Merge branch 'master' into columnfamilies

include/rocksdb/db.h

@@ -363,7 +363,15 @@ class DB {
   virtual Status DisableFileDeletions() = 0;
 
   // Allow compactions to delete obselete files.
-  virtual Status EnableFileDeletions() = 0;
+  // If force == true, the call to EnableFileDeletions() will guarantee that
+  // file deletions are enabled after the call, even if DisableFileDeletions()
+  // was called multiple times before.
+  // If force == false, EnableFileDeletions will only enable file deletion
+  // after it's been called at least as many times as DisableFileDeletions(),
+  // enabling the two methods to be called by two threads concurrently without
+  // synchronization -- i.e., file deletions will be enabled only after both
+  // threads call EnableFileDeletions()
+  virtual Status EnableFileDeletions(bool force = true) = 0;
 
   // GetLiveFiles followed by GetSortedWalFiles can generate a lossless backup
 

include/rocksdb/status.h

@@ -25,7 +25,7 @@ namespace rocksdb {
 class Status {
  public:
   // Create a success status.
-  Status() : state_(nullptr) { }
+  Status() : code_(kOk), state_(nullptr) { }
   ~Status() { delete[] state_; }
 
   // Copy the specified status.
@@ -39,6 +39,10 @@ class Status {
   static Status NotFound(const Slice& msg, const Slice& msg2 = Slice()) {
     return Status(kNotFound, msg, msg2);
   }
+  // Fast path for not found without malloc;
+  static Status NotFound() {
+    return Status(kNotFound);
+  }
   static Status Corruption(const Slice& msg, const Slice& msg2 = Slice()) {
     return Status(kCorruption, msg, msg2);
   }
@@ -59,7 +63,7 @@ class Status {
   }
 
   // Returns true iff the status indicates success.
-  bool ok() const { return (state_ == nullptr); }
+  bool ok() const { return code() == kOk; }
 
   // Returns true iff the status indicates a NotFound error.
   bool IsNotFound() const { return code() == kNotFound; }
@@ -87,13 +91,6 @@ class Status {
   std::string ToString() const;
 
  private:
-  // OK status has a nullptr state_.  Otherwise, state_ is a new[] array
-  // of the following form:
-  //    state_[0..3] == length of message
-  //    state_[4]    == code
-  //    state_[5..]  == message
-  const char* state_;
-
   enum Code {
     kOk = 0,
     kNotFound = 1,
@@ -105,20 +102,30 @@ class Status {
     kIncomplete = 7
   };
 
-  Code code() const {
-    return (state_ == nullptr) ? kOk : static_cast<Code>(state_[4]);
-  }
+  // A nullptr state_ (which is always the case for OK) means the message
+  // is empty.
+  // of the following form:
+  //    state_[0..3] == length of message
+  //    state_[4..]  == message
+  Code code_;
+  const char* state_;
 
+  Code code() const {
+    return code_;
+  }
+  explicit Status(Code code) : code_(code), state_(nullptr) { }
   Status(Code code, const Slice& msg, const Slice& msg2);
   static const char* CopyState(const char* s);
 };
 
 inline Status::Status(const Status& s) {
+  code_ = s.code_;
   state_ = (s.state_ == nullptr) ? nullptr : CopyState(s.state_);
 }
 inline void Status::operator=(const Status& s) {
   // The following condition catches both aliasing (when this == &s),
   // and the common case where both s and *this are ok.
+  code_ = s.code_;
   if (state_ != s.state_) {
     delete[] state_;
     state_ = (s.state_ == nullptr) ? nullptr : CopyState(s.state_);

include/rocksdb/transaction_log.h

@@ -56,7 +56,7 @@ class LogFile {
 };
 
 struct BatchResult {
-  SequenceNumber sequence = SequenceNumber();
+  SequenceNumber sequence = 0;
   std::unique_ptr<WriteBatch> writeBatchPtr;
 };
 

include/utilities/stackable_db.h

@@ -158,8 +158,8 @@ class StackableDB : public DB {
     return db_->DisableFileDeletions();
   }
 
-  virtual Status EnableFileDeletions() override {
-    return db_->EnableFileDeletions();
+  virtual Status EnableFileDeletions(bool force) override {
+    return db_->EnableFileDeletions(force);
   }
 
   virtual Status GetLiveFiles(std::vector<std::string>& vec, uint64_t* mfs,