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Share Oar path type with file system
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This commit is contained in:
kayomn 2022-10-19 14:16:05 +01:00
parent 174b16199e
commit 1a28dc2404
3 changed files with 293 additions and 311 deletions
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2
src/engine/main.zig
View File

@ -15,7 +15,7 @@ fn run(app: *sys.AppContext, graphics: *sys.GraphicsContext) anyerror!void {
defer _ = gpa.deinit();
{
var file_access = try (try app.data().joinedPath(&.{"ona.lua"})).open(.readonly);
var file_access = try app.data().open(try sys.Path.joined(&.{"ona.lua"}), .readonly);
defer file_access.close();

537
src/engine/sys.zig
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@ -274,305 +274,160 @@ pub const FileSystem = union(enum) {
archive: Archive,
///
/// Platform-agnostic mechanism for referencing files and directories on a [FileSystem].
/// With files typically being backed by a block device, they can produce a variety of
/// errors - from physical to virtual errors - these are all encapsulated by the API as
/// general [OpenError.FileNotFound] errors.
///
pub const Path = struct {
file_system: *FileSystem,
path: oar.Path,
/// When a given [FileSystem] does not support a specified [OpenMode],
/// [OpenError.ModeUnsupported] is used to inform the consuming code that another [OpenMode]
/// should be tried or, if no mode other is suitable, that the resource is effectively
/// unavailable.
///
/// If the number of known [FileAccess] handles has been exhausted, [OpenError.OutOfFiles]
/// is used to communicate this.
///
pub const OpenError = error {
FileNotFound,
ModeUnsupported,
OutOfFiles,
};
///
/// With files typically being backed by a block device, they can produce a variety of
/// errors - from physical to virtual errors - these are all encapsulated by the API as
/// general [OpenError.FileNotFound] errors.
///
/// When a given [FileSystem] does not support a specified [OpenMode],
/// [OpenError.ModeUnsupported] is used to inform the consuming code that another [OpenMode]
/// should be tried or, if no mode other is suitable, that the resource is effectively
/// unavailable.
///
/// If the number of known [FileAccess] handles has been exhausted, [OpenError.OutOfFiles]
/// is used to communicate this.
///
pub const OpenError = error {
FileNotFound,
ModeUnsupported,
OutOfFiles,
};
///
/// [OpenMode.readonly] indicates that an existing file is opened in a read-only state,
/// disallowing write access.
///
/// [OpenMode.overwrite] indicates that an empty file has been created or an existing file has
/// been completely overwritten into.
///
/// [OpenMode.append] indicates that an existing file that has been opened for reading from and
/// writing to on the end of existing data.
///
pub const OpenMode = enum {
readonly,
overwrite,
append,
};
///
/// [OpenMode.readonly] indicates that an existing file is opened in a read-only state,
/// disallowing write access.
///
/// [OpenMode.overwrite] indicates that an empty file has been created or an existing file
/// has been completely overwritten into.
///
/// [OpenMode.append] indicates that an existing file that has been opened for reading from
/// and writing to on the end of existing data.
///
pub const OpenMode = enum {
readonly,
overwrite,
append,
};
///
/// Attempts to open the file identified by `path` with `mode` as the mode for opening the file.
///
/// Returns a [FileAccess] reference that provides access to the file referenced by `path`or a
/// [OpenError] if it failed.
///
pub fn open(file_system: *FileSystem, path: Path, mode: OpenMode) OpenError!ona.io.FileAccess {
switch (file_system.*) {
.archive => |*archive| {
if (mode != .readonly) return error.ModeUnsupported;
///
/// Returns `true` if the length of `path` is empty, otherwise `false`.
///
pub fn isEmpty(path: Path) bool {
return (path.length == 0);
}
///
/// Returns `true` if `this` is equal to `that`, otherwise `false`.
///
pub fn equals(this: Path, that: Path) bool {
return (this.file_system == that.file_system) and
std.mem.eql(u8, this.buffer[0 .. this.length], that.buffer[0 .. that.length]);
}
///
/// The maximum possible byte-length of a [Path].
///
/// Note that paths are encoded using UTF-8, meaning that a character may be bigger than one
/// byte. Because of this, it is not safe to asume that a path may hold [max] individual
/// characters.
///
pub const max = 255;
///
/// Attempts to open the file identified by `path` with `mode` as the mode for opening the
/// file.
///
/// Returns a [FileAccess] reference that provides access to the file referenced by `path`
/// or a [OpenError] if it failed.
///
pub fn open(path: Path, mode: OpenMode) OpenError!ona.io.FileAccess {
switch (path.file_system.*) {
.archive => |*archive| {
if (mode != .readonly) return error.ModeUnsupported;
const FileAccess = ona.io.FileAccess;
for (archive.entry_table) |*entry| if (entry.owner == null) {
const Implementation = struct {
fn archiveEntryCast(context: *anyopaque) *Archive.Entry {
return @ptrCast(*Archive.Entry, @alignCast(
@alignOf(Archive.Entry), context));
}
fn close(context: *anyopaque) void {
archiveEntryCast(context).owner = null;
}
fn queryCursor(context: *anyopaque) FileAccess.Error!u64 {
const archive_entry = archiveEntryCast(context);
if (archive_entry.owner == null) return error.FileInaccessible;
return archive_entry.cursor;
}
fn queryLength(context: *anyopaque) FileAccess.Error!u64 {
const archive_entry = archiveEntryCast(context);
if (archive_entry.owner == null) return error.FileInaccessible;
return archive_entry.header.file_size;
}
fn read(context: *anyopaque, buffer: []u8) FileAccess.Error!usize {
const archive_entry = archiveEntryCast(context);
const file_access = archive_entry.owner orelse
return error.FileInaccessible;
if (archive_entry.cursor >= archive_entry.header.file_size)
return error.FileInaccessible;
try file_access.seek(archive_entry.header.absolute_offset);
return file_access.read(buffer[0 .. std.math.min(
buffer.len, archive_entry.header.file_size)]);
}
fn seek(context: *anyopaque, cursor: usize) FileAccess.Error!void {
const archive_entry = archiveEntryCast(context);
if (archive_entry.owner == null) return error.FileInaccessible;
archive_entry.cursor = cursor;
}
fn seekToEnd(context: *anyopaque) FileAccess.Error!void {
const archive_entry = archiveEntryCast(context);
if (archive_entry.owner == null) return error.FileInaccessible;
archive_entry.cursor = archive_entry.header.file_size;
}
fn skip(context: *anyopaque, offset: i64) FileAccess.Error!void {
const math = std.math;
const archive_entry = archiveEntryCast(context);
if (archive_entry.owner == null) return error.FileInaccessible;
if (offset < 0) {
archive_entry.cursor = math.max(0,
archive_entry.cursor - math.absCast(offset));
} else {
archive_entry.cursor += @intCast(u64, offset);
}
}
};
if (archive.index_cache.lookup(path.path)) |index| {
archive.file_access.seek(index) catch return error.FileNotFound;
entry.* = .{
.owner = &archive.file_access,
.cursor = 0,
.header = (oar.Entry.next(archive.file_access) catch return error.FileNotFound) orelse {
// Remove cannot fail if lookup succeeded.
std.debug.assert(archive.index_cache.remove(path.path) != null);
return error.FileNotFound;
},
};
} else {
while (oar.Entry.next(archive.file_access) catch return error.FileNotFound) |entry_header| {
if (entry.header.path.equals(path.path))
entry.* = .{
.owner = &archive.file_access,
.cursor = 0,
.header = entry_header,
};
}
return error.FileNotFound;
}
return FileAccess{
.context = entry,
.implementation = &.{
.close = Implementation.close,
.queryCursor = Implementation.queryCursor,
.queryLength = Implementation.queryLength,
.read = Implementation.read,
.seek = Implementation.seek,
.seekToEnd = Implementation.seekToEnd,
.skip = Implementation.skip,
},
};
};
return error.OutOfFiles;
},
.native => |native| {
if (native.len == 0) return error.FileNotFound;
var path_buffer = std.mem.zeroes([4096]u8);
const seperator_length = @boolToInt(native[native.len - 1] != seperator);
if ((native.len + seperator_length + path.path.length) >=
path_buffer.len) return error.FileNotFound;
std.mem.copy(u8, path_buffer[0 ..], native);
if (seperator_length != 0) path_buffer[native.len] = seperator;
std.mem.copy(u8, path_buffer[native.len .. path_buffer.
len], path.path.buffer[0 .. path.path.length]);
ext.SDL_ClearError();
const FileAccess = ona.io.FileAccess;
const FileAccess = ona.io.FileAccess;
for (archive.entry_table) |*entry| if (entry.owner == null) {
const Implementation = struct {
fn rwOpsCast(context: *anyopaque) *ext.SDL_RWops {
return @ptrCast(*ext.SDL_RWops, @alignCast(
@alignOf(ext.SDL_RWops), context));
fn archiveEntryCast(context: *anyopaque) *Archive.Entry {
return @ptrCast(*Archive.Entry, @alignCast(
@alignOf(Archive.Entry), context));
}
fn close(context: *anyopaque) void {
ext.SDL_ClearError();
if (ext.SDL_RWclose(rwOpsCast(context)) != 0)
ext.SDL_LogWarn(ext.SDL_LOG_CATEGORY_APPLICATION, ext.SDL_GetError());
archiveEntryCast(context).owner = null;
}
fn queryCursor(context: *anyopaque) FileAccess.Error!u64 {
ext.SDL_ClearError();
const archive_entry = archiveEntryCast(context);
const sought = ext.SDL_RWtell(rwOpsCast(context));
if (archive_entry.owner == null) return error.FileInaccessible;
if (sought < 0) return error.FileInaccessible;
return @intCast(u64, sought);
return archive_entry.cursor;
}
fn queryLength(context: *anyopaque) FileAccess.Error!u64 {
ext.SDL_ClearError();
const archive_entry = archiveEntryCast(context);
const sought = ext.SDL_RWsize(rwOpsCast(context));
if (archive_entry.owner == null) return error.FileInaccessible;
if (sought < 0) return error.FileInaccessible;
return @intCast(u64, sought);
return archive_entry.header.file_size;
}
fn read(context: *anyopaque, buffer: []u8) FileAccess.Error!usize {
ext.SDL_ClearError();
const archive_entry = archiveEntryCast(context);
const buffer_read = ext.SDL_RWread(rwOpsCast(
context), buffer.ptr, @sizeOf(u8), buffer.len);
if ((buffer_read == 0) and (ext.SDL_GetError() != null))
const file_access = archive_entry.owner orelse
return error.FileInaccessible;
return buffer_read;
if (archive_entry.cursor >= archive_entry.header.file_size)
return error.FileInaccessible;
try file_access.seek(archive_entry.header.absolute_offset);
return file_access.read(buffer[0 .. std.math.min(
buffer.len, archive_entry.header.file_size)]);
}
fn seek(context: *anyopaque, cursor: usize) FileAccess.Error!void {
var to_seek = cursor;
const archive_entry = archiveEntryCast(context);
while (to_seek != 0) {
const math = std.math;
const sought = math.min(to_seek, math.maxInt(i64));
if (archive_entry.owner == null) return error.FileInaccessible;
ext.SDL_ClearError();
if (ext.SDL_RWseek(rwOpsCast(context), @intCast(i64, sought),
ext.RW_SEEK_CUR) < 0) return error.FileInaccessible;
to_seek -= sought;
}
archive_entry.cursor = cursor;
}
fn seekToEnd(context: *anyopaque) FileAccess.Error!void {
ext.SDL_ClearError();
const archive_entry = archiveEntryCast(context);
if (ext.SDL_RWseek(rwOpsCast(context), 0, ext.RW_SEEK_END) < 0)
return error.FileInaccessible;
if (archive_entry.owner == null) return error.FileInaccessible;
archive_entry.cursor = archive_entry.header.file_size;
}
fn skip(context: *anyopaque, offset: i64) FileAccess.Error!void {
ext.SDL_ClearError();
const math = std.math;
const archive_entry = archiveEntryCast(context);
if (ext.SDL_RWseek(rwOpsCast(context), offset, ext.RW_SEEK_SET) < 0)
return error.FileInaccessible;
if (archive_entry.owner == null) return error.FileInaccessible;
if (offset < 0) {
archive_entry.cursor = math.max(0,
archive_entry.cursor - math.absCast(offset));
} else {
archive_entry.cursor += @intCast(u64, offset);
}
}
};
const Header = oar.Entry;
if (archive.index_cache.lookup(path)) |index| {
archive.file_access.seek(index) catch return error.FileNotFound;
entry.* = .{
.owner = &archive.file_access,
.cursor = 0,
.header = (Header.next(archive.file_access) catch
return error.FileNotFound) orelse {
// Remove cannot fail if lookup succeeded.
std.debug.assert(archive.index_cache.remove(path) != null);
return error.FileNotFound;
},
};
} else {
while (Header.next(archive.file_access) catch
return error.FileNotFound) |entry_header| {
if (entry.header.path.equals(path)) entry.* = .{
.owner = &archive.file_access,
.cursor = 0,
.header = entry_header,
};
}
return error.FileNotFound;
}
return FileAccess{
.context = ext.SDL_RWFromFile(&path_buffer, switch (mode) {
.readonly => "rb",
.overwrite => "wb",
.append => "ab",
}) orelse return error.FileNotFound,
.context = entry,
.implementation = &.{
.close = Implementation.close,
@ -584,69 +439,126 @@ pub const FileSystem = union(enum) {
.skip = Implementation.skip,
},
};
},
}
}
pub const seperator = '/';
};
///
/// [PathError.TooLong] occurs when creating a path that is greater than the maximum size **in
/// bytes**.
///
pub const PathError = error {
TooLong,
};
///
/// Attempts to create a [Path] with `file_system` as the file-system root and the path
/// components in `sequences` as a fully qualified path from the root.
///
/// A [Path] value is returned containing the fully qualified path from the file-system root or
/// a [PathError] if it could not be created.
///
pub fn joinedPath(file_system: *FileSystem, sequences: []const []const u8) PathError!Path {
var path = Path{
.file_system = file_system,
.path = oar.Path.empty,
};
if (sequences.len != 0) {
const last_sequence_index = sequences.len - 1;
for (sequences) |sequence, index| if (sequence.len != 0) {
var components = ona.io.Spliterator(u8){
.source = sequence,
.delimiter = "/",
};
while (components.next()) |component| if (component.len != 0) {
for (component) |byte| {
if (path.path.length == Path.max) return error.TooLong;
return error.OutOfFiles;
},
path.path.buffer[path.path.length] = byte;
path.path.length += 1;
.native => |native| {
if (native.len == 0) return error.FileNotFound;
var path_buffer = std.mem.zeroes([4096]u8);
const seperator_length = @boolToInt(native[native.len - 1] != oar.Path.seperator);
if ((native.len + seperator_length + path.length) >=
path_buffer.len) return error.FileNotFound;
std.mem.copy(u8, path_buffer[0 ..], native);
if (seperator_length != 0) path_buffer[native.len] = oar.Path.seperator;
std.mem.copy(u8, path_buffer[native.len .. path_buffer.
len], path.buffer[0 .. path.length]);
const FileAccess = ona.io.FileAccess;
const Implementation = struct {
fn rwOpsCast(context: *anyopaque) *ext.SDL_RWops {
return @ptrCast(*ext.SDL_RWops, @alignCast(
@alignOf(ext.SDL_RWops), context));
}
if (components.hasNext()) {
if (path.path.length == Path.max) return error.TooLong;
fn close(context: *anyopaque) void {
ext.SDL_ClearError();
path.path.buffer[path.path.length] = '/';
path.path.length += 1;
if (ext.SDL_RWclose(rwOpsCast(context)) != 0)
ext.SDL_LogWarn(ext.SDL_LOG_CATEGORY_APPLICATION, ext.SDL_GetError());
}
fn queryCursor(context: *anyopaque) FileAccess.Error!u64 {
ext.SDL_ClearError();
const sought = ext.SDL_RWtell(rwOpsCast(context));
if (sought < 0) return error.FileInaccessible;
return @intCast(u64, sought);
}
fn queryLength(context: *anyopaque) FileAccess.Error!u64 {
ext.SDL_ClearError();
const sought = ext.SDL_RWsize(rwOpsCast(context));
if (sought < 0) return error.FileInaccessible;
return @intCast(u64, sought);
}
fn read(context: *anyopaque, buffer: []u8) FileAccess.Error!usize {
ext.SDL_ClearError();
const buffer_read = ext.SDL_RWread(rwOpsCast(
context), buffer.ptr, @sizeOf(u8), buffer.len);
if ((buffer_read == 0) and (ext.SDL_GetError() != null))
return error.FileInaccessible;
return buffer_read;
}
fn seek(context: *anyopaque, cursor: usize) FileAccess.Error!void {
var to_seek = cursor;
while (to_seek != 0) {
const math = std.math;
const sought = math.min(to_seek, math.maxInt(i64));
ext.SDL_ClearError();
if (ext.SDL_RWseek(rwOpsCast(context), @intCast(i64, sought),
ext.RW_SEEK_CUR) < 0) return error.FileInaccessible;
to_seek -= sought;
}
}
fn seekToEnd(context: *anyopaque) FileAccess.Error!void {
ext.SDL_ClearError();
if (ext.SDL_RWseek(rwOpsCast(context), 0, ext.RW_SEEK_END) < 0)
return error.FileInaccessible;
}
fn skip(context: *anyopaque, offset: i64) FileAccess.Error!void {
ext.SDL_ClearError();
if (ext.SDL_RWseek(rwOpsCast(context), offset, ext.RW_SEEK_SET) < 0)
return error.FileInaccessible;
}
};
if (index < last_sequence_index) {
if (path.path.length == Path.max) return error.TooLong;
ext.SDL_ClearError();
path.path.buffer[path.path.length] = '/';
path.path.length += 1;
}
};
return FileAccess{
.context = ext.SDL_RWFromFile(&path_buffer, switch (mode) {
.readonly => "rb",
.overwrite => "wb",
.append => "ab",
}) orelse return error.FileNotFound,
.implementation = &.{
.close = Implementation.close,
.queryCursor = Implementation.queryCursor,
.queryLength = Implementation.queryLength,
.read = Implementation.read,
.seek = Implementation.seek,
.seekToEnd = Implementation.seekToEnd,
.skip = Implementation.skip,
},
};
},
}
return path;
}
};
@ -721,6 +633,11 @@ pub const Log = enum(u32) {
}
};
///
/// Path to a file on a [FileSystem].
///
pub const Path = oar.Path;
///
/// [RunError.InitFailure] occurs if a necessary resource fails to be acquired or allocated.
///
@ -774,7 +691,7 @@ pub fn runGraphics(comptime Error: anytype,
defer ext.SDL_DestroyRenderer(renderer);
var cwd_file_system = FileSystem{.native ="./"};
var data_access = try (try cwd_file_system.joinedPath(&.{"./data.oar"})).open(.readonly);
var data_access = try cwd_file_system.open(try Path.joined(&.{"./data.oar"}), .readonly);
defer data_access.close();

65
src/oar/main.zig
View File

@ -55,6 +55,14 @@ pub const Path = extern struct {
buffer: [255]u8,
length: u8,
///
/// [Error.TooLong] occurs when creating a path that is greater than the maximum path size **in
/// bytes**.
///
pub const Error = error {
TooLong,
};
///
/// An empty [Path] with a length of `0`.
///
@ -74,6 +82,63 @@ pub const Path = extern struct {
pub fn hash(path: Path) usize {
return ona.io.hashBytes(path.buffer[0 .. path.length]);
}
///
/// Attempts to create a [Path] with the path components in `sequences` as a fully qualified
/// path from root.
///
/// A [Path] value is returned containing the fully qualified path from the file-system root or
/// a [Error] if it could not be created.
///
pub fn joined(sequences: []const []const u8) Error!Path {
var path = empty;
if (sequences.len != 0) {
const last_sequence_index = sequences.len - 1;
for (sequences) |sequence, index| if (sequence.len != 0) {
var components = ona.io.Spliterator(u8){
.source = sequence,
.delimiter = "/",
};
while (components.next()) |component| if (component.len != 0) {
for (component) |byte| {
if (path.length == max) return error.TooLong;
path.buffer[path.length] = byte;
path.length += 1;
}
if (components.hasNext()) {
if (path.length == max) return error.TooLong;
path.buffer[path.length] = '/';
path.length += 1;
}
};
if (index < last_sequence_index) {
if (path.length == max) return error.TooLong;
path.buffer[path.length] = '/';
path.length += 1;
}
};
}
return path;
}
///
/// Maximum number of **bytes** in a [Path].
///
pub const max = 255;
///
/// Textual separator between components of a [Path].
///
pub const seperator = '/';
};
///