57 lines
1.4 KiB
Go
57 lines
1.4 KiB
Go
package engine
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import (
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"context"
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"io"
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"git.defalsify.org/festive/persist"
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"git.defalsify.org/festive/resource"
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)
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// RunPersisted performs a single vm execution from client input using a persisted state.
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//
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// State is first loaded from storage. The vm is initialized with the state and executed. The new state is then saved to storage.
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//
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// The resulting output of the execution will be written to the provided writer.
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//
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// The state is identified by the SessionId member of the Config. Before first execution, the caller must ensure that an
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// initialized state actually is available for the identifier, otherwise the method will fail.
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//
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// It will also fail if execution by the underlying Engine fails.
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func RunPersisted(cfg Config, rs resource.Resource, pr persist.Persister, input []byte, w io.Writer, ctx context.Context) error {
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err := pr.Load(cfg.SessionId)
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if err != nil {
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return err
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}
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st := pr.GetState()
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location, idx := st.Where()
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if location != "" {
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cfg.Root = location
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}
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en := NewEngine(cfg, pr.GetState(), rs, pr.GetMemory(), ctx)
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c, err := en.WriteResult(w, ctx)
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if err != nil {
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return err
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}
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err = pr.Save(cfg.SessionId)
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if err != nil {
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return err
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}
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if c > 0 {
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return err
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}
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_ = idx
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_, err = en.Exec(input, ctx)
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if err != nil {
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return err
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}
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_, err = en.WriteResult(w, ctx)
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if err != nil {
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return err
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}
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return pr.Save(cfg.SessionId)
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}
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