The map::at method does not always exist, so instead use map::find.

[cumulus.git] / store.h

diff --git a/store.h b/store.h
index 1fd366b..aa98e30 100644 (file)
--- a/store.h
+++ b/store.h
@@ -1,16 +1,31 @@
-/* LBS: An LFS-inspired filesystem backup system
- * Copyright (C) 2006  Michael Vrable
+/* Cumulus: Smart Filesystem Backup to Dumb Servers
  *
- * Backup data is stored in a collection of objects, which are grouped together
+ * Copyright (C) 2006-2008  The Regents of the University of California
+ * Written by Michael Vrable <mvrable@cs.ucsd.edu>
+ *
+ * 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
- * is built on top of libtar, and represents segments as TAR files and objects
- * as files within them. */
+ * represents segments as TAR files and objects as files within them. */
 
 #ifndef _LBS_STORE_H
 #define _LBS_STORE_H
 
 #include <stdint.h>
-#include <libtar.h>
 
 #include <list>
 #include <map>
@@ -19,6 +34,8 @@
 #include <iostream>
 #include <sstream>
 
+#include "localdb.h"
+#include "remote.h"
 #include "sha1.h"
 #include "ref.h"
 
@@ -28,17 +45,28 @@ class LbsObject;
  * metadata.  Currently implemented as map<string, string>. */
 typedef std::map<std::string, std::string> 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;
+
+struct tar_header
+{
+    char name[100];
+    char mode[8];
+    char uid[8];
+    char gid[8];
+    char size[12];
+    char mtime[12];
+    char chksum[8];
+    char typeflag;
+    char linkname[100];
+    char magic[8];
+    char uname[32];
+    char gname[32];
+    char devmajor[8];
+    char devminor[8];
+    char prefix[155];
+    char padding[12];
 };
 
 /* A simple wrapper around a single TAR file to represent a segment.  Objects
@@ -46,32 +74,34 @@ public:
  * 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;
-    TAR *t;
+
+    RemoteFile *file;
 
     /* Filter support. */
     int real_fd, filter_fd;
     pid_t filter_pid;
+
+    // Write data to the tar file
+    void tar_write(const char *data, size_t size);
 };
 
 class TarSegmentStore {
 public:
     // New segments will be stored in the given directory.
-    TarSegmentStore(const std::string &path) { this->path = path; }
+    TarSegmentStore(RemoteStore *remote,
+                    LocalDb *db = NULL)
+        { this->remote = remote; this->db = db; }
     ~TarSegmentStore() { sync(); }
 
     // Writes an object to segment in the store, and returns the name
@@ -90,12 +120,17 @@ public:
 private:
     struct segment_info {
         Tarfile *file;
+        std::string group;
         std::string name;           // UUID
         int count;                  // Objects written to this segment
+        int size;                   // Combined size of objects written
+        std::string basename;       // Name of segment without directory
+        RemoteFile *rf;
     };
 
-    std::string path;
+    RemoteStore *remote;
     std::map<std::string, struct segment_info *> segments;
+    LocalDb *db;
 
     // Ensure that all segments in the given group have been fully written.
     void close_segment(const std::string &group);
@@ -154,4 +189,12 @@ 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