func (this *InitialProject) processTerms(item value.AnnotatedValue, context *Context) bool {
n := len(this.plan.Terms())
var f map[string]interface{}
if item.Type() == value.OBJECT {
f = item.Copy().Fields()
}
if f == nil {
f = make(map[string]interface{}, n)
}
pv := value.NewAnnotatedValue(f)
pv.SetAttachments(item.Attachments())
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.NewError(err, "Error evaluating 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.NewError(err, "Error evaluating 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 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.NewError(err, "Error evaluating 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)
}
}
