ClickHouse/dbms/include/DB/IO/WriteBufferFromFile.h

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#pragma once
#include <sys/types.h>
#include <DB/Common/CurrentMetrics.h>
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#include <DB/IO/WriteBufferFromFileDescriptor.h>
namespace CurrentMetrics
{
extern const Metric OpenFileForWrite;
}
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#ifndef O_DIRECT
#define O_DIRECT 00040000
#endif
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namespace DB
{
/** Accepts path to file and opens it, or pre-opened file descriptor.
* Closes file by himself (thus "owns" a file descriptor).
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*/
class WriteBufferFromFile : public WriteBufferFromFileDescriptor
{
private:
std::string file_name;
CurrentMetrics::Increment metric_increment{CurrentMetrics::OpenFileForWrite};
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public:
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WriteBufferFromFile(
const std::string & file_name_,
size_t buf_size = DBMS_DEFAULT_BUFFER_SIZE,
int flags = -1,
mode_t mode = 0666,
char * existing_memory = nullptr,
size_t alignment = 0);
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/// Use pre-opened file descriptor.
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WriteBufferFromFile(
int fd,
size_t buf_size = DBMS_DEFAULT_BUFFER_SIZE,
int flags = -1,
mode_t mode = 0666,
char * existing_memory = nullptr,
size_t alignment = 0);
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~WriteBufferFromFile() 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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{
return file_name;
}
};
}