environs: simplify EnvironProvider interface.

environs/ec2/util.go

Index: environs/ec2/util.go
=== modified file 'environs/ec2/util.go'
--- environs/ec2/util.go	2012-03-12 18:04:37 +0000
+++ environs/ec2/util.go	2012-05-17 08:58:09 +0000
@@ -1,48 +1,9 @@
 package ec2
 
 import (
-	"launchpad.net/juju/go/schema"
 	"time"
 )
 
-// this stuff could/should be in the schema package.
-
-// checkerFunc defines a schema.Checker using a function that
-// implements scheme.Checker.Coerce.
-type checkerFunc func(v interface{}, path []string) (newv interface{}, err error)
-
-func (f checkerFunc) Coerce(v interface{}, path []string) (newv interface{}, err error) {
-	return f(v, path)
-}
-
-// combineCheckers returns a Checker that checks a value by passing it
-// through the "pipeline" defined by checkers. When the returned checker's
-// Coerce method is called on a value, the value is passed through the
-// first checker in checkers; the resulting value is used as input to the
-// next checker, and so on.
-func combineCheckers(checkers ...schema.Checker) schema.Checker {
-	f := func(v interface{}, path []string) (newv interface{}, err error) {
-		for _, c := range checkers {
-			v, err = c.Coerce(v, path)
-			if err != nil {
-				return nil, err
-			}
-		}
-		return v, nil
-	}
-	return checkerFunc(f)
-}
-
-// oneOf(a, b, c) is equivalent to (but less verbose than):
-// schema.OneOf(schema.Const(a), schema.Const(b), schema.Const(c))
-func oneOf(values ...interface{}) schema.Checker {
-	c := make([]schema.Checker, len(values))
-	for i, v := range values {
-		c[i] = schema.Const(v)
-	}
-	return schema.OneOf(c...)
-}
-
 // attemptStrategy represents a strategy for waiting for an ec2 request
 // to complete successfully.  
 //