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/*-------------------------------------------------------------------------
*
* filemap.h
*
* Copyright (c) 2013-2021, PostgreSQL Global Development Group
*-------------------------------------------------------------------------
*/
#ifndef FILEMAP_H
#define FILEMAP_H
#include "datapagemap.h"
#include "storage/block.h"
#include "storage/relfilenode.h"
/* these enum values are sorted in the order we want actions to be processed */
typedef enum
{
FILE_ACTION_UNDECIDED = 0, /* not decided yet */
FILE_ACTION_CREATE, /* create local directory or symbolic link */
FILE_ACTION_COPY, /* copy whole file, overwriting if exists */
FILE_ACTION_COPY_TAIL, /* copy tail from 'source_size' to
* 'target_size' */
FILE_ACTION_NONE, /* no action (we might still copy modified
* blocks based on the parsed WAL) */
FILE_ACTION_TRUNCATE, /* truncate local file to 'newsize' bytes */
FILE_ACTION_REMOVE /* remove local file / directory / symlink */
} file_action_t;
typedef enum
{
FILE_TYPE_UNDEFINED = 0,
FILE_TYPE_REGULAR,
FILE_TYPE_DIRECTORY,
FILE_TYPE_SYMLINK
} file_type_t;
/*
* For every file found in the local or remote system, we have a file entry
* that contains information about the file on both systems. For relation
* files, there is also a page map that marks pages in the file that were
* changed in the target after the last common checkpoint.
*
* When gathering information, these are kept in a hash table, private to
* filemap.c. decide_file_actions() fills in the 'action' field, sorts all
* the entries, and returns them in an array, ready for executing the actions.
*/
typedef struct file_entry_t
{
uint32 status; /* hash status */
const char *path;
bool isrelfile; /* is it a relation data file? */
/*
* Status of the file in the target.
*/
bool target_exists;
file_type_t target_type;
size_t target_size; /* for a regular file */
char *target_link_target; /* for a symlink */
/*
* Pages that were modified in the target and need to be replaced from the
* source.
*/
datapagemap_t target_pages_to_overwrite;
/*
* Status of the file in the source.
*/
bool source_exists;
file_type_t source_type;
size_t source_size;
char *source_link_target; /* for a symlink */
/*
* What will we do to the file?
*/
file_action_t action;
} file_entry_t;
/*
* This contains the final decisions on what to do with each file.
* 'entries' array contains an entry for each file, sorted in the order
* that their actions should executed.
*/
typedef struct filemap_t
{
/* Summary information, filled by calculate_totals() */
uint64 total_size; /* total size of the source cluster */
uint64 fetch_size; /* number of bytes that needs to be copied */
int nentries; /* size of 'entries' array */
file_entry_t *entries[FLEXIBLE_ARRAY_MEMBER];
} filemap_t;
/* Functions for populating the filemap */
extern void filehash_init(void);
extern void process_source_file(const char *path, file_type_t type,
size_t size, const char *link_target);
extern void process_target_file(const char *path, file_type_t type,
size_t size, const char *link_target);
extern void process_target_wal_block_change(ForkNumber forknum,
RelFileNode rnode,
BlockNumber blkno);
extern filemap_t *decide_file_actions(void);
extern void calculate_totals(filemap_t *filemap);
extern void print_filemap(filemap_t *filemap);
#endif /* FILEMAP_H */
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