From f1b7a86cf6c893b5fce5dddbb70cd0bc6007a58a Mon Sep 17 00:00:00 2001
From: Nanaloveyuki <miaomiao_159@outlook.com>
Date: Sat, 13 Jun 2026 23:05:08 +0800
Subject: [PATCH] :memo: document runtime sink reopen methods

---
 docs/api/index.md                             |  5 ++
 docs/api/runtime-sink-file-available.md       | 76 +++++++++++++++++++
 docs/api/runtime-sink-file-reopen-append.md   | 74 ++++++++++++++++++
 docs/api/runtime-sink-file-reopen-truncate.md | 74 ++++++++++++++++++
 ...me-sink-file-reopen-with-current-policy.md | 74 ++++++++++++++++++
 docs/api/runtime-sink-file-reopen.md          | 75 ++++++++++++++++++
 6 files changed, 378 insertions(+)
 create mode 100644 docs/api/runtime-sink-file-available.md
 create mode 100644 docs/api/runtime-sink-file-reopen-append.md
 create mode 100644 docs/api/runtime-sink-file-reopen-truncate.md
 create mode 100644 docs/api/runtime-sink-file-reopen-with-current-policy.md
 create mode 100644 docs/api/runtime-sink-file-reopen.md

diff --git a/docs/api/index.md b/docs/api/index.md
index 0537ddc..954dd68 100644
--- a/docs/api/index.md
+++ b/docs/api/index.md
@@ -362,6 +362,11 @@ BitLogger API navigation.
 - [runtime-sink-pending-count.md](./runtime-sink-pending-count.md)
 - [runtime-sink-dropped-count.md](./runtime-sink-dropped-count.md)
 - [runtime-sink-file-path.md](./runtime-sink-file-path.md)
+- [runtime-sink-file-available.md](./runtime-sink-file-available.md)
+- [runtime-sink-file-reopen.md](./runtime-sink-file-reopen.md)
+- [runtime-sink-file-reopen-with-current-policy.md](./runtime-sink-file-reopen-with-current-policy.md)
+- [runtime-sink-file-reopen-append.md](./runtime-sink-file-reopen-append.md)
+- [runtime-sink-file-reopen-truncate.md](./runtime-sink-file-reopen-truncate.md)
 - [runtime-sink-file-append-mode.md](./runtime-sink-file-append-mode.md)
 - [runtime-sink-file-set-append-mode.md](./runtime-sink-file-set-append-mode.md)
 - [runtime-sink-file-auto-flush.md](./runtime-sink-file-auto-flush.md)
diff --git a/docs/api/runtime-sink-file-available.md b/docs/api/runtime-sink-file-available.md
new file mode 100644
index 0000000..11e3306
--- /dev/null
+++ b/docs/api/runtime-sink-file-available.md
@@ -0,0 +1,76 @@
+---
+name: runtime-sink-file-available
+group: api
+category: runtime
+update-time: 20260613
+description: Read whether a RuntimeSink currently has an available file sink behind its runtime sink shape.
+key-word:
+    - runtime
+    - sink
+    - file
+    - public
+---
+
+## Runtime-sink-file-available
+
+Read whether a `RuntimeSink` currently has an available file sink. This helper is useful for direct runtime diagnostics and recovery checks when code owns a runtime sink value instead of a `ConfiguredLogger`.
+
+### Interface
+
+```moonbit
+pub fn RuntimeSink::file_available(self : RuntimeSink) -> Bool {
+```
+
+#### input
+
+- `self : RuntimeSink` - Runtime sink whose file sink availability should be inspected.
+
+#### output
+
+- `Bool` - Whether an underlying file sink is available.
+
+### Explanation
+
+Detailed rules explaining key parameters and behaviors
+
+- Plain `File` runtime variants report actual file availability.
+- `QueuedFile` runtime variants expose the availability of their wrapped inner file sink.
+- Non-file runtime variants return `false`.
+- This helper does not mutate runtime sink state.
+
+### How to Use
+
+Here are some specific examples provided.
+
+#### When Need Direct Runtime File Health Checks
+
+When operators or code should check file sink readiness on a runtime sink value:
+```moonbit
+if !sink.file_available() {
+  println("file sink unavailable")
+}
+```
+
+In this example, the runtime sink exposes file health directly.
+
+#### When Gate Direct Recovery Logic
+
+When reopen or fallback behavior depends on file availability:
+```moonbit
+let ok = sink.file_available()
+```
+
+In this example, callers can decide whether a recovery action is needed.
+
+### Error Case
+
+e.g.:
+- If the runtime sink is not file-backed, the method returns `false`.
+
+- If callers need detailed failure counters rather than a simple availability flag, `file_state()` or `file_runtime_state()` is the better API.
+
+### Notes
+
+1. Use this helper for lightweight file sink health checks on direct `RuntimeSink` values.
+
+2. Pair it with reopen and failure-counter APIs when diagnosing file sink problems.
diff --git a/docs/api/runtime-sink-file-reopen-append.md b/docs/api/runtime-sink-file-reopen-append.md
new file mode 100644
index 0000000..22c567b
--- /dev/null
+++ b/docs/api/runtime-sink-file-reopen-append.md
@@ -0,0 +1,74 @@
+---
+name: runtime-sink-file-reopen-append
+group: api
+category: runtime
+update-time: 20260613
+description: Reopen the file sink behind a RuntimeSink in append mode.
+key-word:
+    - runtime
+    - sink
+    - file
+    - public
+---
+
+## Runtime-sink-file-reopen-append
+
+Reopen the file sink behind a `RuntimeSink` in append mode. This helper is the explicit append-oriented direct recovery shortcut.
+
+### Interface
+
+```moonbit
+pub fn RuntimeSink::file_reopen_append(self : RuntimeSink) -> Bool {
+```
+
+#### input
+
+- `self : RuntimeSink` - Runtime sink whose file sink should be reopened in append mode.
+
+#### output
+
+- `Bool` - Whether reopen succeeded.
+
+### Explanation
+
+Detailed rules explaining key parameters and behaviors
+
+- Plain `File` runtime variants reopen in append mode.
+- `QueuedFile` runtime variants forward reopen behavior to the wrapped inner file sink.
+- This helper is a specialized shortcut for a common reopen mode.
+- Non-file runtime variants return `false`.
+
+### How to Use
+
+Here are some specific examples provided.
+
+#### When Need Append-preserving Direct Recovery
+
+When file logging should continue appending after a reopen:
+```moonbit
+ignore(sink.file_reopen_append())
+```
+
+In this example, reopen behavior is fixed to append mode.
+
+#### When Want An Explicit Append Shortcut
+
+When code should avoid manually setting append overrides:
+```moonbit
+let ok = sink.file_reopen_append()
+```
+
+In this example, the call site states append intent directly.
+
+### Error Case
+
+e.g.:
+- If the runtime sink is not file-backed, the method returns `false`.
+
+- If callers need truncate behavior instead, `file_reopen_truncate()` is the correct API.
+
+### Notes
+
+1. Use this helper for explicit append-mode reopen flows on direct `RuntimeSink` values.
+
+2. It is especially useful after transient file availability issues.
diff --git a/docs/api/runtime-sink-file-reopen-truncate.md b/docs/api/runtime-sink-file-reopen-truncate.md
new file mode 100644
index 0000000..9895a3d
--- /dev/null
+++ b/docs/api/runtime-sink-file-reopen-truncate.md
@@ -0,0 +1,74 @@
+---
+name: runtime-sink-file-reopen-truncate
+group: api
+category: runtime
+update-time: 20260613
+description: Reopen the file sink behind a RuntimeSink in truncate mode.
+key-word:
+    - runtime
+    - sink
+    - file
+    - public
+---
+
+## Runtime-sink-file-reopen-truncate
+
+Reopen the file sink behind a `RuntimeSink` in truncate mode. This helper is the explicit truncate-oriented direct recovery or reset shortcut.
+
+### Interface
+
+```moonbit
+pub fn RuntimeSink::file_reopen_truncate(self : RuntimeSink) -> Bool {
+```
+
+#### input
+
+- `self : RuntimeSink` - Runtime sink whose file sink should be reopened in truncate mode.
+
+#### output
+
+- `Bool` - Whether reopen succeeded.
+
+### Explanation
+
+Detailed rules explaining key parameters and behaviors
+
+- Plain `File` runtime variants reopen in truncate mode.
+- `QueuedFile` runtime variants forward reopen behavior to the wrapped inner file sink.
+- This helper is a specialized shortcut for a common reset-style reopen mode.
+- Non-file runtime variants return `false`.
+
+### How to Use
+
+Here are some specific examples provided.
+
+#### When Need A Fresh Output File
+
+When a runtime file should be reopened from an empty state:
+```moonbit
+ignore(sink.file_reopen_truncate())
+```
+
+In this example, reopen behavior truncates the file before future writes continue.
+
+#### When Want An Explicit Truncate Shortcut
+
+When code should make destructive reopen intent obvious:
+```moonbit
+let ok = sink.file_reopen_truncate()
+```
+
+In this example, the call site expresses reset-style reopen behavior directly.
+
+### Error Case
+
+e.g.:
+- If the runtime sink is not file-backed, the method returns `false`.
+
+- If callers want to preserve existing file content, `file_reopen_append()` is the correct API.
+
+### Notes
+
+1. Use this helper when starting from a fresh file is intentional.
+
+2. Truncate-mode reopen is a stronger action than generic reopen recovery.
diff --git a/docs/api/runtime-sink-file-reopen-with-current-policy.md b/docs/api/runtime-sink-file-reopen-with-current-policy.md
new file mode 100644
index 0000000..d2ca245
--- /dev/null
+++ b/docs/api/runtime-sink-file-reopen-with-current-policy.md
@@ -0,0 +1,74 @@
+---
+name: runtime-sink-file-reopen-with-current-policy
+group: api
+category: runtime
+update-time: 20260613
+description: Reopen the file sink behind a RuntimeSink using its currently stored runtime policy.
+key-word:
+    - runtime
+    - sink
+    - file
+    - public
+---
+
+## Runtime-sink-file-reopen-with-current-policy
+
+Reopen the file sink behind a `RuntimeSink` using the currently stored runtime policy. This helper is useful when callers want direct recovery behavior without supplying a one-off append override.
+
+### Interface
+
+```moonbit
+pub fn RuntimeSink::file_reopen_with_current_policy(self : RuntimeSink) -> Bool {
+```
+
+#### input
+
+- `self : RuntimeSink` - Runtime sink whose file sink should be reopened with current policy.
+
+#### output
+
+- `Bool` - Whether reopen succeeded.
+
+### Explanation
+
+Detailed rules explaining key parameters and behaviors
+
+- Plain `File` runtime variants reuse their current stored reopen policy.
+- `QueuedFile` runtime variants forward reopen behavior to the wrapped inner file sink.
+- This helper differs from `file_reopen(...)` because it does not accept a per-call append override.
+- Non-file runtime variants return `false`.
+
+### How to Use
+
+Here are some specific examples provided.
+
+#### When Need Policy-preserving Direct Recovery
+
+When a file sink should be reopened without changing runtime append behavior:
+```moonbit
+ignore(sink.file_reopen_with_current_policy())
+```
+
+In this example, recovery reuses the runtime policy already stored on the sink.
+
+#### When Separate Recovery From Policy Mutation
+
+When append mode should be controlled elsewhere:
+```moonbit
+let ok = sink.file_reopen_with_current_policy()
+```
+
+In this example, reopen is explicit while policy mutation stays separate.
+
+### Error Case
+
+e.g.:
+- If the runtime sink is not file-backed, the method returns `false`.
+
+- If callers want to change append behavior during reopen, `file_reopen(...)` or `file_reopen_append()` / `file_reopen_truncate()` are better APIs.
+
+### Notes
+
+1. Use this helper when direct recovery should respect the currently stored runtime policy.
+
+2. It is clearer than passing no override through a more general reopen API.
diff --git a/docs/api/runtime-sink-file-reopen.md b/docs/api/runtime-sink-file-reopen.md
new file mode 100644
index 0000000..94f76f1
--- /dev/null
+++ b/docs/api/runtime-sink-file-reopen.md
@@ -0,0 +1,75 @@
+---
+name: runtime-sink-file-reopen
+group: api
+category: runtime
+update-time: 20260613
+description: Reopen the file sink behind a RuntimeSink with an optional append-mode override.
+key-word:
+    - runtime
+    - sink
+    - file
+    - public
+---
+
+## Runtime-sink-file-reopen
+
+Reopen the file sink behind a `RuntimeSink`. This helper is useful for direct recovery flows after file unavailability or policy changes.
+
+### Interface
+
+```moonbit
+pub fn RuntimeSink::file_reopen(self : RuntimeSink, append~ : Bool? = None) -> Bool {
+```
+
+#### input
+
+- `self : RuntimeSink` - Runtime sink whose file sink should be reopened.
+- `append : Bool?` - Optional append-mode override used for reopen behavior.
+
+#### output
+
+- `Bool` - Whether reopen succeeded.
+
+### Explanation
+
+Detailed rules explaining key parameters and behaviors
+
+- Plain `File` runtime variants reopen directly.
+- `QueuedFile` runtime variants forward reopen behavior to the wrapped inner file sink.
+- `append=None` preserves current reopen policy, while `Some(true/false)` overrides append mode.
+- Non-file runtime variants return `false`.
+
+### How to Use
+
+Here are some specific examples provided.
+
+#### When Need Recovery After File Failure
+
+When code should attempt to restore file logging through a `RuntimeSink` value:
+```moonbit
+ignore(sink.file_reopen())
+```
+
+In this example, the runtime sink tries to reopen its file sink using current policy.
+
+#### When Need Explicit Append-mode Reopen
+
+When recovery should choose append or truncate behavior explicitly:
+```moonbit
+let ok = sink.file_reopen(append=Some(true))
+```
+
+In this example, reopen behavior is directed by the call site.
+
+### Error Case
+
+e.g.:
+- If the runtime sink is not file-backed, the method returns `false`.
+
+- If callers only need the current configured policy, `file_reopen_with_current_policy()` may be the clearer API.
+
+### Notes
+
+1. Use this helper for explicit direct recovery flows on `RuntimeSink` values.
+
+2. Pair it with `file_available()` and failure counters when diagnosing reopen behavior.