Restrict permission check on repositories and fix some problems (#5314)

* fix units permission problems

* fix some bugs and merge LoadUnits to repoAssignment

* refactor permission struct and add some copyright heads

* remove unused codes

* fix routes units check

* improve permission check

* add unit tests for permission

* fix typo

* fix tests

* fix some routes

* fix api permission check

* improve permission check

* fix some permission check

* fix tests

* fix tests

* improve some permission check

* fix some permission check

* refactor AccessLevel

* fix bug

* fix tests

* fix tests

* fix tests

* fix AccessLevel

* rename CanAccess

* fix tests

* fix comment

* fix bug

* add missing unit for test repos

* fix bug

* rename some functions

* fix routes check

routers/api/v1/repo/release.go

@@ -122,10 +122,6 @@ func CreateRelease(ctx *context.APIContext, form api.CreateReleaseOption) {
 	// responses:
 	//   "201":
 	//     "$ref": "#/responses/Release"
-	if ctx.Repo.AccessMode < models.AccessModeWrite {
-		ctx.Status(403)
-		return
-	}
 	rel, err := models.GetRelease(ctx.Repo.Repository.ID, form.TagName)
 	if err != nil {
 		if !models.IsErrReleaseNotExist(err) {
@@ -209,10 +205,6 @@ func EditRelease(ctx *context.APIContext, form api.EditReleaseOption) {
 	// responses:
 	//   "200":
 	//     "$ref": "#/responses/Release"
-	if ctx.Repo.AccessMode < models.AccessModeWrite {
-		ctx.Status(403)
-		return
-	}
 	id := ctx.ParamsInt64(":id")
 	rel, err := models.GetReleaseByID(id)
 	if err != nil && !models.IsErrReleaseNotExist(err) {
@@ -285,10 +277,6 @@ func DeleteRelease(ctx *context.APIContext) {
 	// responses:
 	//   "204":
 	//     "$ref": "#/responses/empty"
-	if ctx.Repo.AccessMode < models.AccessModeWrite {
-		ctx.Status(403)
-		return
-	}
 	id := ctx.ParamsInt64(":id")
 	rel, err := models.GetReleaseByID(id)
 	if err != nil && !models.IsErrReleaseNotExist(err) {