mtcore::io::SyncFileSystem Struct Reference

Synchronous File System interface for handling I/O calls This is encapsulated as a struct of file pointers so we can do deterministic testing This allows us to also dynamically swap things out for different file systems, or even do remote "file systems" where we're reading and writing to an object store (e.g. More...

#include <file_sys.hpp>

Collaboration diagram for mtcore::io::SyncFileSystem:

Public Member Functions
Result< void, FileError >	write_file_safe (Allocator &tmpAlloc, const char *path, Slice< const u8 > data, Prng &prng) const
	Overwrites a file's contents by first creating a temporary file and then doing a rename Will sync file to disk If there is a system failure, the worst case is that a corrupted temporary file exists on the disk.
Result< void, FileError >	write_file_direct (const char *path, Slice< const u8 > data) const
	Overwrites a file's contents directly Will sync file to disk.
Result< Slice< u8 >, FileError >	read_file_into (const char *path, Slice< u8 > out) const
	Reads a file into a static buffer.
Result< Slice< char >, FileError >	read_file_str_into (const char *path, const Slice< char > out) const
	Reads a file into a static buffer of chars (for text data).
Result< void, FileError >	read_file (Allocator &alloc, const char *path, Slice< u8 > &out) const
	Reads a file into a dynamically allocated buffer and then sets out to point to that buffer.
Result< void, FileError >	read_file_str (Allocator &alloc, const char *path, Slice< char > &out) const
	Reads a file into a dynamically allocated buffer and then sets out to point to that buffer The buffer will be a buffer of chars for text data On success, returns 0, otherwise returns -1 NOTE: the caller MUST free the allocated memory by calling a_free(<allocator>, out.head)
Result< Slice< u8 >, FileError >	read_chunk_into (FILE *file, const Slice< u8 > out) const
	Reads a chunk of characters from a file handle (without closing) into a buffer On success, returns a buffer that's a substring into the buffer On failure, returns a buffer that has a start of NULL and length of 0.
Result< Slice< char >, FileError >	read_chunk_str_into (FILE *file, const Slice< char > out) const
	Reads a chunk of characters from a file handle (without closing) into a buffer Uses a buffer of chars for text data On success, returns a buffer that's a substring into the buffer On failure, returns a buffer that has a start of NULL and length of 0.
Result< void, FileError >	write_chunk (FILE *file, const Slice< const u8 > buff) const
	Writes a chunk of data into a file handle (without closing) from a buffer If the entire buffer could not be written, will return -1.
Result< void, FileError >	write_chunk_str (FILE *file, const Slice< const char > buff) const
	Writes a chunk of data into a file handle (without closing) from a buffer of chars (text) If the entire buffer could not be written, will return -1.
Result< FILE *, FileError >	open (const char *path, const char *mode) const
	Opens a file handle On failure, returns NULL.
Result< void, FileError >	sync (FILE *file) const
	Syncs a file to disk.
Result< void, FileError >	close (FILE *file) const
	Closes a file handle.
Result< void, FileError >	rename (const char *oldPath, const char *newPath) const
	Renames a file.
Result< void, FileError >	remove (const char *path) const
	Removes a file.

Public Attributes
const SyncFileSystemVTable *	vtable = nullptr
	Underlying vtable for file operations.
void *	state = nullptr

Detailed Description

Synchronous File System interface for handling I/O calls This is encapsulated as a struct of file pointers so we can do deterministic testing This allows us to also dynamically swap things out for different file systems, or even do remote "file systems" where we're reading and writing to an object store (e.g.

S3, file share, SFTP, etc) Also, we could extend it to have more locks behind the scenes or whatever Note: This does NOT perform asynchronous I/O, only synchronous I/O

Only need to define SyncFileSystemVTable to create a simulated file system, or to change underlying system calls

Definition at line 138 of file file_sys.hpp.

Member Function Documentation

close()

Result< void, FileError > mtcore::io::SyncFileSystem::close ( FILE * file ) const

nodiscard

Closes a file handle.

Parameters

file	File pointer to close

Returns

On failure returns error

open()

Result< FILE *, FileError > mtcore::io::SyncFileSystem::open ( const char * path, const char * mode ) const

nodiscard

Opens a file handle On failure, returns NULL.

Parameters

path	File path to open
mode	File mode to use (e.g. "rb")

Returns

File pointer on success, nullptr on failure

read_chunk_into()

Result< Slice< u8 >, FileError > mtcore::io::SyncFileSystem::read_chunk_into ( FILE * file, const Slice< u8 > out ) const

nodiscard

Reads a chunk of characters from a file handle (without closing) into a buffer On success, returns a buffer that's a substring into the buffer On failure, returns a buffer that has a start of NULL and length of 0.

Parameters

file	File pointer to read from
out	Buffer to read into. Will read at most out.len characters

Returns

Sub-Slice of characters read. Empty if at end or unable to read

read_chunk_str_into()

Result< Slice< char >, FileError > mtcore::io::SyncFileSystem::read_chunk_str_into ( FILE * file, const Slice< char > out ) const

nodiscard

Reads a chunk of characters from a file handle (without closing) into a buffer Uses a buffer of chars for text data On success, returns a buffer that's a substring into the buffer On failure, returns a buffer that has a start of NULL and length of 0.

Parameters

file	File pointer to read from
out	Buffer to read into. Will read at most out.len characters

Returns

Sub-Slice of characters read. Empty if at end or unable to read

read_file()

Result< void, FileError > mtcore::io::SyncFileSystem::read_file ( Allocator & alloc, const char * path, Slice< u8 > & out ) const

nodiscard

Reads a file into a dynamically allocated buffer and then sets out to point to that buffer.

On failure returns error NOTE: the caller MUST free the allocated memory by calling a_free(<allocator>, out.head)

Parameters

alloc	Allocator to use to allocate buffer for file contents
path	File path to read from
out	Reference to Slice that will hold the allocated file contents

Returns

On failure returns error

read_file_into()

Result< Slice< u8 >, FileError > mtcore::io::SyncFileSystem::read_file_into ( const char * path, Slice< u8 > out ) const

nodiscard

Reads a file into a static buffer.

On success, will return a buffer that's a subset of the original buffer with written contents On failure, will return a buffer that's set to NULL with length 0

Parameters

path	File path to read from
out	Output buffer to write to. Will not allocate

Returns

Sub-Slice containing file contents (in case full Slice was too large) or an error

read_file_str()

Result< void, FileError > mtcore::io::SyncFileSystem::read_file_str ( Allocator & alloc, const char * path, Slice< char > & out ) const

nodiscard

Reads a file into a dynamically allocated buffer and then sets out to point to that buffer The buffer will be a buffer of chars for text data On success, returns 0, otherwise returns -1 NOTE: the caller MUST free the allocated memory by calling a_free(<allocator>, out.head)

Parameters

alloc	Allocator to use to allocate buffer for file contents
path	File path to read from
out	Reference to Slice that will hold the allocated file contents

Returns

On failure returns error

read_file_str_into()

Result< Slice< char >, FileError > mtcore::io::SyncFileSystem::read_file_str_into ( const char * path, const Slice< char > out ) const

nodiscard

Reads a file into a static buffer of chars (for text data).

On success, will return a buffer that's a subset of the original buffer with written contents On failure, will return a buffer that's set to NULL with length 0

Parameters

path	File path to read from
out	Output buffer to write to. Will not allocate

Returns

Sub-Slice containing file contents (in case full Slice was too large) or an error

remove()

Result< void, FileError > mtcore::io::SyncFileSystem::remove ( const char * path ) const

nodiscard

Removes a file.

Parameters

path	Target file name

Returns

On failure returns error

rename()

Result< void, FileError > mtcore::io::SyncFileSystem::rename ( const char * oldPath, const char * newPath ) const

nodiscard

Renames a file.

Parameters

oldPath	Current file name
newPath	Target file name

Returns

On failure returns error

sync()

Result< void, FileError > mtcore::io::SyncFileSystem::sync ( FILE * file ) const

nodiscard

Syncs a file to disk.

Parameters

file	File pointer to sync

Returns

On failure returns error

write_chunk()

Result< void, FileError > mtcore::io::SyncFileSystem::write_chunk ( FILE * file, const Slice< const u8 > buff ) const

nodiscard

Writes a chunk of data into a file handle (without closing) from a buffer If the entire buffer could not be written, will return -1.

Parameters

file	File pointer to write to
buff	Data to write to file

Returns

On failure returns error

write_chunk_str()

Result< void, FileError > mtcore::io::SyncFileSystem::write_chunk_str ( FILE * file, const Slice< const char > buff ) const

nodiscard

Writes a chunk of data into a file handle (without closing) from a buffer of chars (text) If the entire buffer could not be written, will return -1.

Parameters

file	File pointer to write to
buff	Data to write to file

Returns

On failure returns error

write_file_direct()

Result< void, FileError > mtcore::io::SyncFileSystem::write_file_direct	(	const char *	path,
		Slice< const u8 >	data ) const

Overwrites a file's contents directly Will sync file to disk.

Parameters

path	Final destination path
data	Data two write to disk

Returns

success or error code otherwise

write_file_safe()

Result< void, FileError > mtcore::io::SyncFileSystem::write_file_safe	(	Allocator &	tmpAlloc,
		const char *	path,
		Slice< const u8 >	data,
		Prng &	prng ) const

Overwrites a file's contents by first creating a temporary file and then doing a rename Will sync file to disk If there is a system failure, the worst case is that a corrupted temporary file exists on the disk.

Parameters

tmpAlloc	Allocator for temporary, internal allocations (allocates temporary file name)
path	Final destination path
data	Data two write to disk
prng	PRNG to use to create temporary file name

Returns

success or error code otherwise

Member Data Documentation

state

void* mtcore::io::SyncFileSystem::state = nullptr

Definition at line 144 of file file_sys.hpp.

vtable

const SyncFileSystemVTable* mtcore::io::SyncFileSystem::vtable = nullptr

Underlying vtable for file operations.

Definition at line 143 of file file_sys.hpp.

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The documentation for this struct was generated from the following file:

• file_sys.hpp