From e31f4332276edb9b71272d26c2c0296cf8117101 Mon Sep 17 00:00:00 2001
From: Gordon Hall <gordon@gordonwritescode.com>
Date: Mon, 30 Jan 2017 15:47:50 -0500
Subject: [PATCH] start working on exposing compactRange from leveldb

---
 leveldown.js          |  5 +++++
 src/database.cc       | 29 +++++++++++++++++++++++++++++
 src/database.h        |  2 ++
 src/database_async.cc | 40 ++++++++++++++++++++++++++++++++++++++++
 src/database_async.h  | 22 ++++++++++++++++++++++
 5 files changed, 98 insertions(+)

diff --git a/leveldown.js b/leveldown.js
index beb1e4c0..477654bb 100644
--- a/leveldown.js
+++ b/leveldown.js
@@ -58,6 +58,11 @@ LevelDOWN.prototype._approximateSize = function (start, end, callback) {
 }
 
 
+LevelDOWN.prototype.compactRange = function (start, end, callback) {
+  this.binding.compactRange(start, end, callback)
+}
+
+
 LevelDOWN.prototype.getProperty = function (property) {
   if (typeof property != 'string')
     throw new Error('getProperty() requires a valid `property` argument')
diff --git a/src/database.cc b/src/database.cc
index a799e054..647960a5 100644
--- a/src/database.cc
+++ b/src/database.cc
@@ -79,6 +79,11 @@ uint64_t Database::ApproximateSizeFromDatabase (const leveldb::Range* range) {
   return size;
 }
 
+void Database::CompactRangeFromDatabase (const leveldb::Slice* start, 
+                                         const leveldb::Slice* end) {
+  db->CompactRange(start, end);
+}
+
 void Database::GetPropertyFromDatabase (
       const leveldb::Slice& property
     , std::string* value) {
@@ -143,6 +148,7 @@ void Database::Init () {
   Nan::SetPrototypeMethod(tpl, "del", Database::Delete);
   Nan::SetPrototypeMethod(tpl, "batch", Database::Batch);
   Nan::SetPrototypeMethod(tpl, "approximateSize", Database::ApproximateSize);
+  Nan::SetPrototypeMethod(tpl, "compactRange", Database::CompactRange);
   Nan::SetPrototypeMethod(tpl, "getProperty", Database::GetProperty);
   Nan::SetPrototypeMethod(tpl, "iterator", Database::Iterator);
 }
@@ -430,6 +436,29 @@ NAN_METHOD(Database::ApproximateSize) {
   Nan::AsyncQueueWorker(worker);
 }
 
+NAN_METHOD(Database::CompactRange) {
+  v8::Local<v8::Object> startHandle = info[0].As<v8::Object>();
+  v8::Local<v8::Object> endHandle = info[1].As<v8::Object>();
+
+  LD_METHOD_SETUP_COMMON(compactRange, -1, 2)
+
+  LD_STRING_OR_BUFFER_TO_SLICE(start, startHandle, start)
+  LD_STRING_OR_BUFFER_TO_SLICE(end, endHandle, end)
+
+  CompactRangeWorker* worker  = new CompactRangeWorker(
+      database
+    , new Nan::Callback(callback)
+    , start
+    , end
+    , startHandle
+    , endHandle
+  );
+  // persist to prevent accidental GC
+  v8::Local<v8::Object> _this = info.This();
+  worker->SaveToPersistent("database", _this);
+  Nan::AsyncQueueWorker(worker);
+}
+
 NAN_METHOD(Database::GetProperty) {
   v8::Local<v8::Value> propertyHandle = info[0].As<v8::Object>();
   v8::Local<v8::Function> callback; // for LD_STRING_OR_BUFFER_TO_SLICE
diff --git a/src/database.h b/src/database.h
index e16e6c70..25a68e22 100644
--- a/src/database.h
+++ b/src/database.h
@@ -68,6 +68,7 @@ class Database : public Nan::ObjectWrap {
     , leveldb::WriteBatch* batch
   );
   uint64_t ApproximateSizeFromDatabase (const leveldb::Range* range);
+  void CompactRangeFromDatabase (const leveldb::Slice* start, const leveldb::Slice* end);
   void GetPropertyFromDatabase (const leveldb::Slice& property, std::string* value);
   leveldb::Iterator* NewIterator (leveldb::ReadOptions* options);
   const leveldb::Snapshot* NewSnapshot ();
@@ -101,6 +102,7 @@ class Database : public Nan::ObjectWrap {
   static NAN_METHOD(Write);
   static NAN_METHOD(Iterator);
   static NAN_METHOD(ApproximateSize);
+  static NAN_METHOD(CompactRange);
   static NAN_METHOD(GetProperty);
 };
 
diff --git a/src/database_async.cc b/src/database_async.cc
index a15efaa3..0408c072 100644
--- a/src/database_async.cc
+++ b/src/database_async.cc
@@ -267,4 +267,44 @@ void ApproximateSizeWorker::HandleOKCallback () {
   callback->Call(2, argv);
 }
 
+/** COMPACT RANGE WORKER **/
+
+CompactRangeWorker::CompactRangeWorker (
+    Database *database
+  , Nan::Callback *callback
+  , leveldb::Slice start
+  , leveldb::Slice end
+  , v8::Local<v8::Object> &startHandle
+  , v8::Local<v8::Object> &endHandle
+) : AsyncWorker(database, callback)
+{
+  Nan::HandleScope scope;
+
+  SaveToPersistent("start", startHandle);
+  SaveToPersistent("end", endHandle);
+};
+
+CompactRangeWorker::~CompactRangeWorker () {}
+
+void CompactRangeWorker::Execute () {
+  database->CompactRangeFromDatabase(&start, &end);
+}
+
+void CompactRangeWorker::WorkComplete() {
+  Nan::HandleScope scope;
+
+  DisposeStringOrBufferFromSlice(GetFromPersistent("start"), start);
+  DisposeStringOrBufferFromSlice(GetFromPersistent("end"), end);
+  AsyncWorker::WorkComplete();
+}
+
+void CompactRangeWorker::HandleOKCallback () {
+  Nan::HandleScope scope;
+
+  v8::Local<v8::Value> argv[] = {
+      Nan::Null()
+  };
+  callback->Call(1, argv);
+}
+
 } // namespace leveldown
diff --git a/src/database_async.h b/src/database_async.h
index a501f5a1..09b6205a 100644
--- a/src/database_async.h
+++ b/src/database_async.h
@@ -162,6 +162,28 @@ class ApproximateSizeWorker : public AsyncWorker {
     uint64_t size;
 };
 
+class CompactRangeWorker : public AsyncWorker {
+public:
+  CompactRangeWorker (
+      Database *database
+    , Nan::Callback *callback
+    , leveldb::Slice start
+    , leveldb::Slice end
+    , v8::Local<v8::Object> &startHandle
+    , v8::Local<v8::Object> &endHandle
+  );
+
+  virtual ~CompactRangeWorker ();
+  virtual void Execute ();
+  virtual void HandleOKCallback ();
+  virtual void WorkComplete ();
+
+  private:
+    leveldb::Slice start;
+    leveldb::Slice end;
+};
+
+
 } // namespace leveldown
 
 #endif