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// Copyright 2018 The CUE Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package cue
import (
"strings"
"sync"
"cuelang.org/go/cue/ast"
"cuelang.org/go/cue/ast/astutil"
"cuelang.org/go/cue/build"
"cuelang.org/go/cue/errors"
"cuelang.org/go/cue/token"
"cuelang.org/go/internal"
"cuelang.org/go/internal/core/adt"
"cuelang.org/go/internal/core/compile"
"cuelang.org/go/internal/core/runtime"
)
// A Runtime is used for creating CUE interpretations.
//
// Any operation that involves two Values or Instances should originate from
// the same Runtime.
//
// The zero value of a Runtime is ready to use.
type Runtime struct {
ctx *build.Context // TODO: remove
idx *index
}
func init() {
internal.GetRuntimeNew = func(instance interface{}) interface{} {
switch x := instance.(type) {
case Value:
return &Runtime{idx: x.idx}
case *Instance:
return &Runtime{idx: x.index}
default:
panic("argument must be Value or *Instance")
}
}
internal.CheckAndForkRuntimeNew = func(runtime, value interface{}) interface{} {
r := runtime.(*Runtime)
idx := value.(Value).ctx().index
if idx != r.idx {
panic("value not from same runtime")
}
return &Runtime{idx: newIndex(idx)}
}
internal.CoreValue = func(value interface{}) (runtime, vertex interface{}) {
if v, ok := value.(Value); ok && v.v != nil {
return v.idx.Index, v.v
}
return nil, nil
}
}
func dummyLoad(token.Pos, string) *build.Instance { return nil }
func (r *Runtime) index() *index {
if r.idx == nil {
r.idx = newIndex(sharedIndex)
}
return r.idx
}
func (r *Runtime) buildContext() *build.Context {
ctx := r.ctx
if r.ctx == nil {
ctx = build.NewContext()
}
return ctx
}
func (r *Runtime) complete(p *build.Instance) (*Instance, error) {
idx := r.index()
if err := p.Complete(); err != nil {
return nil, err
}
inst := idx.loadInstance(p)
inst.ImportPath = p.ImportPath
if inst.Err != nil {
return nil, inst.Err
}
return inst, nil
}
// Compile compiles the given source into an Instance. The source code may be
// provided as a string, byte slice, io.Reader. The name is used as the file
// name in position information. The source may import builtin packages. Use
// Build to allow importing non-builtin packages.
func (r *Runtime) Compile(filename string, source interface{}) (*Instance, error) {
ctx := r.buildContext()
p := ctx.NewInstance(filename, dummyLoad)
if err := p.AddFile(filename, source); err != nil {
return nil, p.Err
}
return r.complete(p)
}
// CompileFile compiles the given source file into an Instance. The source may
// import builtin packages. Use Build to allow importing non-builtin packages.
func (r *Runtime) CompileFile(file *ast.File) (*Instance, error) {
ctx := r.buildContext()
p := ctx.NewInstance(file.Filename, dummyLoad)
err := p.AddSyntax(file)
if err != nil {
return nil, err
}
_, p.PkgName, _ = internal.PackageInfo(file)
return r.complete(p)
}
// CompileExpr compiles the given source expression into an Instance. The source
// may import builtin packages. Use Build to allow importing non-builtin
// packages.
func (r *Runtime) CompileExpr(expr ast.Expr) (*Instance, error) {
f, err := astutil.ToFile(expr)
if err != nil {
return nil, err
}
return r.CompileFile(f)
}
// Parse parses a CUE source value into a CUE Instance. The source code may
// be provided as a string, byte slice, or io.Reader. The name is used as the
// file name in position information. The source may import builtin packages.
//
// Deprecated: use Compile
func (r *Runtime) Parse(name string, source interface{}) (*Instance, error) {
return r.Compile(name, source)
}
// Build creates an Instance from the given build.Instance. A returned Instance
// may be incomplete, in which case its Err field is set.
func (r *Runtime) Build(instance *build.Instance) (*Instance, error) {
return r.complete(instance)
}
// Build creates one Instance for each build.Instance. A returned Instance
// may be incomplete, in which case its Err field is set.
//
// Example:
// inst := cue.Build(load.Instances(args))
//
func Build(instances []*build.Instance) []*Instance {
if len(instances) == 0 {
panic("cue: list of instances must not be empty")
}
var r Runtime
a, _ := r.build(instances)
return a
}
func (r *Runtime) build(instances []*build.Instance) ([]*Instance, error) {
index := r.index()
loaded := []*Instance{}
var errs errors.Error
for _, p := range instances {
_ = p.Complete()
errs = errors.Append(errs, p.Err)
i := index.loadInstance(p)
errs = errors.Append(errs, i.Err)
loaded = append(loaded, i)
}
// TODO: insert imports
return loaded, errs
}
// FromExpr creates an instance from an expression.
// Any references must be resolved beforehand.
//
// Deprecated: use CompileExpr
func (r *Runtime) FromExpr(expr ast.Expr) (*Instance, error) {
return r.CompileFile(&ast.File{
Decls: []ast.Decl{&ast.EmbedDecl{Expr: expr}},
})
}
// index maps conversions from label names to internal codes.
//
// All instances belonging to the same package should share this index.
type index struct {
adt.Runtime
*runtime.Index
loaded map[*build.Instance]*Instance
mutex sync.Mutex
}
// sharedIndex is used for indexing builtins and any other labels common to
// all instances.
var sharedIndex = &index{
Runtime: runtime.SharedRuntimeNew,
Index: runtime.SharedIndexNew,
loaded: map[*build.Instance]*Instance{},
}
// NewRuntime creates a *runtime.Runtime with builtins preloaded.
func NewRuntime() *runtime.Runtime {
idx := runtime.NewIndex(sharedIndex.Index)
r := runtime.NewWithIndex(idx)
i := &index{
Runtime: r,
Index: idx,
loaded: map[*build.Instance]*Instance{},
}
r.Data = i
return r
}
// newIndex creates a new index.
func newIndex(parent *index) *index {
idx := runtime.NewIndex(parent.Index)
r := runtime.NewWithIndex(idx)
i := &index{
Runtime: r,
Index: idx,
loaded: map[*build.Instance]*Instance{},
}
r.Data = i
return i
}
func isBuiltin(s string) bool {
_, ok := builtins[s]
return ok
}
func (idx *index) loadInstance(p *build.Instance) *Instance {
_ = visitInstances(p, func(p *build.Instance, errs errors.Error) errors.Error {
if inst := idx.loaded[p]; inst != nil {
if !inst.complete {
// cycles should be detected by the builder and it should not be
// possible to construct a build.Instance that has them.
panic("cue: cycle")
}
return inst.Err
}
err := runtime.ResolveFiles(idx.Index, p, isBuiltin)
errs = errors.Append(errs, err)
v, err := compile.Files(nil, idx.Runtime, p.Files...)
errs = errors.Append(errs, err)
inst := newInstance(idx, p, v)
idx.loaded[p] = inst
inst.Err = errs
inst.ImportPath = p.ImportPath
inst.complete = true
return inst.Err
})
return idx.loaded[p]
}
// TODO: runtime.Runtime has a similar, much simpler, implementation. This
// code should go.
type visitFunc func(b *build.Instance, err errors.Error) (errs errors.Error)
// visitInstances calls f for each transitive dependency.
//
// It passes any errors that occur in transitive dependencies to the visitFunc.
// visitFunc must return the errors it is passed or return nil to ignore it.
func visitInstances(b *build.Instance, f visitFunc) (errs errors.Error) {
v := visitor{b: b, f: f, errs: b.Err}
for _, file := range b.Files {
v.file(file)
}
return v.f(b, v.errs)
}
type visitor struct {
b *build.Instance
f visitFunc
errs errors.Error
}
func (v *visitor) addErr(e errors.Error) {
v.errs = errors.Append(v.errs, e)
}
func (v *visitor) file(file *ast.File) {
file.VisitImports(func(x *ast.ImportDecl) {
for _, s := range x.Specs {
v.spec(s)
}
})
}
func (v *visitor) spec(spec *ast.ImportSpec) {
info, err := astutil.ParseImportSpec(spec)
if err != nil {
v.addErr(errors.Promote(err, "invalid import path"))
return
}
pkg := v.b.LookupImport(info.ID)
if pkg == nil {
if strings.Contains(info.ID, ".") {
v.addErr(errors.Newf(spec.Pos(),
"package %q imported but not defined in %s",
info.ID, v.b.ImportPath))
}
return
}
v.addErr(visitInstances(pkg, v.f))
}