A number of fixes:

- Replace raw slice comparison with a call to user comparator.
  Added test for custom comparators.

- Fix end of namespace comments.

- Fixed bug in picking inputs for a level-0 compaction.

  When finding overlapping files, the covered range may expand
  as files are added to the input set.  We now correctly expand
  the range when this happens instead of continuing to use the
  old range.  For example, suppose L0 contains files with the
  following ranges:

      F1: a .. d
      F2:    c .. g
      F3:       f .. j

  and the initial compaction target is F3.  We used to search
  for range f..j which yielded {F2,F3}.  However we now expand
  the range as soon as another file is added.  In this case,
  when F2 is added, we expand the range to c..j and restart the
  search.  That picks up file F1 as well.

  This change fixes a bug related to deleted keys showing up
  incorrectly after a compaction as described in Issue 44.

(Sync with upstream @25072954)

util/arena.cc

@@ -65,4 +65,4 @@ char* Arena::AllocateNewBlock(size_t block_bytes) {
   return result;
 }
 
-}
+}  // namespace leveldb

util/arena.h

@@ -63,6 +63,6 @@ inline char* Arena::Allocate(size_t bytes) {
   return AllocateFallback(bytes);
 }
 
-}
+}  // namespace leveldb
 
 #endif  // STORAGE_LEVELDB_UTIL_ARENA_H_

util/arena_test.cc

@@ -61,7 +61,7 @@ TEST(ArenaTest, Simple) {
   }
 }
 
-}
+}  // namespace leveldb
 
 int main(int argc, char** argv) {
   return leveldb::test::RunAllTests();

util/cache.cc

@@ -325,4 +325,4 @@ Cache* NewLRUCache(size_t capacity) {
   return new ShardedLRUCache(capacity);
 }
 
-}
+}  // namespace leveldb

util/cache_test.cc

@@ -179,7 +179,7 @@ TEST(CacheTest, NewId) {
   ASSERT_NE(a, b);
 }
 
-}
+}  // namespace leveldb
 
 int main(int argc, char** argv) {
   return leveldb::test::RunAllTests();

util/coding.cc

@@ -191,4 +191,4 @@ bool GetLengthPrefixedSlice(Slice* input, Slice* result) {
   }
 }
 
-}
+}  // namespace leveldb

util/coding.h

@@ -99,6 +99,6 @@ inline const char* GetVarint32Ptr(const char* p,
   return GetVarint32PtrFallback(p, limit, value);
 }
 
-}
+}  // namespace leveldb
 
 #endif  // STORAGE_LEVELDB_UTIL_CODING_H_

util/coding_test.cc

@@ -166,7 +166,7 @@ TEST(Coding, Strings) {
   ASSERT_EQ("", input.ToString());
 }
 
-}
+}  // namespace leveldb
 
 int main(int argc, char** argv) {
   return leveldb::test::RunAllTests();

util/comparator.cc

@@ -63,11 +63,11 @@ class BytewiseComparatorImpl : public Comparator {
     // *key is a run of 0xffs.  Leave it alone.
   }
 };
-}
+}  // namespace
 static const BytewiseComparatorImpl bytewise;
 
 const Comparator* BytewiseComparator() {
   return &bytewise;
 }
 
-}
+}  // namespace leveldb

util/crc32c.cc

@@ -328,5 +328,5 @@ uint32_t Extend(uint32_t crc, const char* buf, size_t size) {
   return l ^ 0xffffffffu;
 }
 
-}
-}
+}  // namespace crc32c
+}  // namespace leveldb

util/crc32c.h

@@ -39,7 +39,7 @@ inline uint32_t Unmask(uint32_t masked_crc) {
   return ((rot >> 17) | (rot << 15));
 }
 
-}
-}
+}  // namespace crc32c
+}  // namespace leveldb
 
 #endif  // STORAGE_LEVELDB_UTIL_CRC32C_H_

util/crc32c_test.cc

@@ -64,8 +64,8 @@ TEST(CRC, Mask) {
   ASSERT_EQ(crc, Unmask(Unmask(Mask(Mask(crc)))));
 }
 
-}
-}
+}  // namespace crc32c
+}  // namespace leveldb
 
 int main(int argc, char** argv) {
   return leveldb::test::RunAllTests();

util/env.cc

@@ -79,4 +79,4 @@ Status ReadFileToString(Env* env, const std::string& fname, std::string* data) {
 EnvWrapper::~EnvWrapper() {
 }
 
-}
+}  // namespace leveldb

util/env_posix.cc

@@ -553,7 +553,7 @@ void PosixEnv::StartThread(void (*function)(void* arg), void* arg) {
               pthread_create(&t, NULL,  &StartThreadWrapper, state));
 }
 
-}
+}  // namespace
 
 static pthread_once_t once = PTHREAD_ONCE_INIT;
 static Env* default_env;
@@ -564,4 +564,4 @@ Env* Env::Default() {
   return default_env;
 }
 
-}
+}  // namespace leveldb

util/env_test.cc

@@ -95,7 +95,7 @@ TEST(EnvPosixTest, StartThread) {
   ASSERT_EQ(state.val, 3);
 }
 
-}
+}  // namespace leveldb
 
 int main(int argc, char** argv) {
   return leveldb::test::RunAllTests();

util/hash.cc

@@ -42,4 +42,4 @@ uint32_t Hash(const char* data, size_t n, uint32_t seed) {
 }
 
 
-}
+}  // namespace leveldb

util/histogram.cc

@@ -136,4 +136,4 @@ std::string Histogram::ToString() const {
   return r;
 }
 
-}
+}  // namespace leveldb

util/histogram.h

@@ -37,6 +37,6 @@ class Histogram {
   double StandardDeviation() const;
 };
 
-}
+}  // namespace leveldb
 
 #endif  // STORAGE_LEVELDB_UTIL_HISTOGRAM_H_

util/logging.cc

@@ -78,4 +78,4 @@ bool ConsumeDecimalNumber(Slice* in, uint64_t* val) {
   return (digits > 0);
 }
 
-}
+}  // namespace leveldb

util/logging.h

@@ -42,6 +42,6 @@ extern bool ConsumeChar(Slice* in, char c);
 // unspecified state.
 extern bool ConsumeDecimalNumber(Slice* in, uint64_t* val);
 
-}
+}  // namespace leveldb
 
 #endif  // STORAGE_LEVELDB_UTIL_LOGGING_H_

util/mutexlock.h

@@ -33,7 +33,7 @@ class MutexLock {
   void operator=(const MutexLock&);
 };
 
-}
+}  // namespace leveldb
 
 
 #endif  // STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_

util/options.cc

@@ -25,4 +25,4 @@ Options::Options()
 }
 
 
-}
+}  // namespace leveldb

util/posix_logger.h

@@ -93,6 +93,6 @@ class PosixLogger : public Logger {
   }
 };
 
-}
+}  // namespace leveldb
 
 #endif  // STORAGE_LEVELDB_UTIL_POSIX_LOGGER_H_

util/random.h

@@ -54,6 +54,6 @@ class Random {
   }
 };
 
-}
+}  // namespace leveldb
 
 #endif  // STORAGE_LEVELDB_UTIL_RANDOM_H_

util/status.cc

@@ -72,4 +72,4 @@ std::string Status::ToString() const {
   }
 }
 
-}
+}  // namespace leveldb

util/testharness.cc

@@ -73,5 +73,5 @@ int RandomSeed() {
   return result;
 }
 
-}
-}
+}  // namespace test
+}  // namespace leveldb

util/testharness.h

@@ -132,7 +132,7 @@ void TCONCAT(_Test_,name)::_Run()
 extern bool RegisterTest(const char* base, const char* name, void (*func)());
 
 
-}
-}
+}  // namespace test
+}  // namespace leveldb
 
 #endif  // STORAGE_LEVELDB_UTIL_TESTHARNESS_H_

util/testutil.cc

@@ -47,5 +47,5 @@ extern Slice CompressibleString(Random* rnd, double compressed_fraction,
   return Slice(*dst);
 }
 
-}
-}
+}  // namespace test
+}  // namespace leveldb

util/testutil.h

@@ -47,7 +47,7 @@ class ErrorEnv : public EnvWrapper {
   }
 };
 
-}
-}
+}  // namespace test
+}  // namespace leveldb
 
 #endif  // STORAGE_LEVELDB_UTIL_TESTUTIL_H_