Drop dependence on libtar.

[cumulus.git] / store.h

diff --git a/store.h b/store.h
index 1ef5db4..75c2008 100644 (file)
--- a/store.h
+++ b/store.h
@@ -3,14 +3,12 @@
  *
  * 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>
@@ -41,6 +39,30 @@ public:
     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
  * may only be written out all at once, since the tar header must be written
  * first; incremental writing is not supported. */
@@ -49,10 +71,11 @@ public:
     Tarfile(const std::string &path, 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() { return size; }
+    size_t size_estimate();
 
     void internal_write_object(const std::string &path,
                                const char *data, size_t len);
@@ -60,7 +83,13 @@ public:
 private:
     size_t size;
     std::string segment_name;
-    TAR *t;
+
+    /* 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 {
@@ -79,6 +108,9 @@ public:
     // Ensure all segments have been fully written.
     void sync();
 
+    // Dump statistics to stdout about how much data has been written
+    void dump_stats();
+
 private:
     struct segment_info {
         Tarfile *file;
@@ -139,4 +171,11 @@ private:
     ObjectReference ref;
 };
 
+/* Program through which segment data is piped before being written to file. */
+extern const char *filter_program;
+
+/* Extension which should be appended to segments written out (.tar is already
+ * included; this adds to it) */
+extern const char *filter_extension;
+
 #endif // _LBS_STORE_H