Files
mgmt/lang/funcs/lookup_default_func.go
James Shubin 3e31ee9455 legal: Additional permission under GNU GPL version 3 section 7
With the recent merging of embedded package imports and the entry CLI
package, it is now possible for users to build in mcl code into a single
binary. This additional permission makes it explicitly clear that this
is permitted to make it easier for those users. The condition is phrased
so that the terms can be "patched" by the original author if it's
necessary for the project. For example, if the name of the language
(mcl) changes, has a differently named new version, someone finds a
phrasing improvement or a legal loophole, or for some other
reasonable circumstance. Now go write some beautiful embedded tools!
2024-03-05 01:04:09 -05:00

555 lines
16 KiB
Go

// Mgmt
// Copyright (C) 2013-2024+ James Shubin and the project contributors
// Written by James Shubin <james@shubin.ca> and the project contributors
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
// Additional permission under GNU GPL version 3 section 7
//
// If you modify this program, or any covered work, by linking or combining it
// with embedded mcl code and modules (and that the embedded mcl code and
// modules which link with this program, contain a copy of their source code in
// the authoritative form) containing parts covered by the terms of any other
// license, the licensors of this program grant you additional permission to
// convey the resulting work. Furthermore, the licensors of this program grant
// the original author, James Shubin, additional permission to update this
// additional permission if he deems it necessary to achieve the goals of this
// additional permission.
package funcs
import (
"context"
"fmt"
"github.com/purpleidea/mgmt/lang/interfaces"
"github.com/purpleidea/mgmt/lang/types"
"github.com/purpleidea/mgmt/util/errwrap"
)
const (
// LookupDefaultFuncName is the name this function is registered as.
// This starts with an underscore so that it cannot be used from the
// lexer.
LookupDefaultFuncName = "_lookup_default"
// arg names...
lookupDefaultArgNameListOrMap = "listormap"
lookupDefaultArgNameIndexOrKey = "indexorkey"
lookupDefaultArgNameDefault = "default"
)
func init() {
Register(LookupDefaultFuncName, func() interfaces.Func { return &LookupDefaultFunc{} }) // must register the func and name
}
var _ interfaces.PolyFunc = &LookupDefaultFunc{} // ensure it meets this expectation
// LookupDefaultFunc is a list index or map key lookup function. It does both
// because the current syntax in the parser is identical, so it's convenient to
// mix the two together. This calls out to some of the code in the
// ListLookupDefaultFunc and MapLookupDefaultFunc implementations. If the index
// or key for this input doesn't exist, then it will return the default value
// you specified for this function.
type LookupDefaultFunc struct {
Type *types.Type // Kind == List OR Map, that is used as the list/map we lookup in
//init *interfaces.Init
fn interfaces.PolyFunc // handle to ListLookupDefaultFunc or MapLookupDefaultFunc
}
// String returns a simple name for this function. This is needed so this struct
// can satisfy the pgraph.Vertex interface.
func (obj *LookupDefaultFunc) String() string {
return LookupDefaultFuncName
}
// ArgGen returns the Nth arg name for this function.
func (obj *LookupDefaultFunc) ArgGen(index int) (string, error) {
seq := []string{lookupDefaultArgNameListOrMap, lookupDefaultArgNameIndexOrKey, lookupDefaultArgNameDefault}
if l := len(seq); index >= l {
return "", fmt.Errorf("index %d exceeds arg length of %d", index, l)
}
return seq[index], nil
}
// Unify returns the list of invariants that this func produces.
func (obj *LookupDefaultFunc) Unify(expr interfaces.Expr) ([]interfaces.Invariant, error) {
var invariants []interfaces.Invariant
var invar interfaces.Invariant
// func(list T1, index int, default T3) T3
// (list: []T3 => T3 aka T1 => T3)
// OR
// func(map T1, key T2, default T3) T3
// (map: T2 => T3)
listOrMapName, err := obj.ArgGen(0)
if err != nil {
return nil, err
}
indexOrKeyName, err := obj.ArgGen(1)
if err != nil {
return nil, err
}
defaultName, err := obj.ArgGen(2)
if err != nil {
return nil, err
}
dummyListOrMap := &interfaces.ExprAny{} // corresponds to the list or map type
dummyIndexOrKey := &interfaces.ExprAny{} // corresponds to the index or key type
dummyDefault := &interfaces.ExprAny{} // corresponds to the default type
dummyOut := &interfaces.ExprAny{} // corresponds to the out string
// default type and out are the same
invar = &interfaces.EqualityInvariant{
Expr1: dummyDefault,
Expr2: dummyOut,
}
invariants = append(invariants, invar)
ors := []interfaces.Invariant{} // solve only one from this list
var listInvariants []interfaces.Invariant
// relationship between T1 and T3
invar = &interfaces.EqualityWrapListInvariant{
Expr1: dummyListOrMap,
Expr2Val: dummyDefault,
}
listInvariants = append(listInvariants, invar)
// the index has to be an int
invar = &interfaces.EqualsInvariant{
Expr: dummyIndexOrKey,
Type: types.TypeInt,
}
listInvariants = append(listInvariants, invar)
// all of these need to be true together
and := &interfaces.ConjunctionInvariant{
Invariants: listInvariants,
}
ors = append(ors, and) // one solution added!
// OR
// relationship between T1, T2 and T3
mapInvariant := &interfaces.EqualityWrapMapInvariant{
Expr1: dummyListOrMap,
Expr2Key: dummyIndexOrKey,
Expr2Val: dummyDefault,
}
ors = append(ors, mapInvariant) // one solution added!
invar = &interfaces.ExclusiveInvariant{
Invariants: ors, // one and only one of these should be true
}
invariants = append(invariants, invar)
// full function
mapped := make(map[string]interfaces.Expr)
ordered := []string{listOrMapName, indexOrKeyName, defaultName}
mapped[listOrMapName] = dummyListOrMap
mapped[indexOrKeyName] = dummyIndexOrKey
mapped[defaultName] = dummyDefault
invar = &interfaces.EqualityWrapFuncInvariant{
Expr1: expr, // maps directly to us!
Expr2Map: mapped,
Expr2Ord: ordered,
Expr2Out: dummyOut,
}
invariants = append(invariants, invar)
// generator function
fn := func(fnInvariants []interfaces.Invariant, solved map[interfaces.Expr]*types.Type) ([]interfaces.Invariant, error) {
for _, invariant := range fnInvariants {
// search for this special type of invariant
cfavInvar, ok := invariant.(*interfaces.CallFuncArgsValueInvariant)
if !ok {
continue
}
// did we find the mapping from us to ExprCall ?
if cfavInvar.Func != expr {
continue
}
// cfavInvar.Expr is the ExprCall! (the return pointer)
// cfavInvar.Args are the args that ExprCall uses!
if l := len(cfavInvar.Args); l != 3 {
return nil, fmt.Errorf("unable to build function with %d args", l)
}
var invariants []interfaces.Invariant
var invar interfaces.Invariant
// add the relationship to the returned value
invar = &interfaces.EqualityInvariant{
Expr1: cfavInvar.Expr,
Expr2: dummyOut,
}
invariants = append(invariants, invar)
// add the relationships to the called args
invar = &interfaces.EqualityInvariant{
Expr1: cfavInvar.Args[0],
Expr2: dummyListOrMap,
}
invariants = append(invariants, invar)
invar = &interfaces.EqualityInvariant{
Expr1: cfavInvar.Args[1],
Expr2: dummyIndexOrKey,
}
invariants = append(invariants, invar)
invar = &interfaces.EqualityInvariant{
Expr1: cfavInvar.Args[2],
Expr2: dummyDefault,
}
invariants = append(invariants, invar)
// If we figure out all of these types, we'll know the
// full type...
var t1 *types.Type // list or map type
var t2 *types.Type // list or map index/key type
var t3 *types.Type // list or map val type
// validateArg0 checks: list or map T1
validateArg0 := func(typ *types.Type) error {
if typ == nil { // unknown so far
return nil
}
// we happen to have a list or a map!
if k := typ.Kind; k != types.KindList && k != types.KindMap {
return fmt.Errorf("unable to build function with 0th arg of kind: %s", k)
}
//isList := typ.Kind == types.KindList
isMap := typ.Kind == types.KindMap
if isMap && typ.Key == nil {
// programming error
return fmt.Errorf("map is missing type")
}
if typ.Val == nil { // used for list or map
// programming error
return fmt.Errorf("map/list is missing type")
}
if err := typ.Cmp(t1); t1 != nil && err != nil {
return errwrap.Wrapf(err, "input type was inconsistent")
}
if isMap {
if err := typ.Key.Cmp(t2); t2 != nil && err != nil {
return errwrap.Wrapf(err, "input key type was inconsistent")
}
}
if err := typ.Val.Cmp(t3); t3 != nil && err != nil {
return errwrap.Wrapf(err, "input val type was inconsistent")
}
// learn!
t1 = typ
if isMap {
t2 = typ.Key
} else if t1 != nil && t3 != nil {
t2 = types.TypeInt
}
t3 = typ.Val
return nil
}
// validateArg1 checks: list index
validateListArg1 := func(typ *types.Type) error {
if typ == nil { // unknown so far
return nil
}
if typ.Kind != types.KindInt {
return errwrap.Wrapf(err, "input index type was inconsistent")
}
// learn!
t2 = typ
return nil
}
// validateArg1 checks: map key T2
validateMapArg1 := func(typ *types.Type) error {
if typ == nil { // unknown so far
return nil
}
if err := typ.Cmp(t2); t2 != nil && err != nil {
return errwrap.Wrapf(err, "input key type was inconsistent")
}
if t1 != nil {
if err := typ.Cmp(t1.Key); err != nil {
return errwrap.Wrapf(err, "input key type was inconsistent")
}
}
if t3 != nil {
t := &types.Type{ // build t1
Kind: types.KindMap,
Key: typ, // t2
Val: t3,
}
if err := t.Cmp(t1); t1 != nil && err != nil {
return errwrap.Wrapf(err, "input type was inconsistent")
}
t1 = t // learn!
}
// learn!
t2 = typ
return nil
}
// validateArg1 checks: list index
validateArg1 := func(typ *types.Type) error {
if typ == nil { // unknown so far
return nil
}
isList := typ.Kind == types.KindList
isMap := typ.Kind == types.KindMap
if isList {
return validateListArg1(typ)
}
if isMap {
return validateMapArg1(typ)
}
return nil
}
// validateArg2 checks: list or map val T3
validateArg2 := func(typ *types.Type) error {
if typ == nil { // unknown so far
return nil
}
if err := typ.Cmp(t3); t3 != nil && err != nil {
return errwrap.Wrapf(err, "input val type was inconsistent")
}
if t1 != nil {
if err := typ.Cmp(t1.Val); err != nil {
return errwrap.Wrapf(err, "input val type was inconsistent")
}
}
isList := typ.Kind == types.KindList
isMap := typ.Kind == types.KindMap
if isMap && t2 != nil {
t := &types.Type{ // build t1
Kind: types.KindMap,
Key: t2,
Val: typ, // t3
}
if err := t.Cmp(t1); t1 != nil && err != nil {
return errwrap.Wrapf(err, "input type was inconsistent")
}
t1 = t // learn!
}
t := &types.Type{ // build t1 (for lists)
Kind: types.KindList,
Val: typ, // t3
}
if isList && t3 != nil {
if err := t.Cmp(t1); t1 != nil && err != nil {
return errwrap.Wrapf(err, "input type was inconsistent")
}
//t1 = t // learn!
}
// learn!
if isList {
t1 = t
if t1 != nil && t3 != nil {
t2 = types.TypeInt
}
}
t3 = typ
return nil
}
if typ, err := cfavInvar.Args[0].Type(); err == nil { // is it known?
// this sets t1 and t3 on success (and sometimes t2) if it learned
if err := validateArg0(typ); err != nil {
return nil, errwrap.Wrapf(err, "first arg type is inconsistent")
}
}
if typ, exists := solved[cfavInvar.Args[0]]; exists { // alternate way to lookup type
// this sets t1 and t3 on success (and sometimes t2) if it learned
if err := validateArg0(typ); err != nil {
return nil, errwrap.Wrapf(err, "first arg type is inconsistent")
}
}
if typ, err := cfavInvar.Args[1].Type(); err == nil { // is it known?
// this sets t2 (and sometimes t1) on success if it learned
if err := validateArg1(typ); err != nil {
return nil, errwrap.Wrapf(err, "second arg type is inconsistent")
}
}
if typ, exists := solved[cfavInvar.Args[1]]; exists { // alternate way to lookup type
// this sets t2 (and sometimes t1) on success if it learned
if err := validateArg1(typ); err != nil {
return nil, errwrap.Wrapf(err, "second arg type is inconsistent")
}
}
if typ, err := cfavInvar.Args[2].Type(); err == nil { // is it known?
// this sets t3 (and sometimes t1 (and sometimes t2)) on success if it learned
if err := validateArg2(typ); err != nil {
return nil, errwrap.Wrapf(err, "third default arg type is inconsistent")
}
}
if typ, exists := solved[cfavInvar.Args[2]]; exists { // alternate way to lookup type
// this sets t3 (and sometimes t1 (and sometimes t2)) on success if it learned
if err := validateArg2(typ); err != nil {
return nil, errwrap.Wrapf(err, "third default arg type is inconsistent")
}
}
// XXX: if the types aren't know statically?
if t1 != nil {
invar := &interfaces.EqualsInvariant{
Expr: dummyListOrMap,
Type: t1,
}
invariants = append(invariants, invar)
}
if t2 != nil {
invar := &interfaces.EqualsInvariant{
Expr: dummyIndexOrKey,
Type: t2,
}
invariants = append(invariants, invar)
}
if t3 != nil {
invar := &interfaces.EqualsInvariant{
Expr: dummyDefault,
Type: t3,
}
invariants = append(invariants, invar)
}
// XXX: if t{1..2} are missing, we could also return a
// new generator for later if we learn new information,
// but we'd have to be careful to not do it infinitely.
// TODO: do we return this relationship with ExprCall?
invar = &interfaces.EqualityWrapCallInvariant{
// TODO: should Expr1 and Expr2 be reversed???
Expr1: cfavInvar.Expr,
//Expr2Func: cfavInvar.Func, // same as below
Expr2Func: expr,
}
invariants = append(invariants, invar)
// TODO: are there any other invariants we should build?
return invariants, nil // generator return
}
// We couldn't tell the solver anything it didn't already know!
return nil, fmt.Errorf("couldn't generate new invariants")
}
invar = &interfaces.GeneratorInvariant{
Func: fn,
}
invariants = append(invariants, invar)
return invariants, nil
}
// Build is run to turn the polymorphic, undetermined function, into the
// specific statically typed version. It is usually run after Unify completes,
// and must be run before Info() and any of the other Func interface methods are
// used. This function is idempotent, as long as the arg isn't changed between
// runs.
func (obj *LookupDefaultFunc) Build(typ *types.Type) (*types.Type, error) {
// typ is the KindFunc signature we're trying to build...
if typ.Kind != types.KindFunc {
return nil, fmt.Errorf("input type must be of kind func")
}
if len(typ.Ord) < 1 {
return nil, fmt.Errorf("the lookup function needs at least one arg") // actually 2 or 3
}
tListOrMap, exists := typ.Map[typ.Ord[0]]
if !exists || tListOrMap == nil {
return nil, fmt.Errorf("first arg must be specified")
}
if tListOrMap == nil {
return nil, fmt.Errorf("first arg must have a type")
}
if tListOrMap.Kind == types.KindList {
obj.fn = &ListLookupDefaultFunc{} // set it
return obj.fn.Build(typ)
}
if tListOrMap.Kind == types.KindMap {
obj.fn = &MapLookupDefaultFunc{} // set it
return obj.fn.Build(typ)
}
return nil, fmt.Errorf("we must lookup from either a list or a map")
}
// Validate tells us if the input struct takes a valid form.
func (obj *LookupDefaultFunc) Validate() error {
if obj.fn == nil { // build must be run first
return fmt.Errorf("type is still unspecified")
}
return obj.fn.Validate()
}
// Info returns some static info about itself. Build must be called before this
// will return correct data.
func (obj *LookupDefaultFunc) Info() *interfaces.Info {
if obj.fn == nil {
return &interfaces.Info{
Pure: true,
Memo: false,
Sig: nil, // func kind
Err: obj.Validate(),
}
}
return obj.fn.Info()
}
// Init runs some startup code for this function.
func (obj *LookupDefaultFunc) Init(init *interfaces.Init) error {
if obj.fn == nil {
return fmt.Errorf("function not built correctly")
}
//obj.init = init
return obj.fn.Init(init)
}
// Stream returns the changing values that this func has over time.
func (obj *LookupDefaultFunc) Stream(ctx context.Context) error {
if obj.fn == nil {
return fmt.Errorf("function not built correctly")
}
return obj.fn.Stream(ctx)
}