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47 lines
1.1 KiB
C++
47 lines
1.1 KiB
C++
#pragma once
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#include <IO/ReadBufferFromFileDescriptor.h>
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#include <Common/CurrentMetrics.h>
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#ifndef O_DIRECT
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#define O_DIRECT 00040000
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#endif
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namespace CurrentMetrics
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{
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extern const Metric OpenFileForRead;
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}
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namespace DB
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{
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/** Accepts path to file and opens it, or pre-opened file descriptor.
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* Closes file by himself (thus "owns" a file descriptor).
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*/
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class ReadBufferFromFile : public ReadBufferFromFileDescriptor
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{
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protected:
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std::string file_name;
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CurrentMetrics::Increment metric_increment{CurrentMetrics::OpenFileForRead};
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public:
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ReadBufferFromFile(const std::string & file_name_, size_t buf_size = DBMS_DEFAULT_BUFFER_SIZE, int flags = -1,
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char * existing_memory = nullptr, size_t alignment = 0);
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/// Use pre-opened file descriptor.
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ReadBufferFromFile(int fd, const std::string & original_file_name = {}, size_t buf_size = DBMS_DEFAULT_BUFFER_SIZE,
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char * existing_memory = nullptr, size_t alignment = 0);
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~ReadBufferFromFile() override;
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/// Close file before destruction of object.
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void close();
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std::string getFileName() const override
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{
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return file_name;
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}
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};
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}
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