X-Git-Url: http://git.vrable.net/?p=cumulus.git;a=blobdiff_plain;f=store.h;h=016e2756231e4d6b5150d5a4d4f02fae8d9f8a1c;hp=a959cce9107f6666a5953e5a3259f69b182d54df;hb=3d780590edec4583eb3ef0ca16120afd0f7451f9;hpb=a4cf5f4d8df46fa00992a210d587cd824cedcb08 diff --git a/store.h b/store.h index a959cce..016e275 100644 --- a/store.h +++ b/store.h @@ -1,7 +1,23 @@ -/* LBS: An LFS-inspired filesystem backup system - * Copyright (C) 2006 Michael Vrable +/* Cumulus: Efficient Filesystem Backup to the Cloud + * Copyright (C) 2006-2008 The Cumulus Developers + * See the AUTHORS file for a list of contributors. * - * Backup data is stored in a collection of objects, which are grouped together + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +/* Backup data is stored in a collection of objects, which are grouped together * into segments for storage purposes. This implementation of the object store * represents segments as TAR files and objects as files within them. */ @@ -18,8 +34,9 @@ #include #include "localdb.h" -#include "sha1.h" +#include "remote.h" #include "ref.h" +#include "third_party/sha1.h" class LbsObject; @@ -27,19 +44,6 @@ class LbsObject; * metadata. Currently implemented as map. */ typedef std::map dictionary; -/* IOException will be thrown if an error occurs while reading or writing in - * one of the I/O wrappers. Depending upon the context; this may be fatal or - * not--typically, errors reading/writing the store will be serious, but errors - * reading an individual file are less so. */ -class IOException : public std::exception { -private: - std::string error; -public: - explicit IOException(const std::string &err) { error = err; } - virtual ~IOException() throw () { } - std::string getError() const { return error; } -}; - /* Simplified TAR header--we only need to store regular files, don't need to * handle long filenames, etc. */ static const int TAR_BLOCK_SIZE = 512; @@ -69,22 +73,20 @@ struct tar_header * first; incremental writing is not supported. */ class Tarfile { public: - Tarfile(const std::string &path, const std::string &segment); + Tarfile(RemoteFile *file, const std::string &segment); ~Tarfile(); - int spawn_filter(int fd_out); void write_object(int id, const char *data, size_t len); // Return an estimate of the size of the file. size_t size_estimate(); - void internal_write_object(const std::string &path, - const char *data, size_t len); - private: size_t size; std::string segment_name; + RemoteFile *file; + /* Filter support. */ int real_fd, filter_fd; pid_t filter_pid; @@ -96,9 +98,9 @@ private: class TarSegmentStore { public: // New segments will be stored in the given directory. - TarSegmentStore(const std::string &path, + TarSegmentStore(RemoteStore *remote, LocalDb *db = NULL) - { this->path = path; this->db = db; } + { this->remote = remote; this->db = db; } ~TarSegmentStore() { sync(); } // Writes an object to segment in the store, and returns the name @@ -106,7 +108,9 @@ public: // used to control object placement; objects with different group // parameters are kept in separate segments. ObjectReference write_object(const char *data, size_t len, - const std::string &group = ""); + const std::string &group = "", + const std::string &checksum = "", + double age = 0.0); // Ensure all segments have been fully written. void sync(); @@ -117,13 +121,15 @@ public: private: struct segment_info { Tarfile *file; + std::string group; std::string name; // UUID int count; // Objects written to this segment + int data_size; // Combined size of objects written std::string basename; // Name of segment without directory - std::string fullname; // Full path to stored segment + RemoteFile *rf; }; - std::string path; + RemoteStore *remote; std::map segments; LocalDb *db; @@ -151,27 +157,32 @@ public: // Data in an object must be written all at once, and cannot be generated // incrementally. Data can be an arbitrary block of binary data of any // size. The pointer to the data need only remain valid until write() is - // called. - void set_data(const char *d, size_t len) { data = d; data_len = len; } + // called. If checksum is non-NULL then it is assumed to contain a hash + // value for the data; this provides an optimization in case the caller has + // already checksummed the data. Otherwise the set_data will compute a + // hash of the data itself. + void set_data(const char *d, size_t len, const char *checksum); + + // Explicitly sets the age of the data, for later garbage-collection or + // repacking purposes. If not set, the age defaults to the current time. + // The age is stored in the database as a floating point value, expressing + // the time in Julian days. + void set_age(double age) { this->age = age; } // Write an object to a segment, thus making it permanent. This function // can be called at most once. void write(TarSegmentStore *store); - // Compute the checksum of an object, and include it in the object - // reference. This should be called after write(), and the data specified - // by set_data() must remain valid through the call to checksum(). - void checksum(); - // An object is assigned a permanent name once it has been written to a // segment. Until that time, its name cannot be determined. - std::string get_name() const { return ref.to_string(); } ObjectReference get_ref() { return ref; } private: std::string group; + double age; const char *data; size_t data_len; + std::string checksum; bool written; ObjectReference ref; @@ -184,4 +195,12 @@ extern const char *filter_program; * included; this adds to it) */ extern const char *filter_extension; +/* Launch a process to filter data written to a file descriptor. fd_out is the + * file descriptor where the filtered data should be written. program is the + * filter program to execute (a single string which will be interpreted by + * /bin/sh). The return value is a file descriptor to which the data to be + * filtered should be written. The process ID of the filter process is stored + * at address filter_pid if non-NULL. */ +int spawn_filter(int fd_out, const char *program, pid_t *filter_pid); + #endif // _LBS_STORE_H