Image resource refactor

This commit pulls most of the image related logic into its own package, to make it easier to reason about and extend.

This is also a rewrite of the transformation logic used in Hugo Pipes, mostly to allow constructs like the one below:

    {{ ($myimg | fingerprint ).Width }}

Fixes #5903
Fixes #6234
Fixes #6266

1 files changed, 12 insertions, 10 deletions

diff --git a/tpl/resources/resources.go b/tpl/resources/resources.go
index 3d688e21c..e676a3412 100644
--- a/tpl/resources/resources.go
+++ b/tpl/resources/resources.go
@@ -22,7 +22,9 @@ import (
 	_errors "github.com/pkg/errors"
 
 	"github.com/gohugoio/hugo/deps"
+	"github.com/gohugoio/hugo/resources"
 	"github.com/gohugoio/hugo/resources/resource"
+
 	"github.com/gohugoio/hugo/resources/resource_factories/bundler"
 	"github.com/gohugoio/hugo/resources/resource_factories/create"
 	"github.com/gohugoio/hugo/resources/resource_transformers/integrity"
@@ -174,7 +176,7 @@ func (ns *Namespace) ExecuteAsTemplate(args ...interface{}) (resource.Resource,
 	}
 	data := args[1]
 
-	r, ok := args[2].(resource.Resource)
+	r, ok := args[2].(resources.ResourceTransformer)
 	if !ok {
 		return nil, fmt.Errorf("type %T not supported in Resource transformations", args[2])
 	}
@@ -201,9 +203,9 @@ func (ns *Namespace) Fingerprint(args ...interface{}) (resource.Resource, error)
 		}
 	}
 
-	r, ok := args[resIdx].(resource.Resource)
+	r, ok := args[resIdx].(resources.ResourceTransformer)
 	if !ok {
-		return nil, fmt.Errorf("%T is not a Resource", args[resIdx])
+		return nil, fmt.Errorf("%T can not be transformed", args[resIdx])
 	}
 
 	return ns.integrityClient.Fingerprint(r, algo)
@@ -211,7 +213,7 @@ func (ns *Namespace) Fingerprint(args ...interface{}) (resource.Resource, error)
 
 // Minify minifies the given Resource using the MediaType to pick the correct
 // minifier.
-func (ns *Namespace) Minify(r resource.Resource) (resource.Resource, error) {
+func (ns *Namespace) Minify(r resources.ResourceTransformer) (resource.Resource, error) {
 	return ns.minifyClient.Minify(r)
 }
 
@@ -219,7 +221,7 @@ func (ns *Namespace) Minify(r resource.Resource) (resource.Resource, error) {
 // object or a target path (string) as first argument.
 func (ns *Namespace) ToCSS(args ...interface{}) (resource.Resource, error) {
 	var (
-		r          resource.Resource
+		r          resources.ResourceTransformer
 		m          map[string]interface{}
 		targetPath string
 		err        error
@@ -266,7 +268,7 @@ func (ns *Namespace) PostCSS(args ...interface{}) (resource.Resource, error) {
 }
 
 // We allow string or a map as the first argument in some cases.
-func (ns *Namespace) resolveIfFirstArgIsString(args []interface{}) (resource.Resource, string, bool) {
+func (ns *Namespace) resolveIfFirstArgIsString(args []interface{}) (resources.ResourceTransformer, string, bool) {
 	if len(args) != 2 {
 		return nil, "", false
 	}
@@ -275,26 +277,26 @@ func (ns *Namespace) resolveIfFirstArgIsString(args []interface{}) (resource.Res
 	if !ok1 {
 		return nil, "", false
 	}
-	v2, ok2 := args[1].(resource.Resource)
+	v2, ok2 := args[1].(resources.ResourceTransformer)
 
 	return v2, v1, ok2
 }
 
 // This roundabout way of doing it is needed to get both pipeline behaviour and options as arguments.
-func (ns *Namespace) resolveArgs(args []interface{}) (resource.Resource, map[string]interface{}, error) {
+func (ns *Namespace) resolveArgs(args []interface{}) (resources.ResourceTransformer, map[string]interface{}, error) {
 	if len(args) == 0 {
 		return nil, nil, errors.New("no Resource provided in transformation")
 	}
 
 	if len(args) == 1 {
-		r, ok := args[0].(resource.Resource)
+		r, ok := args[0].(resources.ResourceTransformer)
 		if !ok {
 			return nil, nil, fmt.Errorf("type %T not supported in Resource transformations", args[0])
 		}
 		return r, nil, nil
 	}
 
-	r, ok := args[1].(resource.Resource)
+	r, ok := args[1].(resources.ResourceTransformer)
 	if !ok {
 		return nil, nil, fmt.Errorf("type %T not supported in Resource transformations", args[0])
 	}