grumble, pkg/acl: move ACL handling to the acl package.

pkg/acl/context.go

@@ -0,0 +1,48 @@
+// Copyright (c) 2010-2013 The Grumble Authors
+// The use of this source code is goverened by a BSD-style
+// license that can be found in the LICENSE-file.
+
+package acl
+
+// Context represents a context in which ACLs can
+// be understood. Typically embedded into a type
+// that represents a Mumble channel.
+type Context struct {
+	// Parent points to the context's parent.
+	// May be nil if the Context does not have a parent.
+	Parent      *Context
+
+	// ACLs is the Context's list of ACL entries.
+	ACLs        []ACL
+
+	// Groups is the Context's representation of groups.
+	// It is indexed by the Group's name.
+	Groups      map[string]Group
+
+	// InheritACL determines whether this context should
+	// inherit ACLs from its parent.
+	InheritACL  bool
+}
+
+// indexOf finds the index of the context ctx in the context chain contexts.
+// Returns -1 if the given context was not found in the context chain.
+func indexOf(contexts []*Context, ctx *Context) int {
+	for i, iter := range contexts {
+		if iter == ctx {
+			return i
+		}
+	}
+	return -1
+}
+
+// buildChain walks from the context ctx back through all of its parents,
+// collecting them all in a slice. The first element of the returned
+// slice is the final ancestor (it has a nil Parent).
+func buildChain(ctx *Context) []*Context {
+	chain := []*Context{}
+	for ctx != nil {
+		chain = append([]*Context{ctx}, chain...)
+		ctx = ctx.Parent
+	}
+	return chain
+}