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simplified cartridge loader package
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loader is opened at creation time which allows us to remove the
needlessly complicated pointer-to-pointer mechanism
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@JetSetIlly
JetSetIlly committed Apr 16, 2024
1 parent 18aa6db commit 1f23e72
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Showing 9 changed files with 129 additions and 194 deletions.
161 changes: 57 additions & 104 deletions cartridgeloader/loader.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -28,67 +28,45 @@ import (
"path/filepath"
"slices"
"strings"

"github.com/jetsetilly/gopher2600/hardware/television/specification"
"github.com/jetsetilly/gopher2600/logger"
"github.com/jetsetilly/gopher2600/resources/fs"
)

// Loader abstracts all the ways data can be loaded into the emulation.
type Loader struct {
io.ReadSeeker

// the name to use for the cartridge represented by Loader
// the name to use for the cartridge. in the case of embedded data the name
// will be the name provided to the NewLoaderFromData() function
Name string

// filename of cartridge being loaded. In the case of embedded data, this
// field will contain the name of the data provided to the the
// NewLoaderFromEmbed() function.
// filename of cartridge being loaded. this is the absolute path that was
// used to load the cartridge
//
// in the case of embedded data the filename will be the name provided to
// the NewLoaderFromData() function
//
// use of the Filename can be useful, for example, for checking if the TV
// specification is indicated
Filename string

// empty string or "AUTO" indicates automatic fingerprinting
Mapping string

// any detected TV spec in the filename. will be the empty string if
// nothing is found. note that the empty string is treated like "AUTO" by
// television.SetSpec().
TelevisionSpec string

// expected hash of the loaded cartridge. empty string indicates that the
// hash is unknown and need not be validated. after a load operation the
// value will be the hash of the loaded data
//
// in the case of sound data (IsSoundData is true) then the hash is of the
// original binary file not he decoded PCM data
//
// the value of HashSHA1 will be checked on a call to Loader.Load(). if the
// string is empty then that check passes.
// hashes of data. will be empty if data is being streamed
HashSHA1 string

// HashMD5 is an alternative to hash for use with the properties package
HashMD5 string
HashMD5 string

// does the Data field consist of sound (PCM) data
IsSoundData bool

// cartridge data. empty until Load() is called unless the loader was
// created by NewLoaderFromEmbed()
//
// the pointer-to-a-slice construct allows the cartridge to be
// loaded/changed by a Loader instance that has been passed by value.
Data *[]byte
// cartridge data
Data []byte

data *bytes.Buffer

// if stream is nil then the data will not be streamed. if *stream is nil
// then the stream is not open
//
// (this is a tricky construct but it allows an instance of Loader to be
// passed by value but still be able to close an opened stream at an
// "earlier" point in the code)
stream **os.File
// if stream is nil then the data is not streamed
stream *os.File

// whether the Loader was created with NewLoaderFromData()
// data was supplied through NewLoaderFromData()
embedded bool
}

Expand All @@ -112,20 +90,20 @@ var NoFilename = errors.New("no filename")
// mixture of both.
//
// Filenames can contain whitespace, including leading and trailing whitespace,
// but cannot consists only of whitespace.
// but cannot consist only of whitespace.
func NewLoaderFromFilename(filename string, mapping string) (Loader, error) {
// check filename but don't change it. we don't want to allow the empty
// string or a string only consisting of whitespace, but we *do* want to
// allow filenames with leading/trailing spaces
if strings.TrimSpace(filename) == "" {
return Loader{}, fmt.Errorf("catridgeloader: %w", NoFilename)
return Loader{}, fmt.Errorf("loader: %w", NoFilename)
}

// absolute path of filename
var err error
filename, err = fs.Abs(filename)
filename, err = filepath.Abs(filename)
if err != nil {
return Loader{}, fmt.Errorf("catridgeloader: %w", err)
return Loader{}, fmt.Errorf("loader: %w", err)
}

mapping = strings.TrimSpace(strings.ToUpper(mapping))
Expand All @@ -138,10 +116,6 @@ func NewLoaderFromFilename(filename string, mapping string) (Loader, error) {
Mapping: mapping,
}

// create an empty slice for the Data field to refer to
data := make([]byte, 0)
ld.Data = &data

// decide what mapping to use if the requested mapping is AUTO
if mapping == "AUTO" {
extension := strings.ToUpper(filepath.Ext(filename))
Expand All @@ -160,7 +134,7 @@ func NewLoaderFromFilename(filename string, mapping string) (Loader, error) {
if ld.Mapping == "AUTO" {
ok, err := miniFingerprintMovieCart(filename)
if err != nil {
return Loader{}, fmt.Errorf("catridgeloader: %w", err)
return Loader{}, fmt.Errorf("loader: %w", err)
}
if ok {
ld.Mapping = "MVC"
Expand All @@ -170,11 +144,13 @@ func NewLoaderFromFilename(filename string, mapping string) (Loader, error) {
// create stream pointer only for streaming sources. these file formats are
// likely to be very large by comparison to regular cartridge files.
if ld.Mapping == "MVC" || (ld.Mapping == "AR" && ld.IsSoundData) {
ld.stream = new(*os.File)
err = ld.openStream()
} else {
err = ld.open()
}
if err != nil {
return Loader{}, fmt.Errorf("loader: %w", err)
}

// check filename for information about the TV specifction
ld.TelevisionSpec = specification.SearchSpec(filename)

// decide on the name for this cartridge
ld.Name = decideOnName(ld)
Expand All @@ -193,12 +169,12 @@ func NewLoaderFromFilename(filename string, mapping string) (Loader, error) {
// used.
func NewLoaderFromData(name string, data []byte, mapping string) (Loader, error) {
if len(data) == 0 {
return Loader{}, fmt.Errorf("catridgeloader: emebedded data is empty")
return Loader{}, fmt.Errorf("loader: emebedded data is empty")
}

name = strings.TrimSpace(name)
if name == "" {
return Loader{}, fmt.Errorf("catridgeloader: no name for embedded data")
return Loader{}, fmt.Errorf("loader: no name for embedded data")
}

mapping = strings.TrimSpace(strings.ToUpper(mapping))
Expand All @@ -209,11 +185,11 @@ func NewLoaderFromData(name string, data []byte, mapping string) (Loader, error)
ld := Loader{
Filename: name,
Mapping: mapping,
Data: &data,
Data: data,
data: bytes.NewBuffer(data),
embedded: true,
HashSHA1: fmt.Sprintf("%x", sha1.Sum(data)),
HashMD5: fmt.Sprintf("%x", md5.Sum(data)),
embedded: true,
}

// decide on the name for this cartridge
Expand All @@ -226,16 +202,15 @@ func NewLoaderFromData(name string, data []byte, mapping string) (Loader, error)
//
// Implements the io.Closer interface.
func (ld Loader) Close() error {
if ld.stream == nil || *ld.stream == nil {
if ld.stream == nil {
return nil
}

err := (**ld.stream).Close()
*ld.stream = nil
err := ld.stream.Close()
ld.stream = nil
if err != nil {
return fmt.Errorf("loader: %w", err)
}
logger.Logf("loader", "stream closed (%s)", ld.Filename)

return nil
}
Expand All @@ -245,49 +220,36 @@ func (ld Loader) Read(p []byte) (int, error) {
if ld.stream == nil {
return ld.data.Read(p)
}

if *ld.stream == nil {
return 0, nil
}

return (*ld.stream).Read(p)
}

// Implements the io.Seeker interface.
func (ld Loader) Seek(offset int64, whence int) (int64, error) {
if ld.stream == nil || *ld.stream == nil {
if ld.stream == nil {
return 0, nil
}
return (*ld.stream).Seek(offset, whence)
}

// Open the cartridge data. Loader filenames with a valid schema will use that
// method to load the data. Currently supported schemes are HTTP and local
// files.
func (ld *Loader) Open() error {
// data is already "opened" when using embedded data
if ld.embedded {
return nil
// open the cartridge data for streaming
func (ld *Loader) openStream() error {
err := ld.Close()
if err != nil {
return fmt.Errorf("loader: %w", err)
}

if ld.stream != nil {
err := ld.Close()
if err != nil {
return fmt.Errorf("loader: %w", err)
}

*ld.stream, err = os.Open(ld.Filename)
if err != nil {
return fmt.Errorf("loader: %w", err)
}
logger.Logf("loader", "stream open (%s)", ld.Filename)

return nil
ld.stream, err = os.Open(ld.Filename)
if err != nil {
return fmt.Errorf("loader: %w", err)
}

if ld.Data != nil && len(*ld.Data) > 0 {
return nil
}
return nil
}

// open the cartridge data. filenames with a valid schema will use that method
// to load the data. currently supported schemes are HTTP and local files.
func (ld *Loader) open() error {
ld.Data = make([]byte, 0)

scheme := "file"

Expand All @@ -306,7 +268,7 @@ func (ld *Loader) Open() error {
}
defer resp.Body.Close()

*ld.Data, err = io.ReadAll(resp.Body)
ld.Data, err = io.ReadAll(resp.Body)
if err != nil {
return fmt.Errorf("loader: %w", err)
}
Expand All @@ -324,26 +286,17 @@ func (ld *Loader) Open() error {
}
defer f.Close()

*ld.Data, err = io.ReadAll(f)
ld.Data, err = io.ReadAll(f)
if err != nil {
return fmt.Errorf("loader: %w", err)
}
}

ld.data = bytes.NewBuffer(*ld.Data)
ld.data = bytes.NewBuffer(ld.Data)

// generate hashes and check for consistency
hash := fmt.Sprintf("%x", sha1.Sum(*ld.Data))
if ld.HashSHA1 != "" && ld.HashSHA1 != hash {
return fmt.Errorf("loader: unexpected SHA1 hash value")
}
ld.HashSHA1 = hash

hash = fmt.Sprintf("%x", md5.Sum(*ld.Data))
if ld.HashMD5 != "" && ld.HashMD5 != hash {
return fmt.Errorf("loader: unexpected MD5 hash value")
}
ld.HashMD5 = hash
// generate hashes
ld.HashSHA1 = fmt.Sprintf("%x", sha1.Sum(ld.Data))
ld.HashMD5 = fmt.Sprintf("%x", md5.Sum(ld.Data))

return nil
}
4 changes: 1 addition & 3 deletions gui/sdlimgui/win_rom_select.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -666,9 +666,7 @@ func (win *winSelectROM) setSelectedFile(filename string) {

// push function to emulation goroutine. result will be checked for in
// draw() function
if err := loader.Open(); err == nil {
win.img.dbg.PushPropertyLookup(loader.HashMD5, win.propertyResult)
}
win.img.dbg.PushPropertyLookup(loader.HashMD5, win.propertyResult)

// create thumbnail animation
win.thmb.Create(loader, thumbnailer.UndefinedNumFrames, true)
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