1 files changed, 18 insertions, 0 deletions
diff --git a/include/leveldb/env.h b/include/leveldb/env.h
index f709514da6..99b6c21414 100644
--- a/include/leveldb/env.h
+++ b/include/leveldb/env.h
@@ -69,6 +69,21 @@ class Env {
   virtual Status NewWritableFile(const std::string& fname,
                                  WritableFile** result) = 0;
 
+  // Create an object that either appends to an existing file, or
+  // writes to a new file (if the file does not exist to begin with).
+  // On success, stores a pointer to the new file in *result and
+  // returns OK.  On failure stores NULL in *result and returns
+  // non-OK.
+  //
+  // The returned file will only be accessed by one thread at a time.
+  //
+  // May return an IsNotSupportedError error if this Env does
+  // not allow appending to an existing file.  Users of Env (including
+  // the leveldb implementation) must be prepared to deal with
+  // an Env that does not support appending.
+  virtual Status NewAppendableFile(const std::string& fname,
+                                   WritableFile** result);
+
   // Returns true iff the named file exists.
   virtual bool FileExists(const std::string& fname) = 0;
 
@@ -289,6 +304,9 @@ class EnvWrapper : public Env {
   Status NewWritableFile(const std::string& f, WritableFile** r) {
     return target_->NewWritableFile(f, r);
   }
+  Status NewAppendableFile(const std::string& f, WritableFile** r) {
+    return target_->NewAppendableFile(f, r);
+  }
   bool FileExists(const std::string& f) { return target_->FileExists(f); }
   Status GetChildren(const std::string& dir, std::vector<std::string>* r) {
     return target_->GetChildren(dir, r);