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Nanaloveyuki
77 lines
2.0 KiB
Markdown
77 lines
2.0 KiB
Markdown
---
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name: file-sink-available
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group: api
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category: sink
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update-time: 20260613
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description: Read whether a FileSink currently has an available underlying file handle.
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key-word:
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- file
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- sink
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- available
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- public
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---
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## File-sink-available
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Read whether a `FileSink` currently has an available underlying file handle. This helper is useful for runtime diagnostics and for deciding whether reopen or fallback behavior is needed.
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### Interface
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```moonbit
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pub fn FileSink::is_available(self : FileSink) -> Bool {
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```
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#### input
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- `self : FileSink` - File sink whose current availability should be inspected.
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#### output
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- `Bool` - Whether the sink currently holds an active file handle.
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### Explanation
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Detailed rules explaining key parameters and behaviors
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- This method reports whether `self.handle` is currently `Some(_)`.
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- A sink can become unavailable after open failure or after an explicit `close()`.
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- This helper does not mutate sink state.
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- It is the direct `FileSink` counterpart to configured-logger file availability checks.
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### How to Use
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Here are some specific examples provided.
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#### When Need Direct Sink Health Checks
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When code works with a concrete file sink and should verify handle readiness:
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```moonbit
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if !sink.is_available() {
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println("file sink unavailable")
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}
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```
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In this example, the caller can detect whether the sink currently has an active file handle.
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#### When Gate Recovery Or Reopen Logic
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When a reopen step should only run after loss of availability:
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```moonbit
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let ok = sink.is_available()
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```
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In this example, the boolean result can drive later recovery behavior.
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### Error Case
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e.g.:
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- If the sink failed to open initially, this method returns `false`.
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- If callers need failure counters or a richer state snapshot rather than a yes-or-no result, `state()` is the better API.
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### Notes
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1. Use this helper for lightweight file sink health checks.
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2. Pair it with `reopen(...)`, `state()`, or failure-counter APIs when diagnosing file sink problems.
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