Added compact option to Environment.CopyTo

Author: ilyalukyanov

src/LightningDB.Tests/EnvironmentTests.cs

@@ -90,15 +90,16 @@ public void EnvironmentShouldBeClosed()
             Assert.AreEqual(false, _env.IsOpened);
         }
 
-        [Test]
-        public void EnvironmentShouldBeCopied()
+        [TestCase(true)]
+        [TestCase(false)]
+        public void EnvironmentShouldBeCopied(bool compact)
         {
             //arrange
             _env = new LightningEnvironment(_path, EnvironmentOpenFlags.None);
             _env.Open(); 
 
             //act
-            _env.CopyTo(_pathCopy);
+            _env.CopyTo(_pathCopy, compact);
 
             //assert
             if (Directory.GetFiles(_pathCopy).Length == 0)

src/LightningDB/EnvironmentCopyFlags.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace LightningDB
+{
+    public enum EnvironmentCopyFlags
+    {
+        None = 0,
+
+        /// <summary>
+        /// MDB_CP_COMPACT. Compacting copy: Omit free space from copy, and renumber all pages sequentially.
+        /// </summary>
+        Compact = 0x01
+    }
+}

src/LightningDB/LightningDB.csproj

@@ -74,6 +74,7 @@
     <Compile Include="Collections\CursorEnumerator.cs" />
     <Compile Include="CursorGetByOperation.cs" />
     <Compile Include="CursorPutOptions.cs" />
+    <Compile Include="EnvironmentCopyFlags.cs" />
     <Compile Include="Factories\CursorManager.cs" />
     <Compile Include="Factories\DatabaseHandleCacheEntry.cs" />
     <Compile Include="Factories\DatabaseManager.cs" />

src/LightningDB/LightningEnvironment.cs

@@ -289,11 +289,16 @@ internal LightningDatabase OpenDatabase(string name, LightningTransaction tran,
         /// This function may be used to make a backup of an existing environment.
         /// </summary>
         /// <param name="path">The directory in which the copy will reside. This directory must already exist and be writable but must otherwise be empty.</param>
-        public void CopyTo(string path)
+        /// <param name="compact">Omit empty pages when copying.</param>
+        public void CopyTo(string path, bool compact = false)
         {
             this.EnsureOpened();
 
-            NativeMethods.Execute(lib => lib.mdb_env_copy(_handle, path));
+            var flags = compact 
+                ? EnvironmentCopyFlags.Compact 
+                : EnvironmentCopyFlags.None;
+            
+            NativeMethods.Execute(lib => lib.mdb_env_copy2(_handle, path, flags));
         }
 
         //TODO: tests

src/LightningDB/Native/INativeLibraryFacade.cs

@@ -303,7 +303,18 @@ interface INativeLibraryFacade
         /// <param name="env">An environment handle returned by mdb_env_create(). It must have already been opened successfully.</param>
         /// <param name="path">The directory in which the copy will reside. This directory must already exist and be writable but must otherwise be empty.</param>
         /// <returns>A non-zero error value on failure and 0 on success.</returns>
-        int mdb_env_copy(IntPtr env, string path); //OK
+        int mdb_env_copy(IntPtr env, string path);
+
+        /// <summary>
+        /// Copy an LMDB environment to the specified path, with options.
+        /// This function may be used to make a backup of an existing environment. No lockfile is created, since it gets recreated at need.
+        /// This call can trigger significant file size growth if run in parallel with write transactions, because it employs a read-only transaction.
+        /// </summary>
+        /// <param name="env">An environment handle returned by mdb_env_create(). It must have already been opened successfully.</param>
+        /// <param name="path">The directory in which the copy will reside. This directory must already exist and be writable but must otherwise be empty.</param>
+        /// <param name="copyFlags">Special options for this operation. This parameter must be set to 0 or by bitwise OR'ing together one or more of the values described here.</param>
+        /// <returns>A non-zero error value on failure and 0 on success.</returns>
+        int mdb_env_copy2(IntPtr env, string path, EnvironmentCopyFlags copyFlags);
 
         /// <summary>
         /// Return information about the LMDB environment.

src/LightningDB/Native/NativeLibraryFacades.cs

@@ -73,6 +73,9 @@ class Native32BitLibraryFacade : INativeLibraryFacade
         [DllImport(LibraryName, CallingConvention = CallingConvention.Cdecl)]
         private static extern int mdb_env_copy(IntPtr env, string path);
 
+        [DllImport(LibraryName, CallingConvention = CallingConvention.Cdecl)]
+        private static extern int mdb_env_copy2(IntPtr env, string path, EnvironmentCopyFlags copyFlags);
+
         [DllImport(LibraryName, CallingConvention = CallingConvention.Cdecl)]
         private static extern int mdb_env_info (IntPtr env, out MDBEnvInfo stat);
 
@@ -226,6 +229,11 @@ int INativeLibraryFacade.mdb_env_copy(IntPtr env, string path)
             return Native32BitLibraryFacade.mdb_env_copy(env, path);
         }
 
+        int INativeLibraryFacade.mdb_env_copy2(IntPtr env, string path, EnvironmentCopyFlags copyFlags)
+        {
+            return Native32BitLibraryFacade.mdb_env_copy2(env, path, copyFlags);
+        }
+
         int INativeLibraryFacade.mdb_env_info (IntPtr env, out MDBEnvInfo stat)
         {
             return Native32BitLibraryFacade.mdb_env_info(env, out stat);
@@ -358,6 +366,9 @@ class Native64BitLibraryFacade : INativeLibraryFacade
         [DllImport(LibraryName, CallingConvention = CallingConvention.Cdecl)]
         private static extern int mdb_env_copy(IntPtr env, string path);
 
+        [DllImport(LibraryName, CallingConvention = CallingConvention.Cdecl)]
+        private static extern int mdb_env_copy2(IntPtr env, string path, EnvironmentCopyFlags copyFlags);
+
         [DllImport(LibraryName, CallingConvention = CallingConvention.Cdecl)]
         private static extern int mdb_env_info (IntPtr env, out MDBEnvInfo stat);
 
@@ -499,6 +510,11 @@ int INativeLibraryFacade.mdb_env_copy(IntPtr env, string path)
             return Native64BitLibraryFacade.mdb_env_copy(env, path);
         }
 
+        int INativeLibraryFacade.mdb_env_copy2(IntPtr env, string path, EnvironmentCopyFlags copyFlags)
+        {
+            return Native64BitLibraryFacade.mdb_env_copy2(env, path, copyFlags);
+        }
+
         int INativeLibraryFacade.mdb_env_info (IntPtr env, out MDBEnvInfo stat)
         {
             return Native64BitLibraryFacade.mdb_env_info(env, out stat);
@@ -631,6 +647,9 @@ class FallbackLibraryFacade : INativeLibraryFacade
         [DllImport(LibraryName, CallingConvention = CallingConvention.Cdecl)]
         private static extern int mdb_env_copy(IntPtr env, string path);
 
+        [DllImport(LibraryName, CallingConvention = CallingConvention.Cdecl)]
+        private static extern int mdb_env_copy2(IntPtr env, string path, EnvironmentCopyFlags copyFlags);
+
         [DllImport(LibraryName, CallingConvention = CallingConvention.Cdecl)]
         private static extern int mdb_env_info (IntPtr env, out MDBEnvInfo stat);
 
@@ -784,6 +803,11 @@ int INativeLibraryFacade.mdb_env_copy(IntPtr env, string path)
             return FallbackLibraryFacade.mdb_env_copy(env, path);
         }
 
+        int INativeLibraryFacade.mdb_env_copy2(IntPtr env, string path, EnvironmentCopyFlags copyFlags)
+        {
+            return FallbackLibraryFacade.mdb_env_copy2(env, path, copyFlags);
+        }
+
         int INativeLibraryFacade.mdb_env_info (IntPtr env, out MDBEnvInfo stat)
         {
             return FallbackLibraryFacade.mdb_env_info(env, out stat);

src/LightningDB/Native/NativeLibraryFacades.tt

@@ -88,6 +88,9 @@ namespace LightningDB.Native
         [DllImport(LibraryName, CallingConvention = CallingConvention.Cdecl)]
         private static extern int mdb_env_copy(IntPtr env, string path);
 
+        [DllImport(LibraryName, CallingConvention = CallingConvention.Cdecl)]
+        private static extern int mdb_env_copy2(IntPtr env, string path, EnvironmentCopyFlags copyFlags);
+
         [DllImport(LibraryName, CallingConvention = CallingConvention.Cdecl)]
         private static extern int mdb_env_info (IntPtr env, out MDBEnvInfo stat);
 
@@ -245,6 +248,11 @@ namespace LightningDB.Native
             return <#= pair.Value #>LibraryFacade.mdb_env_copy(env, path);
         }
 
+        int INativeLibraryFacade.mdb_env_copy2(IntPtr env, string path, EnvironmentCopyFlags copyFlags)
+        {
+            return <#= pair.Value #>LibraryFacade.mdb_env_copy2(env, path, copyFlags);
+        }
+
         int INativeLibraryFacade.mdb_env_info (IntPtr env, out MDBEnvInfo stat)
         {
             return <#= pair.Value #>LibraryFacade.mdb_env_info(env, out stat);