        continue;
                }
 
-               const string &encoded = corpus->get_pl_builder(hashtable[i].trgm).encoded;
+               const vector<unsigned char> &encoded = corpus->get_pl_builder(hashtable[i].trgm).encoded;
                offset += encoded.size();
        }
 
@@ -574,7 +649,7 @@ void DatabaseBuilder::finish_corpus()
                if (hashtable[i].num_docids == 0) {
                        continue;
                }
-               const string &encoded = corpus->get_pl_builder(hashtable[i].trgm).encoded;
+               const vector<unsigned char> &encoded = corpus->get_pl_builder(hashtable[i].trgm).encoded;
                fwrite(encoded.data(), encoded.size(), 1, outfp);
        }
 
@@ -608,14 +683,27 @@ void DatabaseBuilder::finish_corpus()
        fseek(outfp, 0, SEEK_SET);
        fwrite(&hdr, sizeof(hdr), 1, outfp);
 
-       // Give the file a proper name, making it visible in the file system.
-       // TODO: It would be nice to be able to do this atomically, like with rename.
-       unlink(outfile.c_str());
-       char procpath[256];
-       snprintf(procpath, sizeof(procpath), "/proc/self/fd/%d", fileno(outfp));
-       if (linkat(AT_FDCWD, procpath, AT_FDCWD, outfile.c_str(), AT_SYMLINK_FOLLOW) == -1) {
-               perror("linkat");
-               exit(1);
+       // This is needed on systems that simulate linkat() by copying
+       // the contents of the file instead of linking.
+       fflush(outfp);
+
+       if (!temp_filename.empty()) {
+               if (rename(temp_filename.c_str(), outfile.c_str()) == -1) {
+                       perror("rename");
+                       exit(1);
+               }
+       } else {
+#ifdef O_TMPFILE
+               // Give the file a proper name, making it visible in the file system.
+               // TODO: It would be nice to be able to do this atomically, like with rename.
+               unlink(outfile.c_str());
+               char procpath[256];
+               snprintf(procpath, sizeof(procpath), "/proc/self/fd/%d", fileno(outfp));
+               if (linkat(AT_FDCWD, procpath, AT_FDCWD, outfile.c_str(), AT_SYMLINK_FOLLOW) == -1) {
+                       perror("linkat");
+                       exit(1);
+               }
+#endif
        }
 
        fclose(outfp);