diff options
Diffstat (limited to 'sca-cpp/trunk/components/nosqldb/tinycdb.hpp')
| -rw-r--r-- | sca-cpp/trunk/components/nosqldb/tinycdb.hpp | 133 |
1 files changed, 94 insertions, 39 deletions
diff --git a/sca-cpp/trunk/components/nosqldb/tinycdb.hpp b/sca-cpp/trunk/components/nosqldb/tinycdb.hpp index c2d1f2c50f..b98d622e25 100644 --- a/sca-cpp/trunk/components/nosqldb/tinycdb.hpp +++ b/sca-cpp/trunk/components/nosqldb/tinycdb.hpp @@ -23,6 +23,8 @@ #define tuscany_tinycdb_hpp #include <fcntl.h> +#include <unistd.h> +#include <sys/stat.h> #include <cdb.h> #include "string.hpp" @@ -92,16 +94,16 @@ const bool free(const buffer&b) { */ class TinyCDB { public: - TinyCDB() : owner(false) { + TinyCDB() : owner(false), fd(-1) { + st.st_ino = 0; } - TinyCDB(const string& file) : owner(true), file(file) { - fd = open(c_str(file), O_RDONLY); + TinyCDB(const string& name) : owner(true), name(name), fd(-1) { + st.st_ino = 0; } - TinyCDB(const TinyCDB& c) : owner(false) { - file = c.file; - fd = c.fd; + TinyCDB(const TinyCDB& c) : owner(false), name(c.name), fd(c.fd) { + st.st_ino = c.st.st_ino; } ~TinyCDB() { @@ -114,43 +116,90 @@ public: private: bool owner; - string file; + string name; int fd; - - friend const failable<bool> post(const value& key, const value& val, TinyCDB& cdb); - friend const failable<bool> put(const value& key, const value& val, const TinyCDB& cdb); - friend const failable<value> get(const value& key, const TinyCDB& cdb); - friend const failable<bool> del(const value& key, const TinyCDB& cdb); - friend const failable<bool> rewrite(const lambda<failable<bool>(buffer& buf, const unsigned int klen, const unsigned int vlen)>& update, const lambda<failable<bool>(struct cdb_make&)>& finish, TinyCDB& cdb); - friend const failable<bool> rewrite(const lambda<failable<bool>(buffer& buf, const unsigned int klen, const unsigned int vlen)>& update, const lambda<failable<bool>(struct cdb_make&)>& finish, buffer& buf, const int fd, TinyCDB& cdb); + struct stat st; + + //friend const failable<bool> post(const value& key, const value& val, TinyCDB& cdb); + //friend const failable<bool> put(const value& key, const value& val, TinyCDB& cdb); + //friend const failable<value> get(const value& key, const TinyCDB& cdb); + //friend const failable<bool> del(const value& key, TinyCDB& cdb); + //friend const failable<bool> rewrite(const lambda<failable<bool>(buffer& buf, const unsigned int klen, const unsigned int vlen)>& update, const lambda<failable<bool>(struct cdb_make&)>& finish, TinyCDB& cdb); + //friend const failable<bool> rewrite(const lambda<failable<bool>(buffer& buf, const unsigned int klen, const unsigned int vlen)>& update, const lambda<failable<bool>(struct cdb_make&)>& finish, buffer& buf, const int fd, TinyCDB& cdb); + + friend const string dbname(const TinyCDB& cdb); + friend const failable<int> cdbopen(TinyCDB& cdb); + friend const failable<bool> cdbclose(TinyCDB& cdb); }; /** + * Return the name of the database. + */ +const string dbname(const TinyCDB& cdb) { + return cdb.name; +} + +/** + * Open a database. + */ +const failable<int> cdbopen(TinyCDB& cdb) { + struct stat st; + int s = stat(c_str(cdb.name), &st); + if (s == -1) + return mkfailure<int>(string("Couldn't read database stat ") + cdb.name); + if (st.st_ino != cdb.st.st_ino || cdb.fd == -1) { + if (cdb.fd != -1) + close(cdb.fd); + cdb.fd = open(c_str(cdb.name), O_RDONLY); + if (cdb.fd == -1) + return mkfailure<int>(string("Couldn't open database file ") + cdb.name); + debug(cdb.fd, "tinycdb::open::fd"); + cdb.st = st; + } + return cdb.fd; +} + +/** + * Close a database. + */ +const failable<bool> cdbclose(TinyCDB& cdb) { + close(cdb.fd); + cdb.fd = -1; + return true; +} + +/** * Rewrite a database. The given update function is passed each entry, and * can return true to let the entry added to the new db, false to skip the * entry, or a failure. */ -const failable<bool> rewrite(const lambda<failable<bool>(buffer& buf, const unsigned int klen, const unsigned int vlen)>& update, const lambda<failable<bool>(struct cdb_make&)>& finish, buffer& buf, const int fd, TinyCDB& cdb) { +const failable<bool> rewrite(const lambda<failable<bool>(buffer& buf, const unsigned int klen, const unsigned int vlen)>& update, const lambda<failable<bool>(struct cdb_make&)>& finish, buffer& buf, const int tmpfd, TinyCDB& cdb) { // Initialize new db structure struct cdb_make cdbm; - cdb_make_start(&cdbm, fd); + cdb_make_start(&cdbm, tmpfd); + + // Open existing db + failable<int> ffd = cdbopen(cdb); + if (!hasContent(ffd)) + return mkfailure<bool>(reason(ffd)); + const int fd = content(ffd); // Read the db header unsigned int pos = 0; - if (lseek(cdb.fd, 0, SEEK_SET) != 0) + if (lseek(fd, 0, SEEK_SET) != 0) return mkfailure<bool>("Could not seek to database start"); - if (::read(cdb.fd, buf, 2048) != 2048) + if (::read(fd, buf, 2048) != 2048) return mkfailure<bool>("Could not read database header"); pos += 2048; unsigned int eod = cdb_unpack(buf); - debug(pos, "tinycdb::post::eod"); + debug(pos, "tinycdb::rewrite::eod"); // Read and add the existing entries while(pos < eod) { if (eod - pos < 8) return mkfailure<bool>("Invalid database format, couldn't read entry header"); - if (::read(cdb.fd, buf, 8) != 8) + if (::read(fd, buf, 8) != 8) return mkfailure<bool>("Couldn't read entry header"); pos += 8; unsigned int klen = cdb_unpack(buf); @@ -161,13 +210,13 @@ const failable<bool> rewrite(const lambda<failable<bool>(buffer& buf, const unsi buf = mkbuffer(buf, elen); if (eod - pos < elen) return mkfailure<bool>("Invalid database format, couldn't read entry"); - if ((unsigned int)::read(cdb.fd, buf, elen) != elen) + if ((unsigned int)::read(fd, buf, elen) != elen) return mkfailure<bool>("Couldn't read entry"); pos += elen; // Apply the update function to the entry - debug(string((char*)buf, klen), "tinycdb::post::existing key"); - debug(string(((char*)buf) + klen, vlen), "tinycdb::post::existing value"); + debug(string((char*)buf, klen), "tinycdb::rewrite::existing key"); + debug(string(((char*)buf) + klen, vlen), "tinycdb::rewrite::existing value"); const failable<bool> u = update(buf, klen, vlen); if (!hasContent(u)) return u; @@ -196,30 +245,29 @@ const failable<bool> rewrite(const lambda<failable<bool>(buffer& buf, const unsi } const failable<bool> rewrite(const lambda<failable<bool>(buffer& buf, const unsigned int klen, const unsigned int vlen)>& update, const lambda<failable<bool>(struct cdb_make&)>& finish, TinyCDB& cdb) { - if (cdb.fd == -1) - return mkfailure<bool>("Could not open database"); // Create a new temporary db file - const char* tmpfile = c_str(cdb.file + ".tmp"); - unlink(tmpfile); - int fd = open(tmpfile, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW, 0666); - if (fd == -1) + string tmpname = dbname(cdb) + ".XXXXXX"; + int tmpfd = mkstemp(const_cast<char*>(c_str(tmpname))); + if (tmpfd == -1) return mkfailure<bool>("Could not create temporary database"); // Rewrite the db, apply the update function to each entry buffer buf = mkbuffer(2048); - const failable<bool> r = rewrite(update, finish, buf, fd, cdb); + const failable<bool> r = rewrite(update, finish, buf, tmpfd, cdb); if (!hasContent(r)) { - close(fd); + close(tmpfd); free(buf); return r; } // Atomically replace the db and reopen it in read mode - if (rename(tmpfile, c_str(cdb.file)) == -1) + if (rename(c_str(tmpname), c_str(dbname(cdb))) == -1) return mkfailure<bool>("Could not rename temporary database"); - close(cdb.fd); - cdb.fd = open(c_str(cdb.file), O_RDONLY); + cdbclose(cdb); + failable<int> ffd = cdbopen(cdb); + if (!hasContent(ffd)) + return mkfailure<bool>(reason(ffd)); return true; } @@ -230,6 +278,7 @@ const failable<bool> rewrite(const lambda<failable<bool>(buffer& buf, const unsi const failable<bool> post(const value& key, const value& val, TinyCDB& cdb) { debug(key, "tinycdb::post::key"); debug(val, "tinycdb::post::value"); + debug(dbname(cdb), "tinycdb::post::dbname"); const string ks(scheme::writeValue(key)); const string vs(scheme::writeValue(val)); @@ -260,6 +309,7 @@ const failable<bool> post(const value& key, const value& val, TinyCDB& cdb) { const failable<bool> put(const value& key, const value& val, TinyCDB& cdb) { debug(key, "tinycdb::put::key"); debug(val, "tinycdb::put::value"); + debug(dbname(cdb), "tinycdb::put::dbname"); const string ks(scheme::writeValue(key)); const string vs(scheme::writeValue(val)); @@ -287,18 +337,22 @@ const failable<bool> put(const value& key, const value& val, TinyCDB& cdb) { /** * Get an item from the database. */ -const failable<value> get(const value& key, const TinyCDB& cdb) { +const failable<value> get(const value& key, TinyCDB& cdb) { debug(key, "tinycdb::get::key"); - if (cdb.fd == -1) - return mkfailure<value>("Could not open database"); + debug(dbname(cdb), "tinycdb::get::dbname"); + + const failable<int> ffd = cdbopen(cdb); + if (!hasContent(ffd)) + return mkfailure<value>(reason(ffd)); + const int fd = content(ffd); const string ks(scheme::writeValue(key)); cdbi_t vlen; - if (cdb_seek(cdb.fd, c_str(ks), length(ks), &vlen) <= 0) + if (cdb_seek(fd, c_str(ks), length(ks), &vlen) <= 0) return mkfailure<value>("Could not get entry"); char* data = gc_cnew(vlen + 1); - cdb_bread(cdb.fd, data, vlen); + cdb_bread(fd, data, vlen); data[vlen] = '\0'; const value val(scheme::readValue(string(data))); @@ -311,6 +365,7 @@ const failable<value> get(const value& key, const TinyCDB& cdb) { */ const failable<bool> del(const value& key, TinyCDB& cdb) { debug(key, "tinycdb::delete::key"); + debug(dbname(cdb), "tinycdb::delete::dbname"); const string ks(scheme::writeValue(key)); |