Golang value.NewScopeValue函數代碼示例

/*
Qualify all identifiers for the parent expression. Checks for
duplicate aliases.
*/
func (this *KeyspaceTerm) Formalize(parent *expression.Formalizer) (f *expression.Formalizer, err error) {
	keyspace := this.Alias()
	if keyspace == "" {
		err = errors.NewNoTermNameError("FROM", "plan.keyspace.requires_name_or_alias")
		return
	}

	if this.keys != nil {
		_, err = this.keys.Accept(parent)
		if err != nil {
			return
		}
	}

	_, ok := parent.Allowed.Field(keyspace)
	if ok {
		err = errors.NewDuplicateAliasError("subquery", keyspace, "plan.keyspace.duplicate_alias")
		return nil, err
	}

	allowed := value.NewScopeValue(make(map[string]interface{}), parent.Allowed)
	allowed.SetField(keyspace, keyspace)

	f = expression.NewFormalizer()
	f.Keyspace = keyspace
	f.Allowed = allowed
	return
}

func buildFor(f *algebra.UpdateFor, val value.Value, arrays []value.Value, context *Context) ([]value.Value, error) {
	n := -1
	for _, a := range arrays {
		act := a.Actual()
		switch act := act.(type) {
		case []interface{}:
			if n < 0 || len(act) < n {
				n = len(act)
			}
		}
	}

	if n < 0 {
		return nil, nil
	}

	rv := make([]value.Value, n)
	for i, _ := range rv {
		rv[i] = value.NewScopeValue(make(map[string]interface{}, len(f.Bindings())), val)
		for j, b := range f.Bindings() {
			v, ok := arrays[j].Index(i)
			if ok {
				rv[i].SetField(b.Variable(), v)
			}
		}
	}

	return rv, nil
}

/*
Qualify all identifiers for the parent expression. Checks for
duplicate aliases.
*/
func (this *SubqueryTerm) Formalize(parent *expression.Formalizer) (f *expression.Formalizer, err error) {
	err = this.subquery.Formalize()
	if err != nil {
		return
	}

	alias := this.Alias()
	if alias == "" {
		err = errors.NewNoTermNameError("FROM", "plan.subquery.requires_name_or_alias")
		return
	}

	_, ok := parent.Allowed.Field(alias)
	if ok {
		err = errors.NewDuplicateAliasError("subquery", alias, "plan.subquery.duplicate_alias")
		return nil, err
	}

	allowed := value.NewScopeValue(make(map[string]interface{}), parent.Allowed)
	allowed.SetField(alias, alias)

	f = expression.NewFormalizer()
	f.Keyspace = alias
	f.Allowed = allowed
	return
}

func (this *KeyScan) RunOnce(context *Context, parent value.Value) {
	this.once.Do(func() {
		defer context.Recover()       // Recover from any panic
		defer close(this.itemChannel) // Broadcast that I have stopped
		defer this.notify()           // Notify that I have stopped

		keys, e := this.plan.Keys().Evaluate(parent, context)
		if e != nil {
			context.Error(errors.NewEvaluationError(e, "KEYS"))
			return
		}

		actuals := keys.Actual()
		switch actuals.(type) {
		case []interface{}:
		case nil:
			actuals = []interface{}(nil)
		default:
			actuals = []interface{}{actuals}
		}

		acts := actuals.([]interface{})

		for _, key := range acts {
			cv := value.NewScopeValue(make(map[string]interface{}), parent)
			av := value.NewAnnotatedValue(cv)
			av.SetAttachment("meta", map[string]interface{}{"id": key})
			if !this.sendItem(av) {
				return
			}
		}
	})
}

func (this *Any) Evaluate(item value.Value, context Context) (value.Value, error) {
	missing := false
	null := false

	barr := make([][]interface{}, len(this.bindings))
	for i, b := range this.bindings {
		bv, err := b.Expression().Evaluate(item, context)
		if err != nil {
			return nil, err
		}

		if b.Descend() {
			buffer := make([]interface{}, 0, 256)
			bv = value.NewValue(bv.Descendants(buffer))
		}

		switch bv.Type() {
		case value.ARRAY:
			barr[i] = bv.Actual().([]interface{})
		case value.MISSING:
			missing = true
		default:
			null = true
		}
	}

	if missing {
		return value.MISSING_VALUE, nil
	}

	if null {
		return value.NULL_VALUE, nil
	}

	n := -1
	for _, b := range barr {
		if n < 0 || len(b) < n {
			n = len(b)
		}
	}

	for i := 0; i < n; i++ {
		cv := value.NewScopeValue(make(map[string]interface{}, len(this.bindings)), item)
		for j, b := range this.bindings {
			cv.SetField(b.Variable(), barr[j][i])
		}

		sv, err := this.satisfies.Evaluate(cv, context)
		if err != nil {
			return nil, err
		}

		if sv.Truth() {
			return value.NewValue(true), nil
		}
	}

	return value.NewValue(false), nil
}

/*
This method returns a pointer to a Formalizer struct
with Allowed set to a new map of type string to interface.
*/
func NewFormalizer() *Formalizer {
	rv := &Formalizer{
		Allowed: value.NewScopeValue(make(map[string]interface{}), nil),
	}

	rv.mapper = rv
	return rv
}

func (this *spanScan) RunOnce(context *Context, parent value.Value) {
	this.once.Do(func() {
		defer context.Recover()       // Recover from any panic
		defer close(this.itemChannel) // Broadcast that I have stopped
		defer this.notify()           // Notify that I have stopped

		conn := datastore.NewIndexConnection(context)
		defer notifyConn(conn) // Notify index that I have stopped

		var duration time.Duration
		timer := time.Now()
		defer context.AddPhaseTime("scan", time.Since(timer)-duration)

		go this.scan(context, conn)

		var entry *datastore.IndexEntry
		ok := true
		for ok {
			select {
			case <-this.stopChannel:
				return
			default:
			}

			select {
			case entry, ok = <-conn.EntryChannel():
				t := time.Now()

				if ok {
					cv := value.NewScopeValue(make(map[string]interface{}), parent)
					av := value.NewAnnotatedValue(cv)
					meta := map[string]interface{}{"id": entry.PrimaryKey}
					av.SetAttachment("meta", meta)

					covers := this.plan.Covers()
					if len(covers) > 0 {
						for i, c := range covers {
							if i == 0 {
								av.SetCover(c.Text(), value.NewValue(entry.PrimaryKey))
							} else {
								av.SetCover(c.Text(), entry.EntryKey[i-1])
							}
						}

						av.SetField(this.plan.Term().Alias(), av)
					}

					ok = this.sendItem(av)
				}

				duration += time.Since(t)
			case <-this.stopChannel:
				return
			}
		}
	})
}

func (this *PrimaryScan) scanPrimary(context *Context, parent value.Value) {
	conn := this.newIndexConnection(context)
	defer notifyConn(conn.StopChannel()) // Notify index that I have stopped

	var duration time.Duration
	timer := time.Now()
	defer context.AddPhaseTime("scan", time.Since(timer)-duration)

	go this.scanEntries(context, conn)

	var entry, lastEntry *datastore.IndexEntry

	ok := true
	nitems := 0

	for ok {
		select {
		case <-this.stopChannel:
			return
		default:
		}

		select {
		case entry, ok = <-conn.EntryChannel():
			t := time.Now()

			if ok {
				cv := value.NewScopeValue(make(map[string]interface{}), parent)
				av := value.NewAnnotatedValue(cv)
				av.SetAttachment("meta", map[string]interface{}{"id": entry.PrimaryKey})
				ok = this.sendItem(av)
				lastEntry = entry
				nitems++
			}

			duration += time.Since(t)
		case <-this.stopChannel:
			return
		}

	}

	if conn.Timeout() {
		logging.Errorp("Primary index scan timeout - resorting to chunked scan",
			logging.Pair{"chunkSize", nitems},
			logging.Pair{"startingEntry", lastEntry})
		if lastEntry == nil {
			// no key for chunked scans (primary scan returned 0 items)
			context.Error(errors.NewCbIndexScanTimeoutError(nil))
		}
		// do chunked scans; nitems gives the chunk size, and lastEntry the starting point
		for lastEntry != nil {
			lastEntry = this.scanPrimaryChunk(context, parent, nitems, lastEntry)
		}
	}
}

func (this *DummyScan) RunOnce(context *Context, parent value.Value) {
	this.once.Do(func() {
		defer context.Recover()       // Recover from any panic
		defer close(this.itemChannel) // Broadcast that I have stopped
		defer this.notify()           // Notify that I have stopped

		cv := value.NewScopeValue(nil, parent)
		av := value.NewAnnotatedValue(cv)
		this.sendItem(av)
	})
}

/*
Qualify identifiers for the keyspace. It also makes sure that the
keyspace term contains a name or alias.
*/
func (this *KeyspaceRef) Formalize() (f *expression.Formalizer, err error) {
	keyspace := this.Alias()
	if keyspace == "" {
		err = errors.NewNoTermNameError("Keyspace", "plan.keyspace.reference_requires_name_or_alias")
		return
	}

	allowed := value.NewScopeValue(make(map[string]interface{}), nil)
	allowed.SetField(keyspace, keyspace)

	f = expression.NewFormalizer()
	f.Keyspace = keyspace
	f.Allowed = allowed
	return
}

func (this *InitialProject) processTerms(item value.AnnotatedValue, context *Context) bool {
	n := len(this.plan.Terms())
	sv := value.NewScopeValue(make(map[string]interface{}, n), item)
	pv := value.NewAnnotatedValue(sv)
	pv.SetAnnotations(item)

	p := value.NewValue(make(map[string]interface{}, n+32))
	pv.SetAttachment("projection", p)

	for _, term := range this.plan.Terms() {
		if term.Result().Alias() != "" {
			v, err := term.Result().Expression().Evaluate(item, context)
			if err != nil {
				context.Error(errors.NewEvaluationError(err, "projection"))
				return false
			}

			p.SetField(term.Result().Alias(), v)

			// Explicit aliases override data
			if term.Result().As() != "" {
				pv.SetField(term.Result().As(), v)
			}
		} else {
			// Star
			starval := item.GetValue()
			if term.Result().Expression() != nil {
				var err error
				starval, err = term.Result().Expression().Evaluate(item, context)
				if err != nil {
					context.Error(errors.NewEvaluationError(err, "projection"))
					return false
				}
			}

			// Latest star overwrites previous star
			switch sa := starval.Actual().(type) {
			case map[string]interface{}:
				for k, v := range sa {
					p.SetField(k, v)
				}
			}
		}
	}

	return this.sendItem(pv)
}

func (this *InitialProject) processItem(item value.AnnotatedValue, context *Context) bool {
	terms := this.plan.Terms()
	n := len(terms)

	if n > 1 {
		return this.processTerms(item, context)
	}

	if n == 0 {
		return this.sendItem(item)
	}

	// n == 1

	result := terms[0].Result()
	expr := result.Expression()

	if result.Star() && (expr == expression.SELF || expr == nil) {
		// Unprefixed star
		if item.Type() == value.OBJECT {
			return this.sendItem(item)
		} else {
			return this.sendItem(_EMPTY_ANNOTATED_VALUE)
		}
	} else if this.plan.Projection().Raw() {
		// Raw projection of an expression
		v, err := expr.Evaluate(item, context)
		if err != nil {
			context.Error(errors.NewEvaluationError(err, "projection"))
			return false
		}

		if result.As() == "" {
			return this.sendItem(value.NewAnnotatedValue(v))
		}

		sv := value.NewScopeValue(make(map[string]interface{}, 1), item)
		sv.SetField(result.As(), v)
		av := value.NewAnnotatedValue(sv)
		av.SetAttachment("projection", v)
		return this.sendItem(av)
	} else {
		// Any other projection
		return this.processTerms(item, context)
	}
}

func (this *PrimaryScan) scanPrimaryChunk(context *Context, parent value.Value, chunkSize int, indexEntry *datastore.IndexEntry) *datastore.IndexEntry {
	conn, _ := datastore.NewSizedIndexConnection(int64(chunkSize), context)
	conn.SetPrimary()
	defer notifyConn(conn.StopChannel()) // Notify index that I have stopped

	var duration time.Duration
	timer := time.Now()
	defer context.AddPhaseTime("scan", time.Since(timer)-duration)

	go this.scanChunk(context, conn, chunkSize, indexEntry)

	var entry, lastEntry *datastore.IndexEntry

	ok := true
	nitems := 0

	for ok {
		select {
		case <-this.stopChannel:
			return nil
		default:
		}

		select {
		case entry, ok = <-conn.EntryChannel():
			t := time.Now()

			if ok {
				cv := value.NewScopeValue(make(map[string]interface{}), parent)
				av := value.NewAnnotatedValue(cv)
				av.SetAttachment("meta", map[string]interface{}{"id": entry.PrimaryKey})
				ok = this.sendItem(av)
				lastEntry = entry
				nitems++
			}

			duration += time.Since(t)
		case <-this.stopChannel:
			return nil
		}

	}
	logging.Debugp("Primary index chunked scan", logging.Pair{"chunkSize", nitems}, logging.Pair{"lastKey", lastEntry})
	return lastEntry
}

func (this *Let) processItem(item value.AnnotatedValue, context *Context) bool {
	n := len(this.plan.Bindings())
	cv := value.NewScopeValue(make(map[string]interface{}, n), item)
	lv := value.NewAnnotatedValue(cv)
	lv.SetAnnotations(item)

	for _, b := range this.plan.Bindings() {
		v, e := b.Expression().Evaluate(item, context)
		if e != nil {
			context.Error(errors.NewEvaluationError(e, "LET"))
			return false
		}

		lv.SetField(b.Variable(), v)
	}

	return this.sendItem(lv)
}

/*
This method returns a pointer to a Formalizer struct
with allowed set to a new map of type string to interface.
*/
func NewFormalizer(keyspace string, parent *Formalizer) *Formalizer {
	var pv value.Value
	if parent != nil {
		pv = parent.allowed
	}

	rv := &Formalizer{
		keyspace:    keyspace,
		allowed:     value.NewScopeValue(make(map[string]interface{}), pv),
		identifiers: make(map[string]bool),
	}

	if keyspace != "" {
		rv.allowed.SetField(keyspace, keyspace)
	}

	rv.mapper = rv
	return rv
}