Native Windows LevelDB port

Import native Windows LevelDB port by Hiram Chirino.

Extracted from from https://github.com/chirino/leveldb.git using
git diff dd0d562..aea83b7

3 files changed, 310 insertions, 0 deletions

diff --git a/src/leveldb/port/port.h b/src/leveldb/port/port.h
index e667db40d0..4baafa8e22 100644
--- a/src/leveldb/port/port.h
+++ b/src/leveldb/port/port.h
@@ -14,6 +14,8 @@
 #  include "port/port_posix.h"
 #elif defined(LEVELDB_PLATFORM_CHROMIUM)
 #  include "port/port_chromium.h"
+#elif defined(LEVELDB_PLATFORM_WINDOWS)
+#  include "port/port_win.h"
 #endif
 
 #endif  // STORAGE_LEVELDB_PORT_PORT_H_
diff --git a/src/leveldb/port/port_win.cc b/src/leveldb/port/port_win.cc
new file mode 100644
index 0000000000..7cf9537937
--- /dev/null
+++ b/src/leveldb/port/port_win.cc
@@ -0,0 +1,154 @@
+// LevelDB Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+//
+// See port_example.h for documentation for the following types/functions.
+
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+// 
+//  * Redistributions of source code must retain the above copyright
+//    notice, this list of conditions and the following disclaimer.
+//  * Redistributions in binary form must reproduce the above copyright
+//    notice, this list of conditions and the following disclaimer in the
+//    documentation and/or other materials provided with the distribution.
+//  * Neither the name of the University of California, Berkeley nor the
+//    names of its contributors may be used to endorse or promote products
+//    derived from this software without specific prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
+// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+
+#include "port/port_win.h"
+
+#include <windows.h>
+#include <cassert>
+
+namespace leveldb {
+namespace port {
+
+Mutex::Mutex() :
+    cs_(nullptr) {
+  assert(!cs_);
+  cs_ = static_cast<void *>(new CRITICAL_SECTION());
+  ::InitializeCriticalSection(static_cast<CRITICAL_SECTION *>(cs_));
+  assert(cs_);
+}
+
+Mutex::~Mutex() {
+  assert(cs_);
+  ::DeleteCriticalSection(static_cast<CRITICAL_SECTION *>(cs_));
+  delete static_cast<CRITICAL_SECTION *>(cs_);
+  cs_ = nullptr;
+  assert(!cs_);
+}
+
+void Mutex::Lock() {
+  assert(cs_);
+  ::EnterCriticalSection(static_cast<CRITICAL_SECTION *>(cs_));
+}
+
+void Mutex::Unlock() {
+  assert(cs_);
+  ::LeaveCriticalSection(static_cast<CRITICAL_SECTION *>(cs_));
+}
+
+void Mutex::AssertHeld() {
+  assert(cs_);
+  assert(1);
+}
+
+CondVar::CondVar(Mutex* mu) :
+    waiting_(0), 
+    mu_(mu), 
+    sem1_(::CreateSemaphore(NULL, 0, 10000, NULL)), 
+    sem2_(::CreateSemaphore(NULL, 0, 10000, NULL)) {
+  assert(mu_);
+}
+
+CondVar::~CondVar() {
+  ::CloseHandle(sem1_);
+  ::CloseHandle(sem2_);
+}
+
+void CondVar::Wait() {
+  mu_->AssertHeld();
+
+  wait_mtx_.Lock();
+  ++waiting_;
+  wait_mtx_.Unlock();
+
+  mu_->Unlock();
+
+  // initiate handshake
+  ::WaitForSingleObject(sem1_, INFINITE);
+  ::ReleaseSemaphore(sem2_, 1, NULL);
+  mu_->Lock();
+}
+
+void CondVar::Signal() {
+  wait_mtx_.Lock();
+  if (waiting_ > 0) {
+    --waiting_;
+
+    // finalize handshake
+    ::ReleaseSemaphore(sem1_, 1, NULL);
+    ::WaitForSingleObject(sem2_, INFINITE);
+  }
+  wait_mtx_.Unlock();
+}
+
+void CondVar::SignalAll() {
+  wait_mtx_.Lock();
+  for(long i = 0; i < waiting_; ++i) {
+    ::ReleaseSemaphore(sem1_, 1, NULL);
+    while(waiting_ > 0) {
+      --waiting_;
+      ::WaitForSingleObject(sem2_, INFINITE);
+    }
+  }
+  wait_mtx_.Unlock();
+}
+
+AtomicPointer::AtomicPointer(void* v) {
+  Release_Store(v);
+}
+
+BOOL CALLBACK InitHandleFunction (PINIT_ONCE InitOnce, PVOID func, PVOID *lpContext) {
+  ((void (*)())func)();
+  return true;
+}
+
+void InitOnce(OnceType* once, void (*initializer)()) {
+  InitOnceExecuteOnce((PINIT_ONCE)once, InitHandleFunction, initializer, NULL);
+}
+
+void* AtomicPointer::Acquire_Load() const {
+  void * p = nullptr;
+  InterlockedExchangePointer(&p, rep_);
+  return p;
+}
+
+void AtomicPointer::Release_Store(void* v) {
+  InterlockedExchangePointer(&rep_, v);
+}
+
+void* AtomicPointer::NoBarrier_Load() const {
+  return rep_;
+}
+
+void AtomicPointer::NoBarrier_Store(void* v) {
+  rep_ = v;
+}
+
+}
+}
diff --git a/src/leveldb/port/port_win.h b/src/leveldb/port/port_win.h
new file mode 100644
index 0000000000..c9e1cdad60
--- /dev/null
+++ b/src/leveldb/port/port_win.h
@@ -0,0 +1,154 @@
+// LevelDB Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+//
+// See port_example.h for documentation for the following types/functions.
+
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+// 
+//  * Redistributions of source code must retain the above copyright
+//    notice, this list of conditions and the following disclaimer.
+//  * Redistributions in binary form must reproduce the above copyright
+//    notice, this list of conditions and the following disclaimer in the
+//    documentation and/or other materials provided with the distribution.
+//  * Neither the name of the University of California, Berkeley nor the
+//    names of its contributors may be used to endorse or promote products
+//    derived from this software without specific prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
+// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+
+#ifndef STORAGE_LEVELDB_PORT_PORT_WIN_H_
+#define STORAGE_LEVELDB_PORT_PORT_WIN_H_
+
+#define snprintf _snprintf
+#define close _close
+#define fread_unlocked _fread_nolock
+
+#include <string>
+#include <stdint.h>
+#ifdef SNAPPY
+#include <snappy.h>
+#endif
+
+namespace leveldb {
+namespace port {
+
+// Windows is little endian (for now :p)
+static const bool kLittleEndian = true;
+
+class CondVar;
+
+class Mutex {
+ public:
+  Mutex();
+  ~Mutex();
+
+  void Lock();
+  void Unlock();
+  void AssertHeld();
+
+ private:
+  friend class CondVar;
+  // critical sections are more efficient than mutexes
+  // but they are not recursive and can only be used to synchronize threads within the same process
+  // we use opaque void * to avoid including windows.h in port_win.h
+  void * cs_;
+
+  // No copying
+  Mutex(const Mutex&);
+  void operator=(const Mutex&);
+};
+
+// the Win32 API offers a dependable condition variable mechanism, but only starting with
+// Windows 2008 and Vista
+// no matter what we will implement our own condition variable with a semaphore
+// implementation as described in a paper written by Andrew D. Birrell in 2003
+class CondVar {
+ public:
+  explicit CondVar(Mutex* mu);
+  ~CondVar();
+  void Wait();
+  void Signal();
+  void SignalAll();
+ private:
+  Mutex* mu_;
+  
+  Mutex wait_mtx_;
+  long waiting_;
+  
+  void * sem1_;
+  void * sem2_;
+  
+  
+};
+
+typedef void* OnceType;
+#define LEVELDB_ONCE_INIT 0
+extern void InitOnce(port::OnceType*, void (*initializer)());
+
+// Storage for a lock-free pointer
+class AtomicPointer {
+ private:
+  void * rep_;
+ public:
+  AtomicPointer() : rep_(nullptr) { }
+  explicit AtomicPointer(void* v); 
+  void* Acquire_Load() const;
+
+  void Release_Store(void* v);
+
+  void* NoBarrier_Load() const;
+
+  void NoBarrier_Store(void* v);
+};
+
+inline bool Snappy_Compress(const char* input, size_t length,
+                            ::std::string* output) {
+#ifdef SNAPPY
+  output->resize(snappy::MaxCompressedLength(length));
+  size_t outlen;
+  snappy::RawCompress(input, length, &(*output)[0], &outlen);
+  output->resize(outlen);
+  return true;
+#endif
+
+  return false;
+}
+
+inline bool Snappy_GetUncompressedLength(const char* input, size_t length,
+                                         size_t* result) {
+#ifdef SNAPPY
+  return snappy::GetUncompressedLength(input, length, result);
+#else
+  return false;
+#endif
+}
+
+inline bool Snappy_Uncompress(const char* input, size_t length,
+                              char* output) {
+#ifdef SNAPPY
+  return snappy::RawUncompress(input, length, output);
+#else
+  return false;
+#endif
+}
+
+inline bool GetHeapProfile(void (*func)(void*, const char*, int), void* arg) {
+  return false;
+}
+
+}
+}
+
+#endif  // STORAGE_LEVELDB_PORT_PORT_WIN_H_