85 lines
2.9 KiB
C
85 lines
2.9 KiB
C
#include <lladd/transactional.h>
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#define stasis_handle(x) stasis_handle_##x
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/**
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Error handling:
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read, write, append, open, release_read_buffer and
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release_write_buffer return 0 on success, and an error code
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otherwise. read_buffer() and write_buffer() return error codes via
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the error field of the handles they produce.
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Errors in num_copies, num_copies_buffer, start_position, and end_position
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are always unrecoverable, and return -1.
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Here are the meanings of the various error codes:
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EDOM off is less than the beginning of the file (possibly due to truncation).
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EBADF an unrecoverable error occurred; the handle is no longer vaild. The error
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that caused this one is stored in the handle's error field.
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Handle implementations may return return other errors as appropriate.
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*/
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typedef struct stasis_handle_t {
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/** @return the number of in-memory copies made when the caller
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provides the buffer */
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int (*num_copies)(struct stasis_handle_t * h);
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/** @return the number of in-memory copies made when the handle
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provides the buffer */
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int (*num_copies_buffer)(struct stasis_handle_t * h);
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int (*close)(struct stasis_handle_t *);
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/** The offset of the handle's first byte */
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lsn_t (*start_position)(struct stasis_handle_t * h);
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/** The offset of the byte after the end of the handle's data. */
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lsn_t (*end_position)(struct stasis_handle_t * h);
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struct stasis_write_buffer_t * (*write_buffer)(struct stasis_handle_t * h,
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lsn_t off, lsn_t len);
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struct stasis_write_buffer_t * (*append_buffer)(struct stasis_handle_t * h,
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lsn_t len);
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int (*release_write_buffer)(struct stasis_write_buffer_t * w);
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struct stasis_read_buffer_t * (*read_buffer)(struct stasis_handle_t * h,
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lsn_t offset, lsn_t length);
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int (*release_read_buffer)(struct stasis_read_buffer_t * r);
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int (*write)(struct stasis_handle_t * h, lsn_t off,
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const byte * dat, lsn_t len);
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int (*append)(struct stasis_handle_t * h, lsn_t * off, const byte * dat, lsn_t len);
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int (*read)(struct stasis_handle_t * h,
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lsn_t offset, byte * buf, lsn_t length);
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int (*truncate_start)(struct stasis_handle_t * h, lsn_t new_start);
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int error;
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void * impl;
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} stasis_handle_t;
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typedef struct stasis_write_buffer_t {
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stasis_handle_t * h;
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lsn_t off;
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byte * buf;
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lsn_t len;
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void * impl;
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int error;
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} stasis_write_buffer_t;
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typedef struct stasis_read_buffer_t {
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stasis_handle_t * h;
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const byte * buf;
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lsn_t len;
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void * impl;
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int error;
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} stasis_read_buffer_t;
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stasis_handle_t * stasis_handle(open_memory)(void);
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stasis_handle_t * stasis_handle(open_file)(char * path, int mode);
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stasis_handle_t * stasis_handle(open_non_blocking)(stasis_handle_t * h,
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int worker_thread_count);
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stasis_handle_t * stasis_handle(open_verifying)(stasis_handle_t * h);
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stasis_handle_t * stasis_handle(open_debug)(stasis_handle_t * h);
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