49 lines
2.0 KiB
Go
49 lines
2.0 KiB
Go
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package experimental
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import (
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"context"
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"github.com/tetratelabs/wazero/internal/expctxkeys"
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)
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// Snapshot holds the execution state at the time of a Snapshotter.Snapshot call.
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type Snapshot interface {
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// Restore sets the Wasm execution state to the capture. Because a host function
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// calling this is resetting the pointer to the executation stack, the host function
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// will not be able to return values in the normal way. ret is a slice of values the
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// host function intends to return from the restored function.
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Restore(ret []uint64)
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}
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// Snapshotter allows host functions to snapshot the WebAssembly execution environment.
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type Snapshotter interface {
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// Snapshot captures the current execution state.
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Snapshot() Snapshot
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}
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// EnableSnapshotterKey is a context key to indicate that snapshotting should be enabled.
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// The context.Context passed to a exported function invocation should have this key set
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// to a non-nil value, and host functions will be able to retrieve it using SnapshotterKey.
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//
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// Deprecated: use WithSnapshotter to enable snapshots.
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type EnableSnapshotterKey = expctxkeys.EnableSnapshotterKey
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// WithSnapshotter enables snapshots.
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// Passing the returned context to a exported function invocation enables snapshots,
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// and allows host functions to retrieve the Snapshotter using GetSnapshotter.
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func WithSnapshotter(ctx context.Context) context.Context {
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return context.WithValue(ctx, expctxkeys.EnableSnapshotterKey{}, struct{}{})
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}
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// SnapshotterKey is a context key to access a Snapshotter from a host function.
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// It is only present if EnableSnapshotter was set in the function invocation context.
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//
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// Deprecated: use GetSnapshotter to get the snapshotter.
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type SnapshotterKey = expctxkeys.SnapshotterKey
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// GetSnapshotter gets the Snapshotter from a host function.
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// It is only present if WithSnapshotter was called with the function invocation context.
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func GetSnapshotter(ctx context.Context) Snapshotter {
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return ctx.Value(expctxkeys.SnapshotterKey{}).(Snapshotter)
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}
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