A number of bugfixes:

- Added DB::CompactRange() method.

  Changed manual compaction code so it breaks up compactions of
  big ranges into smaller compactions.

  Changed the code that pushes the output of memtable compactions
  to higher levels to obey the grandparent constraint: i.e., we
  must never have a single file in level L that overlaps too
  much data in level L+1 (to avoid very expensive L-1 compactions).

  Added code to pretty-print internal keys.

- Fixed bug where we would not detect overlap with files in
  level-0 because we were incorrectly using binary search
  on an array of files with overlapping ranges.

  Added "leveldb.sstables" property that can be used to dump
  all of the sstables and ranges that make up the db state.

- Removing post_write_snapshot support.  Email to leveldb mailing
  list brought up no users, just confusion from one person about
  what it meant.

- Fixing static_cast char to unsigned on BIG_ENDIAN platforms.

  Fixes	Issue 35 and Issue 36.

- Comment clarification to address leveldb Issue 37.

- Change license in posix_logger.h to match other files.

- A build problem where uint32 was used instead of uint32_t.

Sync with upstream @24408625

db/db_impl.h

@@ -38,14 +38,12 @@ class DBImpl : public DB {
   virtual void ReleaseSnapshot(const Snapshot* snapshot);
   virtual bool GetProperty(const Slice& property, std::string* value);
   virtual void GetApproximateSizes(const Range* range, int n, uint64_t* sizes);
+  virtual void CompactRange(const Slice* begin, const Slice* end);
 
   // Extra methods (for testing) that are not in the public DB interface
 
-  // Compact any files in the named level that overlap [begin,end]
-  void TEST_CompactRange(
-      int level,
-      const std::string& begin,
-      const std::string& end);
+  // Compact any files in the named level that overlap [*begin,*end]
+  void TEST_CompactRange(int level, const Slice* begin, const Slice* end);
 
   // Force current memtable contents to be compacted.
   Status TEST_CompactMemTable();
@@ -145,8 +143,10 @@ class DBImpl : public DB {
   // Information for a manual compaction
   struct ManualCompaction {
     int level;
-    std::string begin;
-    std::string end;
+    bool done;
+    const InternalKey* begin;   // NULL means beginning of key range
+    const InternalKey* end;     // NULL means end of key range
+    InternalKey tmp_storage;    // Used to keep track of compaction progress
   };
   ManualCompaction* manual_compaction_;