One image request type instead of five (closes #307)

The new package internal/imagerequest holds the request type, its two
parts Source and Transform, the Format and Fit types, the dimension and
fit checks, the /v1/image/ path parsing and the variant key; it imports
no other package of pixa. imgcache.ParsedURL, imgcache.ImageRequest,
signature.Request, imageprocessor.Request, the second Size, format and
fit types and the conversions between them are gone. The image
processor takes a Transform only. encurl keeps a private struct with the
token's CBOR field names, so tokens made before still decode. VariantKey
moves with the function that makes it. Tests follow the moved and
renamed code; the tests of the removed conversions go with them.

Model: opus-5-5

internal/imgcache/metacache_internal_test.go

@@ -10,23 +10,31 @@ import (
 	"sync"
 	"testing"
 	"time"
+
+	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 
 // webpRequest returns a request for a 100x100 WebP variant of path.
-func webpRequest(path string) *ImageRequest {
-	return &ImageRequest{
-		SourceHost: testHostCDN,
-		SourcePath: path,
-		Size:       Size{Width: 100, Height: 100},
-		Format:     FormatWebP,
-		Quality:    85,
-		FitMode:    FitCover,
+func webpRequest(path string) *imagerequest.Request {
+	return &imagerequest.Request{
+		Source: imagerequest.Source{
+			Host: testHostCDN,
+			Path: path,
+		},
+		Transform: imagerequest.Transform{
+			Size:    imagerequest.Size{Width: 100, Height: 100},
+			Format:  imagerequest.FormatWebP,
+			Quality: 85,
+			FitMode: imagerequest.FitCover,
+		},
 	}
 }
 
 // assertVariantServed checks that GetVariant serves key with the given
 // content and the image/webp content type storeEvictionTestVariant stores.
-func assertVariantServed(t *testing.T, cache *Cache, key VariantKey, content []byte) {
+func assertVariantServed(
+	t *testing.T, cache *Cache, key imagerequest.VariantKey, content []byte,
+) {
 	t.Helper()
 
 	reader, size, contentType, err := cache.GetVariant(key)
@@ -57,7 +65,9 @@ func assertVariantServed(t *testing.T, cache *Cache, key VariantKey, content []b
 
 // assertVariantNotFound checks that GetVariant refuses key with
 // ErrNotFound.
-func assertVariantNotFound(t *testing.T, cache *Cache, key VariantKey) {
+func assertVariantNotFound(
+	t *testing.T, cache *Cache, key imagerequest.VariantKey,
+) {
 	t.Helper()
 
 	reader, _, _, err := cache.GetVariant(key)
@@ -71,16 +81,18 @@ func assertVariantNotFound(t *testing.T, cache *Cache, key VariantKey) {
 }
 
 // assertLookupMisses checks that Lookup reports request as a miss.
-func assertLookupMisses(t *testing.T, cache *Cache, request *ImageRequest) {
+func assertLookupMisses(
+	t *testing.T, cache *Cache, request *imagerequest.Request,
+) {
 	t.Helper()
 
 	lookup, err := cache.Lookup(t.Context(), request)
 	if err != nil {
-		t.Fatalf("Lookup(%s) error = %v", request.SourcePath, err)
+		t.Fatalf("Lookup(%s) error = %v", request.Source.Path, err)
 	}
 
 	if lookup.Hit {
-		t.Errorf("Lookup(%s) is a hit, want a miss", request.SourcePath)
+		t.Errorf("Lookup(%s) is a hit, want a miss", request.Source.Path)
 	}
 }
 
@@ -251,8 +263,8 @@ func TestEvictedVariantIsNotServed(t *testing.T) {
 
 	oldRequest := webpRequest("/old.jpg")
 	newRequest := webpRequest("/new.jpg")
-	oldKey := CacheKey(oldRequest)
-	newKey := CacheKey(newRequest)
+	oldKey := imagerequest.CacheKey(oldRequest)
+	newKey := imagerequest.CacheKey(newRequest)
 	oldContent := bytes.Repeat([]byte{0x01}, 1000)
 	newContent := bytes.Repeat([]byte{0x02}, 1000)
 
@@ -280,7 +292,7 @@ func TestVariantDeletedFromDiskIsNotServed(t *testing.T) {
 	cache, _ := newEvictionTestCache(t, 1<<20)
 
 	request := webpRequest("/deleted.jpg")
-	key := CacheKey(request)
+	key := imagerequest.CacheKey(request)
 	content := []byte("webp variant bytes")
 
 	storeEvictionTestVariant(t, cache, key, content)
@@ -307,7 +319,7 @@ func TestConcurrentVariantStoreReadAndEvict(t *testing.T) {
 
 	for goroutine := range 8 {
 		wg.Go(func() {
-			key := VariantKey(fmt.Sprintf("aabbccdd01%02d", goroutine))
+			key := imagerequest.VariantKey(fmt.Sprintf("aabbccdd01%02d", goroutine))
 			content := []byte(key)
 
 			for range 20 {