| // 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 ( |
| goast "go/ast" |
| |
| "cuelang.org/go/cue/ast" |
| "cuelang.org/go/cue/build" |
| "cuelang.org/go/cue/errors" |
| "cuelang.org/go/internal" |
| ) |
| |
| // An Instance defines a single configuration based on a collection of |
| // underlying CUE files. |
| type Instance struct { |
| *index |
| |
| rootStruct *structLit // the struct to insert root values into |
| rootValue value // the value to evaluate: may add comprehensions |
| |
| // scope is used as an additional top-level scope between the package scope |
| // and the predeclared identifiers. |
| scope *structLit |
| |
| ImportPath string |
| Dir string |
| Name string |
| |
| Incomplete bool // true if Pkg and all its dependencies are free of errors |
| Err errors.Error // non-nil if the package had errors |
| |
| inst *build.Instance |
| |
| complete bool // for cycle detection |
| } |
| |
| func (x *index) addInst(p *Instance) *Instance { |
| if p.rootStruct == nil { |
| panic("struct must not be nil") |
| } |
| p.index = x |
| x.imports[p.rootStruct] = p |
| if p.ImportPath != "" { |
| x.importsByPath[p.ImportPath] = p |
| } |
| return p |
| } |
| |
| func (x *index) getImportFromNode(v value) *Instance { |
| imp := x.imports[v] |
| if imp == nil && x.parent != nil { |
| return x.parent.getImportFromNode(v) |
| } |
| return imp |
| } |
| |
| // newInstance creates a new instance. Use Insert to populate the instance. |
| func (x *index) newInstance(p *build.Instance) *Instance { |
| st := &structLit{baseValue: baseValue{nil}} |
| i := &Instance{ |
| rootStruct: st, |
| rootValue: st, |
| inst: p, |
| } |
| if p != nil { |
| i.ImportPath = p.ImportPath |
| i.Dir = p.Dir |
| i.Name = p.PkgName |
| if p.Err != nil { |
| i.setListOrError(p.Err) |
| } |
| } |
| return x.addInst(i) |
| } |
| |
| func (inst *Instance) setListOrError(err errors.Error) { |
| inst.Incomplete = true |
| inst.Err = errors.Append(inst.Err, err) |
| } |
| |
| func (inst *Instance) setError(err errors.Error) { |
| inst.Incomplete = true |
| inst.Err = errors.Append(inst.Err, err) |
| } |
| |
| func (inst *Instance) eval(ctx *context) evaluated { |
| // TODO: remove manifest here? |
| v := ctx.manifest(inst.rootValue) |
| if s, ok := v.(*structLit); ok && s.emit != nil { |
| return s.emit.evalPartial(ctx) |
| } |
| return v |
| } |
| |
| func init() { |
| internal.EvalExpr = func(value, expr interface{}) interface{} { |
| v := value.(Value) |
| e := expr.(ast.Expr) |
| ctx := v.idx.newContext() |
| return newValueRoot(ctx, evalExpr(v.idx, v.eval(ctx), e)) |
| } |
| } |
| |
| func evalExpr(idx *index, x value, expr ast.Expr) evaluated { |
| if isBottom(x) { |
| return idx.mkErr(x, "error evaluating instance: %v", x) |
| } |
| obj, ok := x.(*structLit) |
| if !ok { |
| return idx.mkErr(obj, "instance is not a struct") |
| } |
| |
| v := newVisitor(idx, nil, nil, obj) |
| return eval(idx, v.walk(expr)) |
| } |
| |
| func (inst *Instance) evalExpr(ctx *context, expr ast.Expr) evaluated { |
| root := inst.eval(ctx) |
| if isBottom(root) { |
| return ctx.mkErr(root, "error evaluating instance") |
| } |
| obj, ok := root.(*structLit) |
| if !ok { |
| return ctx.mkErr(obj, "instance is not a struct") |
| } |
| v := newVisitor(ctx.index, inst.inst, nil, obj) |
| return v.walk(expr).evalPartial(ctx) |
| } |
| |
| // Doc returns the package comments for this instance. |
| func (inst *Instance) Doc() []*ast.CommentGroup { |
| var docs []*ast.CommentGroup |
| if inst.inst == nil { |
| return nil |
| } |
| for _, f := range inst.inst.Files { |
| pkg, _, _ := internal.PackageInfo(f) |
| if pkg == nil { |
| continue |
| } |
| var cg *ast.CommentGroup |
| for _, c := range pkg.Comments() { |
| if c.Position == 0 { |
| cg = c |
| } |
| } |
| if cg != nil { |
| docs = append(docs, cg) |
| } |
| } |
| return docs |
| } |
| |
| // Value returns the root value of the configuration. If the configuration |
| // defines in emit value, it will be that value. Otherwise it will be all |
| // top-level values. |
| func (inst *Instance) Value() Value { |
| ctx := inst.newContext() |
| return newValueRoot(ctx, inst.eval(ctx)) |
| } |
| |
| // Eval evaluates an expression within an existing instance. |
| // |
| // Expressions may refer to builtin packages if they can be uniquely identified. |
| func (inst *Instance) Eval(expr ast.Expr) Value { |
| ctx := inst.newContext() |
| result := inst.evalExpr(ctx, expr) |
| return newValueRoot(ctx, result) |
| } |
| |
| // Merge unifies the given instances into a single one. |
| // |
| // Errors regarding conflicts are included in the result, but not reported, so |
| // that these will only surface during manifestation. This allows |
| // non-conflicting parts to be used. |
| func Merge(inst ...*Instance) *Instance { |
| switch len(inst) { |
| case 0: |
| return nil |
| case 1: |
| return inst[0] |
| } |
| |
| values := []value{} |
| for _, i := range inst { |
| if i.Err != nil { |
| return i |
| } |
| values = append(values, i.rootValue) |
| } |
| merged := &mergedValues{values: values} |
| |
| ctx := inst[0].newContext() |
| |
| st, ok := ctx.manifest(merged).(*structLit) |
| if !ok { |
| return nil |
| } |
| |
| p := ctx.index.addInst(&Instance{ |
| rootStruct: st, |
| rootValue: merged, |
| complete: true, |
| }) |
| return p |
| } |
| |
| // Build creates a new instance from the build instances, allowing unbound |
| // identifier to bind to the top-level field in inst. The top-level fields in |
| // inst take precedence over predeclared identifier and builtin functions. |
| func (inst *Instance) Build(p *build.Instance) *Instance { |
| p.Complete() |
| |
| idx := inst.index |
| |
| i := idx.newInstance(p) |
| if i.Err != nil { |
| return i |
| } |
| |
| ctx := inst.newContext() |
| val := newValueRoot(ctx, inst.rootValue) |
| v, err := val.structValFull(ctx) |
| if err != nil { |
| i.setError(val.toErr(err)) |
| return i |
| } |
| i.scope = v.n |
| |
| if err := resolveFiles(idx, p); err != nil { |
| i.setError(err) |
| return i |
| } |
| for _, f := range p.Files { |
| if err := i.insertFile(f); err != nil { |
| i.setListOrError(err) |
| } |
| } |
| i.complete = true |
| |
| return i |
| } |
| |
| // Lookup reports the value at a path starting from the top level struct (not |
| // the emitted value). The Exists method of the returned value will report false |
| // if the path did not exist. The Err method reports if any error occurred |
| // during evaluation. The empty path returns the top-level configuration struct, |
| // regardless of whether an emit value was specified. |
| func (inst *Instance) Lookup(path ...string) Value { |
| idx := inst.index |
| ctx := idx.newContext() |
| v := newValueRoot(ctx, inst.rootValue) |
| for _, k := range path { |
| obj, err := v.structValData(ctx) |
| if err != nil { |
| return Value{idx, &valueData{arc: arc{cache: err, v: err}}} |
| } |
| v = obj.Lookup(k) |
| } |
| return v |
| } |
| |
| // LookupField reports a Field at a path starting from v, or an error if the |
| // path is not. The empty path returns v itself. |
| // |
| // It cannot look up hidden or unexported fields. |
| func (inst *Instance) LookupField(path ...string) (f FieldInfo, err error) { |
| idx := inst.index |
| ctx := idx.newContext() |
| v := newValueRoot(ctx, inst.rootValue) |
| for i, k := range path { |
| s, err := v.Struct() |
| if err != nil { |
| return f, err |
| } |
| |
| f, err = s.FieldByName(k) |
| if err != nil { |
| return f, err |
| } |
| if f.IsHidden || (i == 0 || f.IsDefinition) && !goast.IsExported(f.Name) { |
| return f, errNotFound |
| } |
| } |
| return f, err |
| } |
| |
| // Fill creates a new instance with the values of the old instance unified with |
| // the given value. It is not possible to update the emit value. |
| func (inst *Instance) Fill(x interface{}, path ...string) (*Instance, error) { |
| ctx := inst.newContext() |
| root := ctx.manifest(inst.rootValue) |
| for i := len(path) - 1; i >= 0; i-- { |
| x = map[string]interface{}{path[i]: x} |
| } |
| value := convert(ctx, root, true, x) |
| eval := binOp(ctx, baseValue{}, opUnify, root, value) |
| // TODO: validate recursively? |
| err := inst.Err |
| var st *structLit |
| switch x := eval.(type) { |
| case *structLit: |
| st = x |
| default: |
| // This should not happen. |
| err = errors.Newf(x.Pos(), "error filling struct") |
| case *bottom: |
| err = inst.Value().toErr(x) |
| } |
| inst = inst.index.addInst(&Instance{ |
| rootStruct: st, |
| rootValue: st, |
| inst: nil, |
| |
| // TODO: somehow indicate this is not an original |
| ImportPath: inst.ImportPath, |
| Name: inst.Name, |
| Incomplete: inst.Incomplete, |
| Err: err, |
| |
| complete: err != nil, |
| }) |
| return inst, err |
| } |