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63 lines
1.5 KiB
63 lines
1.5 KiB
#include "table/blob_file.h"
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#include "util/coding.h"
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#include "util/crc32c.h"
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#include <cassert>
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namespace leveldb {
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namespace blob {
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BlobFile::BlobFile(WritableFile* dest) : dest_(dest), head_(0) {}
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BlobFile::BlobFile(WritableFile* dest, uint64_t dest_length)
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: dest_(dest), head_(dest_length) {}
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BlobFile::~BlobFile() = default;
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Status BlobFile::AddRecord(const Slice& key, const Slice& value, uint64_t& offset) {
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// 动态写入记录，返回写入的偏移量
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return EmitDynamicRecord(key, value, offset);
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}
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Status BlobFile::EmitDynamicRecord(const Slice& key, const Slice& value, uint64_t& offset) {
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// 记录头部，包括 key 和 value 的长度
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char header[8]; // 4 字节 key 长度 + 4 字节 value 长度
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uint32_t key_size = static_cast<uint32_t>(key.size());
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uint32_t value_size = static_cast<uint32_t>(value.size());
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// 编码 key 和 value 长度
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EncodeFixed32(header, key_size);
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EncodeFixed32(header + 4, value_size);
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// 写入头部
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Status s = dest_->Append(Slice(header, sizeof(header)));
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if (!s.ok()) {
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return s;
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}
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// 写入 key 和 value 数据
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s = dest_->Append(key);
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if (!s.ok()) {
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return s;
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}
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s = dest_->Append(value);
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if (!s.ok()) {
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return s;
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}
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// 刷新文件到磁盘
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s = dest_->Flush();
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if (!s.ok()) {
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return s;
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}
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// 更新偏移量
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offset = head_;
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head_ += sizeof(header) + key_size + value_size;
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return Status::OK();
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}
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} // namespace blob
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} // namespace leveldb
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