/*****************************************************************************

Copyright (c) 2013, 2016, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2018, MariaDB Corporation.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
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This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA

*****************************************************************************/

/**************************************************//**
@file include/fsp0file.h
Tablespace data file implementation.

Created 2013-7-26 by Kevin Lewis
*******************************************************/

#ifndef fsp0file_h
#define fsp0file_h

#include "mem0mem.h"
#include "os0file.h"
#include "fil0fil.h"

/** Types of raw partitions in innodb_data_file_path */
enum device_t {
	SRV_NOT_RAW = 0,	/*!< Not a raw partition */
	SRV_NEW_RAW,		/*!< A 'newraw' partition, only to be
				initialized */
	SRV_OLD_RAW		/*!< An initialized raw partition */
};

/** Data file control information. */
class Datafile {

	friend class Tablespace;
	friend class SysTablespace;

public:

	Datafile()
		:
		m_name(),
		m_filepath(),
		m_filename(),
		m_handle(),
		m_open_flags(OS_FILE_OPEN),
		m_size(),
		m_order(),
		m_type(SRV_NOT_RAW),
		m_space_id(ULINT_UNDEFINED),
		m_flags(),
		m_exists(),
		m_is_valid(),
		m_first_page(),
		m_last_os_error(),
		m_file_info()
	{
		/* No op */
	}

	Datafile(const char* name, ulint flags, ulint size, ulint order)
		:
		m_name(mem_strdup(name)),
		m_filepath(),
		m_filename(),
		m_handle(),
		m_open_flags(OS_FILE_OPEN),
		m_size(size),
		m_order(order),
		m_type(SRV_NOT_RAW),
		m_space_id(ULINT_UNDEFINED),
		m_flags(flags),
		m_exists(),
		m_is_valid(),
		m_first_page(),
		m_last_os_error(),
		m_file_info()
	{
		ut_ad(m_name != NULL);
		/* No op */
	}

	Datafile(const Datafile& file)
		:
		m_handle(file.m_handle),
		m_open_flags(file.m_open_flags),
		m_size(file.m_size),
		m_order(file.m_order),
		m_type(file.m_type),
		m_space_id(file.m_space_id),
		m_flags(file.m_flags),
		m_exists(file.m_exists),
		m_is_valid(file.m_is_valid),
		m_first_page(),
		m_last_os_error(),
		m_file_info()
	{
		m_name = mem_strdup(file.m_name);
		ut_ad(m_name != NULL);

		if (file.m_filepath != NULL) {
			m_filepath = mem_strdup(file.m_filepath);
			ut_a(m_filepath != NULL);
			set_filename();
		} else {
			m_filepath = NULL;
			m_filename = NULL;
		}
	}

	virtual ~Datafile()
	{
		shutdown();
	}

	Datafile& operator=(const Datafile& file)
	{
		ut_a(this != &file);

		ut_ad(m_name == NULL);
		m_name = mem_strdup(file.m_name);
		ut_a(m_name != NULL);

		m_size = file.m_size;
		m_order = file.m_order;
		m_type = file.m_type;

		ut_a(m_handle == OS_FILE_CLOSED);
		m_handle = file.m_handle;

		m_exists = file.m_exists;
		m_is_valid = file.m_is_valid;
		m_open_flags = file.m_open_flags;
		m_space_id = file.m_space_id;
		m_flags = file.m_flags;
		m_last_os_error = 0;

		if (m_filepath != NULL) {
			ut_free(m_filepath);
			m_filepath = NULL;
			m_filename = NULL;
		}

		if (file.m_filepath != NULL) {
			m_filepath = mem_strdup(file.m_filepath);
			ut_a(m_filepath != NULL);
			set_filename();
		}

		/* Do not make a copy of the first page,
		it should be reread if needed */
		m_first_page = NULL;

		return(*this);
	}

	/** Initialize the name and flags of this datafile.
	@param[in]	name	tablespace name, will be copied
	@param[in]	flags	tablespace flags */
	void init(const char* name, ulint flags);

	/** Release the resources. */
	virtual void shutdown();

	/** Open a data file in read-only mode to check if it exists
	so that it can be validated.
	@param[in]	strict	whether to issue error messages
	@return DB_SUCCESS or error code */
	virtual dberr_t open_read_only(bool strict);

	/** Open a data file in read-write mode during start-up so that
	doublewrite pages can be restored and then it can be validated.
	@param[in]	read_only_mode	if true, then readonly mode checks
					are enforced.
	@return DB_SUCCESS or error code */
	virtual dberr_t open_read_write(bool read_only_mode)
		MY_ATTRIBUTE((warn_unused_result));

	/** Initialize OS specific file info. */
	void init_file_info();

	/** Close a data file.
	@return DB_SUCCESS or error code */
	dberr_t close();

	/** Make a full filepath from a directory path and a filename.
	Prepend the dirpath to filename using the extension given.
	If dirpath is NULL, prepend the default datadir to filepath.
	Store the result in m_filepath.
	@param[in]	dirpath		directory path
	@param[in]	filename	filename or filepath
	@param[in]	ext		filename extension */
	void make_filepath(
		const char*	dirpath,
		const char*	filename,
		ib_extention	ext);

	/** Set the filepath by duplicating the filepath sent in */
	void set_filepath(const char* filepath);

	/** Allocate and set the datafile or tablespace name in m_name.
	If a name is provided, use it; else extract a file-per-table
	tablespace name from m_filepath. The value of m_name
	will be freed in the destructor.
	@param[in]	name	Tablespace Name if known, NULL if not */
	void set_name(const char*	name);

	/** Validates the datafile and checks that it conforms with
	the expected space ID and flags.  The file should exist and be
	successfully opened in order for this function to validate it.
	@param[in]	space_id	The expected tablespace ID.
	@param[in]	flags		The expected tablespace flags.
	@retval DB_SUCCESS if tablespace is valid, DB_ERROR if not.
	m_is_valid is also set true on success, else false. */
	dberr_t validate_to_dd(ulint space_id, ulint flags)
		MY_ATTRIBUTE((warn_unused_result));

	/** Validates this datafile for the purpose of recovery.
	The file should exist and be successfully opened. We initially
	open it in read-only mode because we just want to read the SpaceID.
	However, if the first page is corrupt and needs to be restored
	from the doublewrite buffer, we will reopen it in write mode and
	ry to restore that page.
	@retval DB_SUCCESS if tablespace is valid, DB_ERROR if not.
	m_is_valid is also set true on success, else false. */
	dberr_t validate_for_recovery()
		MY_ATTRIBUTE((warn_unused_result));

	/** Checks the consistency of the first page of a datafile when the
	tablespace is opened.  This occurs before the fil_space_t is created
	so the Space ID found here must not already be open.
	m_is_valid is set true on success, else false.
	@param[out]	flush_lsn	contents of FIL_PAGE_FILE_FLUSH_LSN
	@retval DB_SUCCESS on if the datafile is valid
	@retval DB_CORRUPTION if the datafile is not readable
	@retval DB_TABLESPACE_EXISTS if there is a duplicate space_id */
	dberr_t validate_first_page(lsn_t* flush_lsn)
		MY_ATTRIBUTE((warn_unused_result));

	/** Get Datafile::m_name.
	@return m_name */
	const char*	name()	const
	{
		return(m_name);
	}

	/** Get Datafile::m_filepath.
	@return m_filepath */
	const char*	filepath()	const
	{
		return(m_filepath);
	}

	/** Get Datafile::m_handle.
	@return m_handle */
	pfs_os_file_t	handle()	const
	{
		return(m_handle);
	}

	/** Get Datafile::m_order.
	@return m_order */
	ulint	order()	const
	{
		return(m_order);
	}

	/** Get Datafile::m_space_id.
	@return m_space_id */
	ulint	space_id()	const
	{
		return(m_space_id);
	}

	/** Get Datafile::m_flags.
	@return m_flags */
	ulint	flags()	const
	{
		return(m_flags);
	}

	/**
	@return true if m_handle is open, false if not */
	bool	is_open()	const
	{
		return(m_handle != OS_FILE_CLOSED);
	}

	/** Get Datafile::m_is_valid.
	@return m_is_valid */
	bool	is_valid()	const
	{
		return(m_is_valid);
	}

	/** Get the last OS error reported
	@return m_last_os_error */
	ulint	last_os_error()		const
	{
		return(m_last_os_error);
	}

	/** Check whether the file is empty.
	@return true if file is empty */
	bool	is_empty_file()		const
	{
#ifdef _WIN32
		os_offset_t	offset =
			(os_offset_t) m_file_info.nFileSizeLow
			| ((os_offset_t) m_file_info.nFileSizeHigh << 32);

		return (offset == 0);
#else
		return (m_file_info.st_size == 0);
#endif
	}

	/** Check if the file exist.
	@return true if file exists. */
	bool exists()	const { return m_exists; }

	/** Test if the filepath provided looks the same as this filepath
	by string comparison. If they are two different paths to the same
	file, same_as() will be used to show that after the files are opened.
	@param[in]	other	filepath to compare with
	@retval true if it is the same filename by char comparison
	@retval false if it looks different */
	bool same_filepath_as(const char* other) const;

	/** Test if another opened datafile is the same file as this object.
	@param[in]	other	Datafile to compare with
	@return true if it is the same file, else false */
	bool same_as(const Datafile&	other) const;

	/** Get access to the first data page.
	It is valid after open_read_only() succeeded.
	@return the first data page */
	const byte* get_first_page() const { return(m_first_page); }

private:
	/** Free the filepath buffer. */
	void free_filepath();

	/** Set the filename pointer to the start of the file name
	in the filepath. */
	void set_filename()
	{
		if (m_filepath == NULL) {
			return;
		}

		char* last_slash = strrchr(m_filepath, OS_PATH_SEPARATOR);

		m_filename = last_slash ? last_slash + 1 : m_filepath;
	}

	/** Create/open a data file.
	@param[in]	read_only_mode	if true, then readonly mode checks
					are enforced.
	@return DB_SUCCESS or error code */
	dberr_t open_or_create(bool read_only_mode)
		MY_ATTRIBUTE((warn_unused_result));

	/** Reads a few significant fields from the first page of the
	datafile, which must already be open.
	@param[in]	read_only_mode	if true, then readonly mode checks
					are enforced.
	@return DB_SUCCESS or DB_IO_ERROR if page cannot be read */
	dberr_t read_first_page(bool read_only_mode)
		MY_ATTRIBUTE((warn_unused_result));

	/** Free the first page from memory when it is no longer needed. */
	void free_first_page();

	/** Set the Datafile::m_open_flags.
	@param open_flags	The Open flags to set. */
	void set_open_flags(os_file_create_t	open_flags)
	{
		m_open_flags = open_flags;
	};

	/** Determine if this datafile is on a Raw Device
	@return true if it is a RAW device. */
	bool is_raw_device()
	{
		return(m_type != SRV_NOT_RAW);
	}

	/* DATA MEMBERS */

	/** Datafile name at the tablespace location.
	This is either the basename of the file if an absolute path
	was entered, or it is the relative path to the datadir or
	Tablespace::m_path. */
	char*			m_name;

protected:
	/** Physical file path with base name and extension */
	char*			m_filepath;

private:
	/** Determine the space id of the given file descriptor by reading
	a few pages from the beginning of the .ibd file.
	@return DB_SUCCESS if space id was successfully identified,
	else DB_ERROR. */
	dberr_t find_space_id();

	/** Restore the first page of the tablespace from
	the double write buffer.
	@return whether the operation failed */
	bool restore_from_doublewrite();

	/** Points into m_filepath to the file name with extension */
	char*			m_filename;

	/** Open file handle */
	pfs_os_file_t		m_handle;

	/** Flags to use for opening the data file */
	os_file_create_t	m_open_flags;

	/** size in megabytes or pages; converted from megabytes to
	pages in SysTablespace::normalize_size() */
	ulint			m_size;

	/** ordinal position of this datafile in the tablespace */
	ulint			m_order;

	/** The type of the data file */
	device_t		m_type;

	/** Tablespace ID. Contained in the datafile header.
	If this is a system tablespace, FSP_SPACE_ID is only valid
	in the first datafile. */
	ulint			m_space_id;

	/** Tablespace flags. Contained in the datafile header.
	If this is a system tablespace, FSP_SPACE_FLAGS are only valid
	in the first datafile. */
	ulint			m_flags;

	/** true if file already existed on startup */
	bool			m_exists;

	/* true if the tablespace is valid */
	bool			m_is_valid;

	/** Aligned buffer to hold first page */
	byte*			m_first_page;

protected:
	/** Last OS error received so it can be reported if needed. */
	ulint			m_last_os_error;

public:
	/** Use the following to determine the uniqueness of this datafile. */
#ifdef _WIN32
	/* Use fields dwVolumeSerialNumber, nFileIndexLow, nFileIndexHigh. */
	BY_HANDLE_FILE_INFORMATION	m_file_info;
#else
	/* Use field st_ino. */
	struct stat			m_file_info;
#endif	/* WIN32 */
};


/** Data file control information. */
class RemoteDatafile : public Datafile
{
private:
	/** Link filename (full path) */
	char*	m_link_filepath;

public:

	RemoteDatafile()
		:
		m_link_filepath()
	{
		/* No op - base constructor is called. */
	}

	RemoteDatafile(const char*, ulint, ulint)
		:
		m_link_filepath()
	{
		/* No op - base constructor is called. */
	}

	~RemoteDatafile() override
	{
		shutdown();
	}

	/** Release the resources. */
	void shutdown() override;

	/** Get the link filepath.
	@return m_link_filepath */
	const char*	link_filepath()	const
	{
		return(m_link_filepath);
	}

	/** Create a link filename based on the contents of m_name,
	open that file, and read the contents into m_filepath.
	@retval DB_SUCCESS if remote linked tablespace file is opened and read.
	@retval DB_CANNOT_OPEN_FILE if the link file does not exist. */
	dberr_t open_link_file();

	/** Delete an InnoDB Symbolic Link (ISL) file. */
	void delete_link_file(void);

	/** Open a handle to the file linked to in an InnoDB Symbolic Link file
	in read-only mode so that it can be validated.
	@param[in]	strict	whether to issue error messages
	@return DB_SUCCESS or error code */
	dberr_t open_read_only(bool strict) override;

	/** Opens a handle to the file linked to in an InnoDB Symbolic Link
	file in read-write mode so that it can be restored from doublewrite
	and validated.
	@param[in]	read_only_mode	If true, then readonly mode checks
					are enforced.
	@return DB_SUCCESS or error code */
	dberr_t open_read_write(bool read_only_mode) override
		MY_ATTRIBUTE((warn_unused_result));

	/******************************************************************
	Global Static Functions;  Cannot refer to data members.
	******************************************************************/

	/** Creates a new InnoDB Symbolic Link (ISL) file.  It is always
	created under the 'datadir' of MySQL. The datadir is the directory
	of a running mysqld program. We can refer to it by simply using
	the path ".".
	@param[in]	name		tablespace name
	@param[in]	filepath	remote filepath of tablespace datafile
	@return DB_SUCCESS or error code */
	static dberr_t create_link_file(
		const char*	name,
		const char*	filepath);

	/** Delete an InnoDB Symbolic Link (ISL) file by name.
	@param[in]	name	tablespace name */
	static void delete_link_file(const char* name);

	/** Read an InnoDB Symbolic Link (ISL) file by name.
	It is always created under the datadir of MySQL.
	For file-per-table tablespaces, the isl file is expected to be
	in a 'database' directory and called 'tablename.isl'.
	The caller must free the memory returned if it is not null.
	@param[in]	link_filepath	filepath of the ISL file
	@return Filepath of the IBD file read from the ISL file */
	static char* read_link_file(
		const char*	link_filepath);
};
#endif /* fsp0file_h */