feat: use hashed uses string as cache dir name (#186)

Port of https://gitea.com/gitea/act/pulls/117

Refs forgejo/act#100

Co-authored-by: Jason Song <i@wolfogre.com>
Reviewed-on: https://code.forgejo.org/forgejo/act/pulls/186
Reviewed-by: Michael Kriese <michael.kriese@gmx.de>

act/model/workflow.go

@@ -1,9 +1,12 @@
 package model
 
 import (
+	"crypto/sha256"
+	"encoding/hex"
 	"errors"
 	"fmt"
 	"io"
+	"path/filepath"
 	"reflect"
 	"regexp"
 	"strconv"
@@ -734,6 +737,12 @@ func (s *Step) Type() StepType {
 	return StepTypeUsesActionRemote
 }
 
+func (s *Step) UsesHash() string {
+	hashBytes := sha256.Sum256([]byte(s.Uses))
+	hashString := hex.EncodeToString(hashBytes[:])
+	return filepath.Join(hashString[:2], hashString[2:])
+}
+
 // ReadWorkflow returns a list of jobs for a given workflow file reader
 func ReadWorkflow(in io.Reader, validate bool) (*Workflow, error) {
 	if validate {

act/model/workflow_test.go

@@ -668,3 +668,37 @@ func TestReadWorkflow_WorkflowDispatchConfig(t *testing.T) {
 		Type:     "choice",
 	}, workflowDispatch.Inputs["logLevel"])
 }
+
+func TestStepUsesHash(t *testing.T) {
+	type fields struct {
+		Uses string
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		want   string
+	}{
+		{
+			name: "regular",
+			fields: fields{
+				Uses: "https://example.com/testa/testb@v3",
+			},
+			want: "e6/d70c1e8a4cc1e1cb02e32b3b60cc8dff319bb4fe5832fbc8b800711f18e7a2",
+		},
+		{
+			name: "empty",
+			fields: fields{
+				Uses: "",
+			},
+			want: "e3/b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			s := &Step{
+				Uses: tt.fields.Uses,
+			}
+			assert.Equalf(t, tt.want, s.UsesHash(), "UsesHash()")
+		})
+	}
+}