Add readOnly option (#98)

src/database.cc

@@ -33,9 +33,14 @@ Database::~Database () {
 /* Calls from worker threads, NO V8 HERE *****************************/
 
 rocksdb::Status Database::OpenDatabase (
-        rocksdb::Options* options
+        rocksdb::Options* options,
+        bool readOnly
     ) {
-  return rocksdb::DB::Open(*options, **location, &db);
+  if (readOnly) {
+    return rocksdb::DB::OpenForReadOnly(*options, **location, &db);
+  } else {
+    return rocksdb::DB::Open(*options, **location, &db);
+  }
 }
 
 rocksdb::Status Database::PutToDatabase (
@@ -181,6 +186,7 @@ v8::Local<v8::Value> Database::NewInstance (v8::Local<v8::String> &location) {
 NAN_METHOD(Database::Open) {
   LD_METHOD_SETUP_COMMON(open, 0, 1)
 
+  bool readOnly = BooleanOptionValue(optionsObj, "readOnly", false);
   bool createIfMissing = BooleanOptionValue(optionsObj, "createIfMissing", true);
   bool errorIfExists = BooleanOptionValue(optionsObj, "errorIfExists");
   bool compression = BooleanOptionValue(optionsObj, "compression", true);
@@ -217,6 +223,7 @@ NAN_METHOD(Database::Open) {
     , maxOpenFiles
     , blockRestartInterval
     , maxFileSize
+    , readOnly
   );
   // persist to prevent accidental GC
   v8::Local<v8::Object> _this = info.This();

src/database.h

@@ -43,7 +43,7 @@ class Database : public Nan::ObjectWrap {
   static void Init ();
   static v8::Local<v8::Value> NewInstance (v8::Local<v8::String> &location);
 
-  rocksdb::Status OpenDatabase (rocksdb::Options* options);
+  rocksdb::Status OpenDatabase (rocksdb::Options* options, bool readOnly);
   rocksdb::Status PutToDatabase (
       rocksdb::WriteOptions* options
     , rocksdb::Slice key

src/database_async.cc

@@ -36,7 +36,9 @@ OpenWorker::OpenWorker (
   , uint32_t maxOpenFiles
   , uint32_t blockRestartInterval
   , uint32_t maxFileSize
+  , bool readOnly
 ) : AsyncWorker(database, callback, "rocksdb:db.open")
+  , readOnly_(readOnly)
 {
   rocksdb::LevelDBOptions levelOptions;
 
@@ -85,7 +87,7 @@ OpenWorker::~OpenWorker () {
 }
 
 void OpenWorker::Execute () {
-  SetStatus(database->OpenDatabase(options));
+  SetStatus(database->OpenDatabase(options, readOnly_));
 }
 
 /** CLOSE WORKER **/

src/database_async.h

@@ -25,13 +25,15 @@ class OpenWorker : public AsyncWorker {
     , uint32_t maxOpenFiles
     , uint32_t blockRestartInterval
     , uint32_t maxFileSize
+    , bool readOnly
   );
 
   virtual ~OpenWorker ();
   virtual void Execute ();
 
 private:
   rocksdb::Options* options;
+  bool readOnly_;
 };
 
 class CloseWorker : public AsyncWorker {

test/open-read-only-test.js

@@ -0,0 +1,115 @@
+'use strict'
+
+const test = require('tape')
+const leveldown = require('../')
+const testCommon = require('abstract-leveldown/testCommon')
+const fs = require('fs')
+const path = require('path')
+
+var location = testCommon.location()
+
+// This is used because it's not sufficient on windows to set a parent folder as readonly
+function chmodFilesSync (dir, mode) {
+  var files = fs.readdirSync(dir)
+  files.forEach(function (file) {
+    var fullPath = path.join(dir, file)
+    fs.chmodSync(fullPath, mode)
+  })
+}
+
+test('setUp', function (t) {
+  // just in case we thew an error last time and don't have perms to remove db
+  if (fs.existsSync(location)) {
+    fs.chmodSync(location, 0o755)
+    chmodFilesSync(location, 0o755)
+  }
+  testCommon.setUp(t)
+})
+
+test('test write to read/write database', function (t) {
+  var db = leveldown(location)
+  db.open(function (err) {
+    t.error(err)
+    db.put('my key', 'my value', function (err) {
+      t.error(err, 'no write error')
+      db.get('my key', function (err, value) {
+        t.error(err, 'no read error')
+        t.equal(value.toString(), 'my value', 'correct value')
+        db.close(t.end.bind(t))
+      })
+    })
+  })
+})
+
+test('test throw error reading read-only database', function (t) {
+  chmodFilesSync(location, 0o555)
+  fs.chmodSync(location, 0o555)
+  var db = leveldown(location)
+  db.open(function (err) {
+    t.ok(err, 'should get error reading read only database')
+    t.ok(/IO Error/i.test(err && err.message), 'should get io error')
+    db.close(t.end.bind(t))
+  })
+})
+
+test('test read from a read-only database if readOnly is true', function (t) {
+  chmodFilesSync(location, 0o555)
+  fs.chmodSync(location, 0o555)
+  var db = leveldown(location)
+  db.open({ readOnly: true }, function (err) {
+    t.error(err)
+    db.get('my key', function (err, value) {
+      t.error(err, 'no read error')
+      t.equal(value.toString(), 'my value', 'correct value')
+      db.close(t.end.bind(t))
+    })
+  })
+})
+
+test('test throw error reading read-only database if readOnly is false', function (t) {
+  chmodFilesSync(location, 0o555)
+  fs.chmodSync(location, 0o555)
+  var db = leveldown(location)
+  db.open({ readOnly: false }, function (err) {
+    t.ok(err, 'should get error reading read only database')
+    t.ok(/IO Error/i.test(err && err.message), 'should get io error')
+    db.close(t.end.bind(t))
+  })
+})
+
+test('test throw error putting data to read-only db if readOnly is true', function (t) {
+  chmodFilesSync(location, 0o555)
+  fs.chmodSync(location, 0o555)
+  var db = leveldown(location)
+  db.open({ readOnly: true }, function (err) {
+    t.error(err)
+    db.put('my key', 'my value', function (err) {
+      t.ok(err, 'should get write error')
+      t.ok(/Not supported operation in read only mode/i.test(err && err.message), 'should get io error')
+      db.close(t.end.bind(t))
+    })
+  })
+})
+
+test('test throw error deleting data from read-only db if readOnly is true', function (t) {
+  chmodFilesSync(location, 0o555)
+  fs.chmodSync(location, 0o555)
+  var db = leveldown(location)
+  db.open({ readOnly: true }, function (err) {
+    t.error(err)
+    db.del('my key', function (err) {
+      t.ok(err, 'should get write error')
+      t.ok(/Not supported operation in read only mode/i.test(err && err.message), 'should get io error')
+      db.close(t.end.bind(t))
+    })
+  })
+})
+
+test('tearDown', function (t) {
+  // just in case we thew an error last time and don't have perms to remove db
+  if (fs.existsSync(location)) {
+    fs.chmodSync(location, 0o755)
+    chmodFilesSync(location, 0o755)
+  }
+  testCommon.tearDown(t)
+})