Retire memenv https://github.com/facebook/rocksdb/pull/2082
Summary: This is a manual commit of this PR: Retire InMemoryEnv in favor of MockEnv #2082 With MockEnv doing the same yet being more mature, InMemoryEnv is redundant. Reviewed By: IslamAbdelRahman Differential Revision: D5162323 fbshipit-source-id: 59fd0082a891dc99cc531e4da9d68bf891eae3f5main
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#include <string.h> |
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#include <algorithm> |
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#include <map> |
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#include <string> |
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#include <vector> |
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#include "rocksdb/env.h" |
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#include "rocksdb/status.h" |
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#include "port/port.h" |
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#include "util/mutexlock.h" |
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namespace rocksdb { |
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#ifndef ROCKSDB_LITE |
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namespace { |
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std::string NormalizeFileName(const std::string fname) { |
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if (fname.find("//") == std::string::npos) { |
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return fname; |
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} |
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std::string out_name = ""; |
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bool is_slash = false; |
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for (char c : fname) { |
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if (c == '/' && is_slash) { |
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continue; |
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} |
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out_name.append(1, c); |
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if (c == '/') { |
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is_slash = true; |
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} else { |
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is_slash = false; |
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} |
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} |
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return out_name; |
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} |
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class FileState { |
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public: |
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// FileStates are reference counted. The initial reference count is zero
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// and the caller must call Ref() at least once.
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FileState() : refs_(0), size_(0) {} |
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// Increase the reference count.
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void Ref() { |
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MutexLock lock(&refs_mutex_); |
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++refs_; |
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} |
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// Decrease the reference count. Delete if this is the last reference.
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void Unref() { |
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bool do_delete = false; |
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{ |
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MutexLock lock(&refs_mutex_); |
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--refs_; |
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assert(refs_ >= 0); |
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if (refs_ <= 0) { |
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do_delete = true; |
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} |
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} |
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if (do_delete) { |
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delete this; |
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} |
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} |
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uint64_t Size() const { return size_; } |
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Status Read(uint64_t offset, size_t n, Slice* result, char* scratch) const { |
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const uint64_t available = size_ - std::min(size_, offset); |
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if (n > available) { |
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n = available; |
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} |
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if (n == 0) { |
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*result = Slice(); |
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return Status::OK(); |
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} |
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size_t block = offset / kBlockSize; |
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size_t block_offset = offset % kBlockSize; |
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if (n <= kBlockSize - block_offset) { |
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// The requested bytes are all in the first block.
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*result = Slice(blocks_[block] + block_offset, n); |
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return Status::OK(); |
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} |
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size_t bytes_to_copy = n; |
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char* dst = scratch; |
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while (bytes_to_copy > 0) { |
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size_t avail = kBlockSize - block_offset; |
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if (avail > bytes_to_copy) { |
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avail = bytes_to_copy; |
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} |
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memcpy(dst, blocks_[block] + block_offset, avail); |
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bytes_to_copy -= avail; |
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dst += avail; |
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block++; |
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block_offset = 0; |
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} |
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*result = Slice(scratch, n); |
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return Status::OK(); |
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} |
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Status Append(const Slice& data) { |
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const char* src = data.data(); |
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size_t src_len = data.size(); |
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while (src_len > 0) { |
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size_t avail; |
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size_t offset = size_ % kBlockSize; |
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if (offset != 0) { |
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// There is some room in the last block.
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avail = kBlockSize - offset; |
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} else { |
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// No room in the last block; push new one.
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blocks_.push_back(new char[kBlockSize]); |
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avail = kBlockSize; |
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} |
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if (avail > src_len) { |
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avail = src_len; |
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} |
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memcpy(blocks_.back() + offset, src, avail); |
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src_len -= avail; |
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src += avail; |
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size_ += avail; |
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} |
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return Status::OK(); |
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} |
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private: |
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// Private since only Unref() should be used to delete it.
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~FileState() { |
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for (std::vector<char*>::iterator i = blocks_.begin(); i != blocks_.end(); |
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++i) { |
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delete [] *i; |
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} |
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} |
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// No copying allowed.
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FileState(const FileState&); |
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void operator=(const FileState&); |
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port::Mutex refs_mutex_; |
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int refs_; // Protected by refs_mutex_;
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// The following fields are not protected by any mutex. They are only mutable
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// while the file is being written, and concurrent access is not allowed
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// to writable files.
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std::vector<char*> blocks_; |
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uint64_t size_; |
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enum { kBlockSize = 8 * 1024 }; |
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}; |
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class SequentialFileImpl : public SequentialFile { |
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public: |
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explicit SequentialFileImpl(FileState* file) : file_(file), pos_(0) { |
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file_->Ref(); |
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} |
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~SequentialFileImpl() { |
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file_->Unref(); |
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} |
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virtual Status Read(size_t n, Slice* result, char* scratch) override { |
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Status s = file_->Read(pos_, n, result, scratch); |
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if (s.ok()) { |
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pos_ += result->size(); |
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} |
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return s; |
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} |
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virtual Status Skip(uint64_t n) override { |
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if (pos_ > file_->Size()) { |
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return Status::IOError("pos_ > file_->Size()"); |
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} |
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const size_t available = file_->Size() - pos_; |
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if (n > available) { |
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n = available; |
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} |
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pos_ += n; |
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return Status::OK(); |
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} |
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private: |
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FileState* file_; |
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size_t pos_; |
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}; |
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class RandomAccessFileImpl : public RandomAccessFile { |
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public: |
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explicit RandomAccessFileImpl(FileState* file) : file_(file) { |
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file_->Ref(); |
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} |
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~RandomAccessFileImpl() { |
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file_->Unref(); |
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} |
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virtual Status Read(uint64_t offset, size_t n, Slice* result, |
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char* scratch) const override { |
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return file_->Read(offset, n, result, scratch); |
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} |
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private: |
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FileState* file_; |
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}; |
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class WritableFileImpl : public WritableFile { |
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public: |
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explicit WritableFileImpl(FileState* file) : file_(file) { file_->Ref(); } |
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~WritableFileImpl() { |
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file_->Unref(); |
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} |
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virtual Status Append(const Slice& data) override { |
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return file_->Append(data); |
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} |
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virtual Status Truncate(uint64_t size) override { |
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return Status::OK(); |
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} |
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virtual Status Close() override { return Status::OK(); } |
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virtual Status Flush() override { return Status::OK(); } |
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virtual Status Sync() override { return Status::OK(); } |
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private: |
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FileState* file_; |
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}; |
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class InMemoryDirectory : public Directory { |
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public: |
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virtual Status Fsync() override { return Status::OK(); } |
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}; |
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class InMemoryEnv : public EnvWrapper { |
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public: |
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explicit InMemoryEnv(Env* base_env) : EnvWrapper(base_env) { } |
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virtual ~InMemoryEnv() { |
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for (FileSystem::iterator i = file_map_.begin(); i != file_map_.end(); ++i){ |
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i->second->Unref(); |
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} |
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} |
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// Partial implementation of the Env interface.
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virtual Status NewSequentialFile(const std::string& fname, |
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unique_ptr<SequentialFile>* result, |
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const EnvOptions& soptions) override { |
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std::string nfname = NormalizeFileName(fname); |
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MutexLock lock(&mutex_); |
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if (file_map_.find(fname) == file_map_.end()) { |
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*result = NULL; |
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return Status::IOError(fname, "File not found"); |
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} |
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result->reset(new SequentialFileImpl(file_map_[nfname])); |
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return Status::OK(); |
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} |
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virtual Status NewRandomAccessFile(const std::string& fname, |
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unique_ptr<RandomAccessFile>* result, |
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const EnvOptions& soptions) override { |
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std::string nfname = NormalizeFileName(fname); |
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MutexLock lock(&mutex_); |
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if (file_map_.find(nfname) == file_map_.end()) { |
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*result = NULL; |
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return Status::IOError(fname, "File not found"); |
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} |
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result->reset(new RandomAccessFileImpl(file_map_[nfname])); |
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return Status::OK(); |
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} |
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virtual Status NewWritableFile(const std::string& fname, |
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unique_ptr<WritableFile>* result, |
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const EnvOptions& soptions) override { |
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std::string nfname = NormalizeFileName(fname); |
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MutexLock lock(&mutex_); |
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if (file_map_.find(nfname) != file_map_.end()) { |
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DeleteFileInternal(nfname); |
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} |
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FileState* file = new FileState(); |
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file->Ref(); |
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file_map_[nfname] = file; |
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result->reset(new WritableFileImpl(file)); |
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return Status::OK(); |
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} |
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virtual Status NewDirectory(const std::string& name, |
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unique_ptr<Directory>* result) override { |
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result->reset(new InMemoryDirectory()); |
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return Status::OK(); |
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} |
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virtual Status FileExists(const std::string& fname) override { |
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std::string nfname = NormalizeFileName(fname); |
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MutexLock lock(&mutex_); |
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if (file_map_.find(nfname) != file_map_.end()) { |
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return Status::OK(); |
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} else { |
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return Status::NotFound(); |
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} |
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} |
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virtual Status GetChildren(const std::string& dir, |
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std::vector<std::string>* result) override { |
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MutexLock lock(&mutex_); |
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result->clear(); |
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bool found_dir = false; |
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for (FileSystem::iterator i = file_map_.begin(); i != file_map_.end(); ++i){ |
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const std::string& filename = i->first; |
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if (dir == filename) { |
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found_dir = true; |
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} else if (filename.size() >= dir.size() + 1 && |
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filename[dir.size()] == '/' && |
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Slice(filename).starts_with(Slice(dir))) { |
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found_dir = true; |
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result->push_back(filename.substr(dir.size() + 1)); |
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} |
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} |
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return found_dir ? Status::OK() : Status::NotFound(); |
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} |
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void DeleteFileInternal(const std::string& fname) { |
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if (file_map_.find(fname) == file_map_.end()) { |
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return; |
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} |
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file_map_[fname]->Unref(); |
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file_map_.erase(fname); |
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} |
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virtual Status DeleteFile(const std::string& fname) override { |
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std::string nfname = NormalizeFileName(fname); |
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MutexLock lock(&mutex_); |
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if (file_map_.find(nfname) == file_map_.end()) { |
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return Status::IOError(fname, "File not found"); |
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} |
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DeleteFileInternal(nfname); |
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return Status::OK(); |
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} |
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virtual Status CreateDir(const std::string& dirname) override { |
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auto ndirname = NormalizeFileName(dirname); |
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if (file_map_.find(ndirname) == file_map_.end()) { |
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FileState* file = new FileState(); |
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file->Ref(); |
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file_map_[ndirname] = file; |
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} else { |
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return Status::IOError(); |
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} |
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return Status::OK(); |
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} |
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virtual Status CreateDirIfMissing(const std::string& dirname) override { |
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CreateDir(dirname); |
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return Status::OK(); |
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} |
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virtual Status DeleteDir(const std::string& dirname) override { |
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return DeleteFile(dirname); |
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} |
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virtual Status GetFileSize(const std::string& fname, |
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uint64_t* file_size) override { |
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std::string nfname = NormalizeFileName(fname); |
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MutexLock lock(&mutex_); |
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if (file_map_.find(nfname) == file_map_.end()) { |
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return Status::IOError(fname, "File not found"); |
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} |
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*file_size = file_map_[nfname]->Size(); |
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return Status::OK(); |
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} |
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virtual Status GetFileModificationTime(const std::string& fname, |
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uint64_t* time) override { |
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return Status::NotSupported("getFileMTime", "Not supported in MemEnv"); |
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} |
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virtual Status RenameFile(const std::string& src, |
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const std::string& dest) override { |
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std::string nsrc = NormalizeFileName(src); |
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std::string ndest = NormalizeFileName(dest); |
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MutexLock lock(&mutex_); |
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if (file_map_.find(nsrc) == file_map_.end()) { |
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return Status::IOError(src, "File not found"); |
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} |
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DeleteFileInternal(dest); |
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file_map_[ndest] = file_map_[nsrc]; |
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file_map_.erase(nsrc); |
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return Status::OK(); |
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} |
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virtual Status LockFile(const std::string& fname, FileLock** lock) override { |
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*lock = new FileLock; |
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return Status::OK(); |
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} |
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virtual Status UnlockFile(FileLock* lock) override { |
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delete lock; |
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return Status::OK(); |
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} |
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virtual Status GetTestDirectory(std::string* path) override { |
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*path = "/test"; |
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return Status::OK(); |
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} |
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private: |
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// Map from filenames to FileState objects, representing a simple file system.
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typedef std::map<std::string, FileState*> FileSystem; |
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port::Mutex mutex_; |
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FileSystem file_map_; // Protected by mutex_.
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}; |
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} // namespace
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Env* NewMemEnv(Env* base_env) { |
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return new InMemoryEnv(base_env); |
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} |
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#else // ROCKSDB_LITE
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Env* NewMemEnv(Env* base_env) { return nullptr; } |
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#endif // !ROCKSDB_LITE
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} // namespace rocksdb
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