52 lines
1.3 KiB
Go
52 lines
1.3 KiB
Go
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package diff
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import (
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"sync"
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)
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// LazyResourceMap is a way to lazy-load resource builders.
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//
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// By lazy loading resource builders, a considerable amount of compute
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// effort for building the builders can be avoided. This is especially
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// helpful in Terraform providers that support many resource types.
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type LazyResourceMap struct {
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Resources map[string]ResourceBuilderFactory
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l sync.Mutex
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memoized map[string]*ResourceBuilder
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}
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// ResourceBuilderFactory is a factory function for creating a resource
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// builder that is used for lazy loading resource builders in the Builder
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// struct.
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type ResourceBuilderFactory func() *ResourceBuilder
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// Get gets the ResourceBuilder for the given resource type, and returns
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// nil if the resource builder cannot be found.
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//
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// This will memoize the result, returning the same result for the same
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// type if called again.
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func (m *LazyResourceMap) Get(r string) *ResourceBuilder {
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m.l.Lock()
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defer m.l.Unlock()
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// If we have it saved, return that
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if rb, ok := m.memoized[r]; ok {
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return rb
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}
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// Get the factory function
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f, ok := m.Resources[r]
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if !ok {
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return nil
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}
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// Save it so that we don't rebuild
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if m.memoized == nil {
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m.memoized = make(map[string]*ResourceBuilder)
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}
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m.memoized[r] = f()
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return m.memoized[r]
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}
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