new primitives for reading/writing files

[lines.love.git] / nativefs.lua

--[[
Copyright 2020 megagrump@pm.me

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
]]--

local ffi, bit = require('ffi'), require('bit')
local C = ffi.C

local File = {
        getBuffer = function(self) return self._bufferMode, self._bufferSize end,
        getFilename = function(self) return self._name end,
        getMode = function(self) return self._mode end,
        isOpen = function(self) return self._mode ~= 'c' and self._handle ~= nil end,
}

local fopen, getcwd, chdir, unlink, mkdir, rmdir
local BUFFERMODE, MODEMAP
local ByteArray = ffi.typeof('unsigned char[?]')
local function _ptr(p) return p ~= nil and p or nil end -- NULL pointer to nil

function File:open(mode)
        if self._mode ~= 'c' then return false, "File " .. self._name .. " is already open" end
        if not MODEMAP[mode] then return false, "Invalid open mode for " .. self._name .. ": " .. mode end

        local handle = _ptr(fopen(self._name, MODEMAP[mode]))
        if not handle then return false, "Could not open " .. self._name .. " in mode " .. mode end

        self._handle, self._mode = ffi.gc(handle, C.fclose), mode
        self:setBuffer(self._bufferMode, self._bufferSize)

        return true
end

function File:close()
        if self._mode == 'c' then return false, "File is not open" end
        C.fclose(ffi.gc(self._handle, nil))
        self._handle, self._mode = nil, 'c'
        return true
end

function File:setBuffer(mode, size)
        local bufferMode = BUFFERMODE[mode]
        if not bufferMode then
                return false, "Invalid buffer mode " .. mode .. " (expected 'none', 'full', or 'line')"
        end

        if mode == 'none' then
                size = math.max(0, size or 0)
        else
                size = math.max(2, size or 2) -- Windows requires buffer to be at least 2 bytes
        end

        local success = self._mode == 'c' or C.setvbuf(self._handle, nil, bufferMode, size) == 0
        if not success then
                self._bufferMode, self._bufferSize = 'none', 0
                return false, "Could not set buffer mode"
        end

        self._bufferMode, self._bufferSize = mode, size
        return true
end

function File:getSize()
        -- NOTE: The correct way to do this would be a stat() call, which requires a
        -- lot more (system-specific) code. This is a shortcut that requires the file
        -- to be readable.
        local mustOpen = not self:isOpen()
        if mustOpen and not self:open('r') then return 0 end

        local pos = mustOpen and 0 or self:tell()
        C.fseek(self._handle, 0, 2)
        local size = self:tell()
        if mustOpen then
                self:close()
        else
                self:seek(pos)
        end
        return size
end

function File:read(containerOrBytes, bytes)
        if self._mode ~= 'r' then return nil, 0 end

        local container = bytes ~= nil and containerOrBytes or 'string'
        if container ~= 'string' and container ~= 'data' then
                error("Invalid container type: " .. container)
        end

        bytes = not bytes and containerOrBytes or 'all'
        bytes = bytes == 'all' and self:getSize() - self:tell() or math.min(self:getSize() - self:tell(), bytes)

        if bytes <= 0 then
                local data = container == 'string' and '' or love.data.newFileData('', self._name)
                return data, 0
        end

        local data = love.data.newByteData(bytes)
        local r = tonumber(C.fread(data:getFFIPointer(), 1, bytes, self._handle))

        local str = data:getString()
        data:release()
        data = container == 'data' and love.filesystem.newFileData(str, self._name) or str
        return data, r
end

local function lines(file, autoclose)
        local BUFFERSIZE = 4096
        local buffer, bufferPos = ByteArray(BUFFERSIZE), 0
        local bytesRead = tonumber(C.fread(buffer, 1, BUFFERSIZE, file._handle))

        local offset = file:tell()
        return function()
                file:seek(offset)

                local line = {}
                while bytesRead > 0 do
                        for i = bufferPos, bytesRead - 1 do
                                if buffer[i] == 10 then -- end of line
                                        bufferPos = i + 1
                                        return table.concat(line)
                                end

                                if buffer[i] ~= 13 then -- ignore CR
                                        table.insert(line, string.char(buffer[i]))
                                end
                        end

                        bytesRead = tonumber(C.fread(buffer, 1, BUFFERSIZE, file._handle))
                        offset, bufferPos = offset + bytesRead, 0
                end

                if not line[1] then
                        if autoclose then file:close() end
                        return nil
                end
                return table.concat(line)
        end
end

function File:lines()
        if self._mode ~= 'r' then error("File is not opened for reading") end
        return lines(self)
end

function File:write(data, size)
        if self._mode ~= 'w' and self._mode ~= 'a' then
                return false, "File " .. self._name .. " not opened for writing"
        end

        local toWrite, writeSize
        if type(data) == 'string' then
                writeSize = (size == nil or size == 'all') and #data or size
                toWrite = data
        else
                writeSize = (size == nil or size == 'all') and data:getSize() or size
                toWrite = data:getFFIPointer()
        end

        if tonumber(C.fwrite(toWrite, 1, writeSize, self._handle)) ~= writeSize then
                return false, "Could not write data"
        end
        return true
end

function File:seek(pos)
        return self._handle and C.fseek(self._handle, pos, 0) == 0
end

function File:tell()
        if not self._handle then return nil, "Invalid position" end
        return tonumber(C.ftell(self._handle))
end

function File:flush()
        if self._mode ~= 'w' and self._mode ~= 'a' then
                return nil, "File is not opened for writing"
        end
        return C.fflush(self._handle) == 0
end

function File:isEOF()
        return not self:isOpen() or C.feof(self._handle) ~= 0 or self:tell() == self:getSize()
end

function File:release()
        if self._mode ~= 'c' then self:close() end
        self._handle = nil
end

function File:type() return 'File' end

function File:typeOf(t) return t == 'File' end

File.__index = File

-----------------------------------------------------------------------------

local nativefs = {}
local loveC = ffi.os == 'Windows' and ffi.load('love') or C

function nativefs.newFile(name)
        if type(name) ~= 'string' then
                error("bad argument #1 to 'newFile' (string expected, got " .. type(name) .. ")")
        end
        return setmetatable({
                _name = name,
                _mode = 'c',
                _handle = nil,
                _bufferSize = 0,
                _bufferMode = 'none'
        }, File)
end

function nativefs.newFileData(filepath)
        local f = nativefs.newFile(filepath)
        local ok, err = f:open('r')
        if not ok then return nil, err end

        local data, err = f:read('data', 'all')
        f:close()
        return data, err
end

function nativefs.mount(archive, mountPoint, appendToPath)
        return loveC.PHYSFS_mount(archive, mountPoint, appendToPath and 1 or 0) ~= 0
end

function nativefs.unmount(archive)
        return loveC.PHYSFS_unmount(archive) ~= 0
end

function nativefs.read(containerOrName, nameOrSize, sizeOrNil)
        local container, name, size
        if sizeOrNil then
                container, name, size = containerOrName, nameOrSize, sizeOrNil
        elseif not nameOrSize then
                container, name, size = 'string', containerOrName, 'all'
        else
                if type(nameOrSize) == 'number' or nameOrSize == 'all' then
                        container, name, size = 'string', containerOrName, nameOrSize
                else
                        container, name, size = containerOrName, nameOrSize, 'all'
                end
        end

        local file = nativefs.newFile(name)
        local ok, err = file:open('r')
        if not ok then return nil, err end

        local data, size = file:read(container, size)
        file:close()
        return data, size
end

local function writeFile(mode, name, data, size)
        local file = nativefs.newFile(name)
        local ok, err = file:open(mode)
        if not ok then return nil, err end

        ok, err = file:write(data, size or 'all')
        file:close()
        return ok, err
end

function nativefs.write(name, data, size)
        return writeFile('w', name, data, size)
end

function nativefs.append(name, data, size)
        return writeFile('a', name, data, size)
end

function nativefs.lines(name)
        local f = nativefs.newFile(name)
        local ok, err = f:open('r')
        if not ok then return nil, err end
        return lines(f, true)
end

function nativefs.load(name)
        local chunk, err = nativefs.read(name)
        if not chunk then return nil, err end
        return loadstring(chunk, name)
end

function nativefs.getWorkingDirectory()
        return getcwd()
end

function nativefs.setWorkingDirectory(path)
        if not chdir(path) then return false, "Could not set working directory" end
        return true
end

function nativefs.getDriveList()
        if ffi.os ~= 'Windows' then return { '/' } end
        local drives, bits = {}, C.GetLogicalDrives()
        for i = 0, 25 do
                if bit.band(bits, 2 ^ i) > 0 then
                        table.insert(drives, string.char(65 + i) .. ':/')
                end
        end
        return drives
end

function nativefs.createDirectory(path)
        local current = path:sub(1, 1) == '/' and '/' or ''
        for dir in path:gmatch('[^/\\]+') do
                current = current .. dir .. '/'
                local info = nativefs.getInfo(current, 'directory')
                if not info and not mkdir(current) then return false, "Could not create directory " .. current end
        end
        return true
end

function nativefs.remove(name)
        local info = nativefs.getInfo(name)
        if not info then return false, "Could not remove " .. name end
        if info.type == 'directory' then
                if not rmdir(name) then return false, "Could not remove directory " .. name end
                return true
        end
        if not unlink(name) then return false, "Could not remove file " .. name end
        return true
end

local function withTempMount(dir, fn, ...)
        local mountPoint = _ptr(loveC.PHYSFS_getMountPoint(dir))
        if mountPoint then return fn(ffi.string(mountPoint), ...) end
        if not nativefs.mount(dir, '__nativefs__temp__') then return false, "Could not mount " .. dir end
        local a, b = fn('__nativefs__temp__', ...)
        nativefs.unmount(dir)
        return a, b
end

function nativefs.getDirectoryItems(dir)
        if type(dir) ~= "string" then
                error("bad argument #1 to 'getDirectoryItems' (string expected, got " .. type(dir) .. ")")
        end
        local result, err = withTempMount(dir, love.filesystem.getDirectoryItems)
        return result or {}
end

local function getDirectoryItemsInfo(path, filtertype)
        local items = {}
        local files = love.filesystem.getDirectoryItems(path)
        for i = 1, #files do
                local filepath = string.format('%s/%s', path, files[i])
                local info = love.filesystem.getInfo(filepath, filtertype)
                if info then
                        info.name = files[i]
                        table.insert(items, info)
                end
        end
        return items
end

function nativefs.getDirectoryItemsInfo(path, filtertype)
        if type(path) ~= "string" then
                error("bad argument #1 to 'getDirectoryItemsInfo' (string expected, got " .. type(path) .. ")")
        end
        local result, err = withTempMount(path, getDirectoryItemsInfo, filtertype)
        return result or {}
end

local function getInfo(path, file, filtertype)
        local filepath = string.format('%s/%s', path, file)
        return love.filesystem.getInfo(filepath, filtertype)
end

local function leaf(p)
        p = p:gsub('\\', '/')
        local last, a = p, 1
        while a do
                a = p:find('/', a + 1)
                if a then
                        last = p:sub(a + 1)
                end
        end
        return last
end

function nativefs.getInfo(path, filtertype)
        if type(path) ~= 'string' then
                error("bad argument #1 to 'getInfo' (string expected, got " .. type(path) .. ")")
        end
        local dir = path:match("(.*[\\/]).*$") or './'
        local file = leaf(path)
        local result, err = withTempMount(dir, getInfo, file, filtertype)
        return result or nil
end

-----------------------------------------------------------------------------

MODEMAP = { r = 'rb', w = 'wb', a = 'ab' }
local MAX_PATH = 4096

ffi.cdef([[
        int PHYSFS_mount(const char* dir, const char* mountPoint, int appendToPath);
        int PHYSFS_unmount(const char* dir);
        const char* PHYSFS_getMountPoint(const char* dir);

        typedef struct FILE FILE;

        FILE* fopen(const char* path, const char* mode);
        size_t fread(void* ptr, size_t size, size_t nmemb, FILE* stream);
        size_t fwrite(const void* ptr, size_t size, size_t nmemb, FILE* stream);
        int fclose(FILE* stream);
        int fflush(FILE* stream);
        size_t fseek(FILE* stream, size_t offset, int whence);
        size_t ftell(FILE* stream);
        int setvbuf(FILE* stream, char* buffer, int mode, size_t size);
        int feof(FILE* stream);
]])

if ffi.os == 'Windows' then
        ffi.cdef([[
                int MultiByteToWideChar(unsigned int cp, uint32_t flags, const char* mb, int cmb, const wchar_t* wc, int cwc);
                int WideCharToMultiByte(unsigned int cp, uint32_t flags, const wchar_t* wc, int cwc, const char* mb,
                                        int cmb, const char* def, int* used);
                int GetLogicalDrives(void);
                int CreateDirectoryW(const wchar_t* path, void*);
                int _wchdir(const wchar_t* path);
                wchar_t* _wgetcwd(wchar_t* buffer, int maxlen);
                FILE* _wfopen(const wchar_t* path, const wchar_t* mode);
                int _wunlink(const wchar_t* path);
                int _wrmdir(const wchar_t* path);
        ]])

        BUFFERMODE = { full = 0, line = 64, none = 4 }

        local function towidestring(str)
                local size = C.MultiByteToWideChar(65001, 0, str, #str, nil, 0)
                local buf = ffi.new('wchar_t[?]', size + 1)
                C.MultiByteToWideChar(65001, 0, str, #str, buf, size)
                return buf
        end

        local function toutf8string(wstr)
                local size = C.WideCharToMultiByte(65001, 0, wstr, -1, nil, 0, nil, nil)
                local buf = ffi.new('char[?]', size + 1)
                C.WideCharToMultiByte(65001, 0, wstr, -1, buf, size, nil, nil)
                return ffi.string(buf)
        end

        local nameBuffer = ffi.new('wchar_t[?]', MAX_PATH + 1)

        fopen = function(path, mode) return C._wfopen(towidestring(path), towidestring(mode)) end
        getcwd = function() return toutf8string(C._wgetcwd(nameBuffer, MAX_PATH)) end
        chdir = function(path) return C._wchdir(towidestring(path)) == 0 end
        unlink = function(path) return C._wunlink(towidestring(path)) == 0 end
        mkdir = function(path) return C.CreateDirectoryW(towidestring(path), nil) ~= 0 end
        rmdir = function(path) return C._wrmdir(towidestring(path)) == 0 end
else
        BUFFERMODE = { full = 0, line = 1, none = 2 }

        ffi.cdef([[
                char* getcwd(char *buffer, int maxlen);
                int chdir(const char* path);
                int unlink(const char* path);
                int mkdir(const char* path, int mode);
                int rmdir(const char* path);
        ]])

        local nameBuffer = ByteArray(MAX_PATH)

        fopen = C.fopen
        unlink = function(path) return ffi.C.unlink(path) == 0 end
        chdir = function(path) return ffi.C.chdir(path) == 0 end
        mkdir = function(path) return ffi.C.mkdir(path, 0x1ed) == 0 end
        rmdir = function(path) return ffi.C.rmdir(path) == 0 end

        getcwd = function()
                local cwd = _ptr(C.getcwd(nameBuffer, MAX_PATH))
                return cwd and ffi.string(cwd) or nil
        end
end

return nativefs