Make ffmpeg skills compareable

autocert/autocert.go

@@ -169,7 +169,7 @@ func (m *manager) HTTPChallengeResolver(ctx context.Context, listenAddress strin
 // AcquireCertificates tries to acquire the certificates for the given hostnames synchronously.
 func (m *manager) AcquireCertificates(ctx context.Context, hostnames []string) error {
 	m.lock.Lock()
-	added, removed := slices.Diff(hostnames, m.hostnames)
+	added, removed := slices.DiffComparable(hostnames, m.hostnames)
 	m.lock.Unlock()
 
 	var err error
@@ -202,7 +202,7 @@ func (m *manager) AcquireCertificates(ctx context.Context, hostnames []string) e
 // ManageCertificates is the same as AcquireCertificates but it does it in the background.
 func (m *manager) ManageCertificates(ctx context.Context, hostnames []string) error {
 	m.lock.Lock()
-	added, removed := slices.Diff(hostnames, m.hostnames)
+	added, removed := slices.DiffComparable(hostnames, m.hostnames)
 	m.hostnames = make([]string, len(hostnames))
 	copy(m.hostnames, hostnames)
 	m.lock.Unlock()

ffmpeg/skills/data.go

@@ -0,0 +1,57 @@
+package skills
+
+var ffmpegdata = `ffmpeg version 4.4.1-datarhei Copyright (c) 2000-2021 the FFmpeg developers
+built with gcc 10.3.1 (Alpine 10.3.1_git20211027) 20211027
+configuration: --extra-version=datarhei --prefix=/usr --extra-libs='-lpthread -lm -lz -lsupc++ -lstdc++ -lssl -lcrypto -lz -lc -ldl' --enable-nonfree --enable-gpl --enable-version3 --enable-postproc --enable-static --enable-openssl --enable-omx --enable-omx-rpi --enable-mmal --enable-v4l2_m2m --enable-libfreetype --enable-libsrt --enable-libx264 --enable-libx265 --enable-libvpx --enable-libmp3lame --enable-libopus --enable-libvorbis --disable-ffplay --disable-debug --disable-doc --disable-shared
+libavutil      56. 70.100 / 56. 70.100
+libavcodec     58.134.100 / 58.134.100
+libavformat    58. 76.100 / 58. 76.100
+libavdevice    58. 13.100 / 58. 13.100
+libavfilter     7.110.100 /  7.110.100
+libswscale      5.  9.100 /  5.  9.100
+libswresample   3.  9.100 /  3.  9.100
+libpostproc    55.  9.100 / 55.  9.100`
+
+var filterdata = ` ... afirsrc           |->A       Generate a FIR coefficients audio stream.
+... anoisesrc         |->A       Generate a noise audio signal.
+... anullsrc          |->A       Null audio source, return empty audio frames.
+... hilbert           |->A       Generate a Hilbert transform FIR coefficients.
+... sinc              |->A       Generate a sinc kaiser-windowed low-pass, high-pass, band-pass, or band-reject FIR coefficients.
+... sine              |->A       Generate sine wave audio signal.
+... anullsink         A->|       Do absolutely nothing with the input audio.
+... addroi            V->V       Add region of interest to frame.
+... alphaextract      V->N       Extract an alpha channel as a grayscale image component.
+T.. alphamerge        VV->V      Copy the luma value of the second input into the alpha channel of the first input.`
+
+var codecdata = ` DEAIL. aac                  AAC (Advanced Audio Coding) (decoders: aac aac_fixed aac_at ) (encoders: aac aac_at )
+DEVI.S y41p                 Uncompressed YUV 4:1:1 12-bit
+DEV.LS h264                 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (encoders: libx264 libx264rgb h264_videotoolbox )
+DEV.L. flv1                 FLV / Sorenson Spark / Sorenson H.263 (Flash Video) (decoders: flv ) (encoders: flv )`
+
+var formatdata = ` DE mpeg            MPEG-1 Systems / MPEG program stream
+ E  mpeg1video      raw MPEG-1 video
+ E  mpeg2video      raw MPEG-2 video
+DE  mpegts          MPEG-TS (MPEG-2 Transport Stream)
+D   mpegtsraw       raw MPEG-TS (MPEG-2 Transport Stream)
+D   mpegvideo       raw MPEG video`
+
+var protocoldata = `Input:
+async
+bluray
+cache
+Output:
+crypto
+file
+ftp
+gopher`
+
+var hwacceldata = `Hardware acceleration methods:
+videotoolbox`
+
+var v4ldata = `mmal service 16.1 (platform:bcm2835-v4l2):
+	/dev/video0
+
+Webcam C170: Webcam C170 (usb-3f980000.usb-1.3):
+	/dev/video1
+
+`

ffmpeg/skills/skills.go

@@ -11,6 +11,8 @@ import (
 	"os/exec"
 	"regexp"
 	"strings"
+
+	"github.com/datarhei/core/v16/slices"
 )
 
 // Codec represents a codec with its availabe encoders and decoders
@@ -21,12 +23,48 @@ type Codec struct {
 	Decoders []string
 }
 
+func (a Codec) Equal(b Codec) bool {
+	if a.Id != b.Id {
+		return false
+	}
+
+	if a.Name != b.Name {
+		return false
+	}
+
+	if !slices.EqualComparableElements(a.Encoders, b.Encoders) {
+		return false
+	}
+
+	if !slices.EqualComparableElements(a.Decoders, b.Decoders) {
+		return false
+	}
+
+	return true
+}
+
 type ffCodecs struct {
 	Audio    []Codec
 	Video    []Codec
 	Subtitle []Codec
 }
 
+func (a ffCodecs) Equal(b ffCodecs) bool {
+	if !slices.EqualEqualerElements(a.Audio, b.Audio) {
+		return false
+	}
+
+	if !slices.EqualEqualerElements(a.Video, b.Video) {
+		return false
+	}
+
+	if !slices.EqualEqualerElements(a.Subtitle, b.Subtitle) {
+		return false
+	}
+
+	return true
+}
+
 // HWDevice represents a hardware device (e.g. USB device)
 type HWDevice struct {
 	Id    string
@@ -35,6 +73,26 @@ type HWDevice struct {
 	Media string
 }
 
+func (a HWDevice) Equal(b HWDevice) bool {
+	if a.Id != b.Id {
+		return false
+	}
+
+	if a.Name != b.Name {
+		return false
+	}
+
+	if a.Extra != b.Extra {
+		return false
+	}
+
+	if a.Media != b.Media {
+		return false
+	}
+
+	return true
+}
+
 // Device represents a type of device (e.g. V4L2) including connected actual devices
 type Device struct {
 	Id      string
@@ -42,11 +100,39 @@ type Device struct {
 	Devices []HWDevice
 }
 
+func (a Device) Equal(b Device) bool {
+	if a.Id != b.Id {
+		return false
+	}
+
+	if a.Name != b.Name {
+		return false
+	}
+
+	if !slices.EqualEqualerElements(a.Devices, b.Devices) {
+		return false
+	}
+
+	return true
+}
+
 type ffDevices struct {
 	Demuxers []Device
 	Muxers   []Device
 }
 
+func (a ffDevices) Equal(b ffDevices) bool {
+	if !slices.EqualEqualerElements(a.Demuxers, b.Demuxers) {
+		return false
+	}
+
+	if !slices.EqualEqualerElements(a.Muxers, b.Muxers) {
+		return false
+	}
+
+	return true
+}
+
 // Format represents a supported format (e.g. flv)
 type Format struct {
 	Id   string
@@ -58,6 +144,18 @@ type ffFormats struct {
 	Muxers   []Format
 }
 
+func (a ffFormats) Equal(b ffFormats) bool {
+	if !slices.EqualComparableElements(a.Demuxers, b.Demuxers) {
+		return false
+	}
+
+	if !slices.EqualComparableElements(a.Muxers, b.Muxers) {
+		return false
+	}
+
+	return true
+}
+
 // Protocol represents a supported protocol (e.g. rtsp)
 type Protocol struct {
 	Id   string
@@ -69,6 +167,18 @@ type ffProtocols struct {
 	Output []Protocol
 }
 
+func (a ffProtocols) Equal(b ffProtocols) bool {
+	if !slices.EqualComparableElements(a.Input, b.Input) {
+		return false
+	}
+
+	if !slices.EqualComparableElements(a.Output, b.Output) {
+		return false
+	}
+
+	return true
+}
+
 type HWAccel struct {
 	Id   string
 	Name string
@@ -94,6 +204,26 @@ type ffmpeg struct {
 	Libraries     []Library
 }
 
+func (a ffmpeg) Equal(b ffmpeg) bool {
+	if a.Version != b.Version {
+		return false
+	}
+
+	if a.Compiler != b.Compiler {
+		return false
+	}
+
+	if a.Configuration != b.Configuration {
+		return false
+	}
+
+	if !slices.EqualComparableElements(a.Libraries, b.Libraries) {
+		return false
+	}
+
+	return true
+}
+
 // Skills are the detected capabilities of a ffmpeg binary
 type Skills struct {
 	FFmpeg ffmpeg
@@ -107,6 +237,38 @@ type Skills struct {
 	Protocols ffProtocols
 }
 
+func (a Skills) Equal(b Skills) bool {
+	if !a.FFmpeg.Equal(b.FFmpeg) {
+		return false
+	}
+
+	if !slices.EqualComparableElements(a.Filters, b.Filters) {
+		return false
+	}
+
+	if !slices.EqualComparableElements(a.HWAccels, b.HWAccels) {
+		return false
+	}
+
+	if !a.Codecs.Equal(b.Codecs) {
+		return false
+	}
+
+	if !a.Devices.Equal(b.Devices) {
+		return false
+	}
+
+	if !a.Formats.Equal(b.Formats) {
+		return false
+	}
+
+	if !a.Protocols.Equal(b.Protocols) {
+		return false
+	}
+
+	return true
+}
+
 // New returns all skills that ffmpeg provides
 func New(binary string) (Skills, error) {
 	c := Skills{}
@@ -193,7 +355,7 @@ func filters(binary string) []Filter {
 func parseFilters(data []byte) []Filter {
 	filters := []Filter{}
 
-	re := regexp.MustCompile(`^\s[TSC.]{3} ([0-9A-Za-z_]+)\s+(?:.*?)\s+(.*)?$`)
+	re := regexp.MustCompile(`^\s*[TSC.]{3} ([0-9A-Za-z_]+)\s+(?:.*?)\s+(.*)?$`)
 
 	scanner := bufio.NewScanner(bytes.NewReader(data))
 	scanner.Split(bufio.ScanLines)
@@ -227,7 +389,7 @@ func codecs(binary string) ffCodecs {
 func parseCodecs(data []byte) ffCodecs {
 	codecs := ffCodecs{}
 
-	re := regexp.MustCompile(`^\s([D.])([E.])([VAS]).{3} ([0-9A-Za-z_]+)\s+(.*?)(?:\(decoders:([^\)]+)\))?\s?(?:\(encoders:([^\)]+)\))?$`)
+	re := regexp.MustCompile(`^\s*([D.])([E.])([VAS]).{3} ([0-9A-Za-z_]+)\s+(.*?)(?:\(decoders:([^\)]+)\))?\s?(?:\(encoders:([^\)]+)\))?$`)
 
 	scanner := bufio.NewScanner(bytes.NewReader(data))
 	scanner.Split(bufio.ScanLines)
@@ -286,7 +448,7 @@ func formats(binary string) ffFormats {
 func parseFormats(data []byte) ffFormats {
 	formats := ffFormats{}
 
-	re := regexp.MustCompile(`^\s([D ])([E ]) ([0-9A-Za-z_,]+)\s+(.*?)$`)
+	re := regexp.MustCompile(`^\s*([D ])([E ])\s+([0-9A-Za-z_,]+)\s+(.*?)$`)
 
 	scanner := bufio.NewScanner(bytes.NewReader(data))
 	scanner.Split(bufio.ScanLines)
@@ -330,7 +492,7 @@ func devices(binary string) ffDevices {
 func parseDevices(data []byte, binary string) ffDevices {
 	devices := ffDevices{}
 
-	re := regexp.MustCompile(`^\s([D ])([E ]) ([0-9A-Za-z_,]+)\s+(.*?)$`)
+	re := regexp.MustCompile(`^\s*([D ])([E ]) ([0-9A-Za-z_,]+)\s+(.*?)$`)
 
 	scanner := bufio.NewScanner(bytes.NewReader(data))
 	scanner.Split(bufio.ScanLines)

ffmpeg/skills/skills_test.go

@@ -1,8 +1,10 @@
 package skills
 
 import (
+	"bytes"
 	"testing"
 
+	"github.com/datarhei/core/v16/slices"
 	"github.com/stretchr/testify/require"
 )
 
@@ -33,6 +35,70 @@ func TestNewInvalidBinary(t *testing.T) {
 	require.Empty(t, skills.Protocols.Output)
 }
 
+func TestEqualEmptySkills(t *testing.T) {
+	s := Skills{}
+
+	ok := s.Equal(s)
+	require.True(t, ok)
+}
+
+func TestEuqalSkills(t *testing.T) {
+	s1 := Skills{
+		FFmpeg:    parseVersion([]byte(ffmpegdata)),
+		Filters:   parseFilters([]byte(filterdata)),
+		HWAccels:  parseHWAccels([]byte(hwacceldata)),
+		Codecs:    parseCodecs([]byte(codecdata)),
+		Devices:   ffDevices{},
+		Formats:   parseFormats([]byte(formatdata)),
+		Protocols: parseProtocols([]byte(protocoldata)),
+	}
+
+	devices := parseV4LDevices(bytes.NewBuffer(slices.Copy([]byte(v4ldata))))
+
+	s1.Devices.Demuxers = append(s1.Devices.Demuxers, Device{
+		Id:      "v4l2",
+		Name:    "webcam",
+		Devices: devices,
+	})
+	s1.Devices.Muxers = append(s1.Devices.Muxers, Device{
+		Id:      "v4l2",
+		Name:    "webcam",
+		Devices: devices,
+	})
+
+	ok := s1.Equal(s1)
+	require.True(t, ok)
+
+	s2 := Skills{
+		FFmpeg:    parseVersion([]byte(ffmpegdata)),
+		Filters:   parseFilters([]byte(filterdata)),
+		HWAccels:  parseHWAccels([]byte(hwacceldata)),
+		Codecs:    parseCodecs([]byte(codecdata)),
+		Devices:   ffDevices{},
+		Formats:   parseFormats([]byte(formatdata)),
+		Protocols: parseProtocols([]byte(protocoldata)),
+	}
+
+	devices = parseV4LDevices(bytes.NewBuffer(slices.Copy([]byte(v4ldata))))
+
+	s2.Devices.Demuxers = append(s2.Devices.Demuxers, Device{
+		Id:      "v4l2",
+		Name:    "webcam",
+		Devices: devices,
+	})
+	s2.Devices.Muxers = append(s2.Devices.Muxers, Device{
+		Id:      "v4l2",
+		Name:    "webcam",
+		Devices: devices,
+	})
+
+	ok = s1.Equal(s2)
+	require.True(t, ok)
+
+	ok = s1.Equal(Skills{})
+	require.False(t, ok)
+}
+
 func TestPatchVersion(t *testing.T) {
 	data := `ffmpeg version 4.3.1 Copyright (c) 2000-2020 the FFmpeg developers
  built with Apple clang version 12.0.0 (clang-1200.0.32.29)
@@ -162,17 +228,7 @@ func TestMinorVersion(t *testing.T) {
 }
 
 func TestCustomVersion(t *testing.T) {
-	data := `ffmpeg version 4.4.1-datarhei Copyright (c) 2000-2021 the FFmpeg developers
+	data := ffmpegdata
-built with gcc 10.3.1 (Alpine 10.3.1_git20211027) 20211027
-configuration: --extra-version=datarhei --prefix=/usr --extra-libs='-lpthread -lm -lz -lsupc++ -lstdc++ -lssl -lcrypto -lz -lc -ldl' --enable-nonfree --enable-gpl --enable-version3 --enable-postproc --enable-static --enable-openssl --enable-omx --enable-omx-rpi --enable-mmal --enable-v4l2_m2m --enable-libfreetype --enable-libsrt --enable-libx264 --enable-libx265 --enable-libvpx --enable-libmp3lame --enable-libopus --enable-libvorbis --disable-ffplay --disable-debug --disable-doc --disable-shared
-libavutil      56. 70.100 / 56. 70.100
-libavcodec     58.134.100 / 58.134.100
-libavformat    58. 76.100 / 58. 76.100
-libavdevice    58. 13.100 / 58. 13.100
-libavfilter     7.110.100 /  7.110.100
-libswscale      5.  9.100 /  5.  9.100
-libswresample   3.  9.100 /  3.  9.100
-libpostproc    55.  9.100 / 55.  9.100`
 
 	f := parseVersion([]byte(data))
 
@@ -226,16 +282,7 @@ libpostproc    55.  9.100 / 55.  9.100`
 }
 
 func TestFilters(t *testing.T) {
-	data := ` ... afirsrc           |->A       Generate a FIR coefficients audio stream.
+	data := filterdata
- ... anoisesrc         |->A       Generate a noise audio signal.
- ... anullsrc          |->A       Null audio source, return empty audio frames.
- ... hilbert           |->A       Generate a Hilbert transform FIR coefficients.
- ... sinc              |->A       Generate a sinc kaiser-windowed low-pass, high-pass, band-pass, or band-reject FIR coefficients.
- ... sine              |->A       Generate sine wave audio signal.
- ... anullsink         A->|       Do absolutely nothing with the input audio.
- ... addroi            V->V       Add region of interest to frame.
- ... alphaextract      V->N       Extract an alpha channel as a grayscale image component.
- T.. alphamerge        VV->V      Copy the luma value of the second input into the alpha channel of the first input.`
 
 	f := parseFilters([]byte(data))
 
@@ -284,10 +331,7 @@ func TestFilters(t *testing.T) {
 }
 
 func TestCodecs(t *testing.T) {
-	data := ` DEAIL. aac                  AAC (Advanced Audio Coding) (decoders: aac aac_fixed aac_at ) (encoders: aac aac_at )
+	data := codecdata
-	DEVI.S y41p                 Uncompressed YUV 4:1:1 12-bit
-	DEV.LS h264                 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (encoders: libx264 libx264rgb h264_videotoolbox )
-	DEV.L. flv1                 FLV / Sorenson Spark / Sorenson H.263 (Flash Video) (decoders: flv ) (encoders: flv )`
 
 	c := parseCodecs([]byte(data))
 
@@ -346,12 +390,7 @@ func TestCodecs(t *testing.T) {
 }
 
 func TestFormats(t *testing.T) {
-	data := ` DE mpeg            MPEG-1 Systems / MPEG program stream
+	data := formatdata
-  E mpeg1video      raw MPEG-1 video
-  E mpeg2video      raw MPEG-2 video
- DE mpegts          MPEG-TS (MPEG-2 Transport Stream)
- D  mpegtsraw       raw MPEG-TS (MPEG-2 Transport Stream)
- D  mpegvideo       raw MPEG video`
 
 	f := parseFormats([]byte(data))
 
@@ -396,15 +435,7 @@ func TestFormats(t *testing.T) {
 }
 
 func TestProtocols(t *testing.T) {
-	data := `Input:
+	data := protocoldata
-	async
-	bluray
-	cache
-Output:
-	crypto
-	file
-	ftp
-	gopher`
 
 	p := parseProtocols([]byte(data))
 
@@ -445,8 +476,7 @@ Output:
 }
 
 func TestHWAccels(t *testing.T) {
-	data := `Hardware acceleration methods:
+	data := hwacceldata
-videotoolbox`
 
 	p := parseHWAccels([]byte(data))
 

ffmpeg/skills/v4l2_test.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"testing"
 
+	"github.com/datarhei/core/v16/slices"
 	"github.com/stretchr/testify/require"
 )
 
@@ -16,15 +17,9 @@ func TestNoV4LDevices(t *testing.T) {
 }
 
 func TestV4LDevices(t *testing.T) {
-	data := bytes.NewBufferString(`mmal service 16.1 (platform:bcm2835-v4l2):
+	data := v4ldata
-	/dev/video0
 
-Webcam C170: Webcam C170 (usb-3f980000.usb-1.3):
+	devices := parseV4LDevices(bytes.NewBuffer(slices.Copy([]byte(data))))
-	/dev/video1
-
-`)
-
-	devices := parseV4LDevices(data)
 
 	require.Equal(t, []HWDevice{
 		{

slices/copy.go

@@ -6,3 +6,17 @@ func Copy[T any](src []T) []T {
 
 	return dst
 }
+
+type Cloner[T any] interface {
+	Clone() T
+}
+
+func CopyDeep[T any, X Cloner[T]](src []X) []T {
+	dst := make([]T, len(src))
+
+	for i, c := range src {
+		dst[i] = c.Clone()
+	}
+
+	return dst
+}

slices/copy_test.go

@@ -13,3 +13,15 @@ func TestCopy(t *testing.T) {
 
 	require.Equal(t, []string{"a", "b", "c"}, b)
 }
+
+func (a String) Clone() String {
+	return String(string(a))
+}
+
+func TestCopyDeep(t *testing.T) {
+	a := []String{"a", "b", "c"}
+
+	b := CopyDeep[String](a)
+
+	require.Equal(t, []String{"a", "b", "c"}, b)
+}

slices/diff.go

@@ -1,28 +1,81 @@
 package slices
 
-// Diff returns a sliceof newly added entries and a slice of removed entries based
+// DiffComparable diffs two arrays/slices and returns slices of elements that are only in A and only in B.
-// the provided slices.
+// If some element is present multiple times, each instance is counted separately (e.g. if something is 2x in A and
-func Diff[T comparable](next, current []T) ([]T, []T) {
+// 5x in B, it will be 0x in extraA and 3x in extraB). The order of items in both lists is ignored.
-	added, removed := []T{}, []T{}
+// Adapted from https://github.com/stretchr/testify/blob/f97607b89807936ac4ff96748d766cf4b9711f78/assert/assertions.go#L1073C21-L1073C21
+func DiffComparable[T comparable](listA, listB []T) ([]T, []T) {
+	extraA, extraB := []T{}, []T{}
 
-	currentMap := map[T]struct{}{}
+	aLen := len(listA)
+	bLen := len(listB)
 
-	for _, name := range current {
+	// Mark indexes in listA that we already used
-		currentMap[name] = struct{}{}
+	visited := make([]bool, bLen)
+	for i := 0; i < aLen; i++ {
+		element := listA[i]
+		found := false
+		for j := 0; j < bLen; j++ {
+			if visited[j] {
+				continue
+			}
+			if listB[j] == element {
+				visited[j] = true
+				found = true
+				break
+			}
+		}
+		if !found {
+			extraA = append(extraA, element)
+		}
 	}
 
-	for _, name := range next {
+	for j := 0; j < bLen; j++ {
-		if _, ok := currentMap[name]; ok {
+		if visited[j] {
-			delete(currentMap, name)
 			continue
 		}
-
+		extraB = append(extraB, listB[j])
-		added = append(added, name)
 	}
 
-	for name := range currentMap {
+	return extraA, extraB
-		removed = append(removed, name)
+}
-	}
+
-
+// DiffEqualer diffs two arrays/slices where each element implements the Equaler interface and returns slices of
-	return added, removed
+// elements that are only in A and only in B. If some element is present multiple times, each instance is counted
+// separately (e.g. if something is 2x in A and 5x in B, it will be 0x in extraA and 3x in extraB). The order of
+// items in both lists is ignored.
+func DiffEqualer[T any, X Equaler[T]](listA []T, listB []X) ([]T, []X) {
+	extraA, extraB := []T{}, []X{}
+
+	aLen := len(listA)
+	bLen := len(listB)
+
+	// Mark indexes in listA that we already used
+	visited := make([]bool, bLen)
+	for i := 0; i < aLen; i++ {
+		element := listA[i]
+		found := false
+		for j := 0; j < bLen; j++ {
+			if visited[j] {
+				continue
+			}
+			if listB[j].Equal(element) {
+				visited[j] = true
+				found = true
+				break
+			}
+		}
+		if !found {
+			extraA = append(extraA, element)
+		}
+	}
+
+	for j := 0; j < bLen; j++ {
+		if visited[j] {
+			continue
+		}
+		extraB = append(extraB, listB[j])
+	}
+
+	return extraA, extraB
 }

slices/diff_test.go

@@ -6,12 +6,22 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestDiff(t *testing.T) {
+func TestDiffComparable(t *testing.T) {
 	a := []string{"c", "d", "e", "f"}
-	b := []string{"a", "b", "c", "d"}
+	b := []string{"a", "a", "b", "c", "d"}
 
-	added, removed := Diff(a, b)
+	added, removed := DiffComparable(a, b)
 
 	require.ElementsMatch(t, []string{"e", "f"}, added)
-	require.ElementsMatch(t, []string{"a", "b"}, removed)
+	require.ElementsMatch(t, []string{"a", "a", "b"}, removed)
+}
+
+func TestDiffEqualer(t *testing.T) {
+	a := []String{"c", "d", "e", "f"}
+	b := []String{"a", "a", "b", "c", "d"}
+
+	added, removed := DiffComparable(a, b)
+
+	require.ElementsMatch(t, []String{"e", "f"}, added)
+	require.ElementsMatch(t, []String{"a", "a", "b"}, removed)
 }

slices/equal.go

@@ -0,0 +1,28 @@
+package slices
+
+// EqualComparableElements returns whether two slices have the same elements.
+func EqualComparableElements[T comparable](a, b []T) bool {
+	extraA, extraB := DiffComparable(a, b)
+
+	if len(extraA) == 0 && len(extraB) == 0 {
+		return true
+	}
+
+	return false
+}
+
+// Equaler defines a type that implements the Equal function.
+type Equaler[T any] interface {
+	Equal(T) bool
+}
+
+// EqualEqualerElements returns whether two slices of Equaler have the same elements.
+func EqualEqualerElements[T any, X Equaler[T]](a []T, b []X) bool {
+	extraA, extraB := DiffEqualer(a, b)
+
+	if len(extraA) == 0 && len(extraB) == 0 {
+		return true
+	}
+
+	return false
+}

slices/equal_test.go

@@ -0,0 +1,51 @@
+package slices
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestEqualComparableElements(t *testing.T) {
+	a := []string{"a", "b", "c", "d"}
+	b := []string{"b", "c", "a", "d"}
+
+	ok := EqualComparableElements(a, b)
+	require.True(t, ok)
+
+	ok = EqualComparableElements(b, a)
+	require.True(t, ok)
+
+	a = append(a, "z")
+
+	ok = EqualComparableElements(a, b)
+	require.False(t, ok)
+
+	ok = EqualComparableElements(b, a)
+	require.False(t, ok)
+}
+
+type String string
+
+func (a String) Equal(b String) bool {
+	return string(a) == string(b)
+}
+
+func TestEqualEqualerElements(t *testing.T) {
+	a := []String{"a", "b", "c", "d"}
+	b := []String{"b", "c", "a", "d"}
+
+	ok := EqualEqualerElements(a, b)
+	require.True(t, ok)
+
+	ok = EqualEqualerElements(b, a)
+	require.True(t, ok)
+
+	a = append(a, "z")
+
+	ok = EqualEqualerElements(a, b)
+	require.False(t, ok)
+
+	ok = EqualEqualerElements(b, a)
+	require.False(t, ok)
+}