✨ Add queued file runtime state snapshots

bitlogger/BitLogger_test.mbt

@@ -207,6 +207,7 @@ test "configured logger exposes file sink observability helpers" {
     ),
   )
   let state = logger.file_state()
+  let runtime_state = logger.file_runtime_state()
   inspect(logger.file_available() == native_files_supported(), content="true")
   inspect(logger.file_path(), content="config-file.log")
   inspect(state.path, content="config-file.log")
@@ -215,6 +216,15 @@ test "configured logger exposes file sink observability helpers" {
   inspect(state.auto_flush == logger.file_auto_flush(), content="true")
   inspect(logger.file_append_mode(), content="true")
   inspect(logger.file_auto_flush(), content="false")
+  match runtime_state {
+    Some(snapshot) => {
+      inspect(snapshot.queued, content="false")
+      inspect(snapshot.pending_count, content="0")
+      inspect(snapshot.dropped_count, content="0")
+      inspect(snapshot.file.path, content="config-file.log")
+    }
+    None => inspect(false, content="true")
+  }
   inspect(logger.file_rotation_enabled(), content="true")
   match logger.file_rotation_config() {
     Some(rotation) => {
@@ -238,9 +248,20 @@ test "configured logger reports disabled rotation when file sink has none" {
   )
   inspect(logger.file_rotation_enabled(), content="false")
   inspect(logger.file_rotation_config() is None, content="true")
+  match logger.file_runtime_state() {
+    Some(snapshot) => inspect(snapshot.queued, content="false")
+    None => inspect(false, content="true")
+  }
   ignore(logger.close())
 }
 
+test "configured non-file logger has no file runtime state" {
+  let logger = build_logger(
+    LoggerConfig::new(sink=SinkConfig::new(kind=SinkKind::Console)),
+  )
+  inspect(logger.file_runtime_state() is None, content="true")
+}
+
 test "configured logger file setters update file sink policy state" {
   let logger = build_logger(
     LoggerConfig::new(
@@ -343,15 +364,31 @@ test "configured queued file logger flushes queue through file helper" {
   )
   logger.info("one")
   logger.info("two")
+  match logger.file_runtime_state() {
+    Some(snapshot) => {
+      inspect(snapshot.queued, content="true")
+      inspect(snapshot.pending_count, content="2")
+      inspect(snapshot.dropped_count, content="0")
+    }
+    None => inspect(false, content="true")
+  }
   if logger.file_available() {
     inspect(logger.pending_count(), content="2")
     inspect(logger.file_flush(), content="true")
     inspect(logger.pending_count(), content="0")
+    match logger.file_runtime_state() {
+      Some(snapshot) => inspect(snapshot.pending_count, content="0")
+      None => inspect(false, content="true")
+    }
     inspect(logger.file_close(), content="true")
   } else {
     inspect(logger.pending_count(), content="2")
     inspect(logger.file_flush(), content="false")
     inspect(logger.pending_count(), content="0")
+    match logger.file_runtime_state() {
+      Some(snapshot) => inspect(snapshot.pending_count, content="0")
+      None => inspect(false, content="true")
+    }
     inspect(logger.file_close(), content="false")
   }
 }

bitlogger/README.mbt.md

@@ -229,4 +229,5 @@ test {
 - `set_auto_flush(...)`, `set_rotation(...)`, and `clear_rotation()` allow runtime tuning of core file sink policies / `set_auto_flush(...)`、`set_rotation(...)`、`clear_rotation()` 可在运行期调整 file sink 的基础策略
 - `open_failures()`、`write_failures()`、`flush_failures()`、`rotation_failures()` expose basic sink health counters / `open_failures()`、`write_failures()`、`flush_failures()`、`rotation_failures()` 可用于观察基础 sink 健康状态
 - `ConfiguredLogger` also forwards file reopen, flush, close, append-mode, path, auto-flush, rotation-config, state snapshot, append setter, policy setter, and failure-counter helpers for config-built file sinks / `ConfiguredLogger` 也会为配置生成的 file sink 转发 reopen、flush、close、append-mode、path、auto-flush、rotation 配置、state 快照、append setter、策略 setter 与失败计数访问器
+- `ConfiguredLogger::file_runtime_state()` also reports whether a file sink is queue-wrapped and exposes the outer queue pending/drop counters together with the inner file snapshot / `ConfiguredLogger::file_runtime_state()` 还可报告 file sink 是否被 queue 包装，并将外层 queue 的 pending/drop 计数与内层 file 快照一起返回
 - current scope is observability-first, not a full self-healing sink runtime / 当前定位仍以可观测性优先，不是完整自愈型 sink runtime

bitlogger/config.mbt

@@ -137,6 +137,13 @@ pub(all) enum RuntimeSink {
   QueuedFile(QueuedSink[FileSink])
 }
 
+pub struct RuntimeFileState {
+  file : FileSinkState
+  queued : Bool
+  pending_count : Int
+  dropped_count : Int
+}
+
 pub impl Sink for RuntimeSink with write(self, rec) {
   match self {
     Console(sink) => sink.write(rec)
@@ -423,6 +430,24 @@ pub fn RuntimeSink::file_state(self : RuntimeSink) -> FileSinkState {
   }
 }
 
+pub fn RuntimeSink::file_runtime_state(self : RuntimeSink) -> RuntimeFileState? {
+  match self {
+    File(sink) => Some({
+      file: sink.state(),
+      queued: false,
+      pending_count: 0,
+      dropped_count: 0,
+    })
+    QueuedFile(sink) => Some({
+      file: sink.sink.state(),
+      queued: true,
+      pending_count: sink.pending_count(),
+      dropped_count: sink.dropped_count(),
+    })
+    _ => None
+  }
+}
+
 pub type ConfiguredLogger = Logger[RuntimeSink]
 
 pub fn ConfiguredLogger::flush(self : ConfiguredLogger) -> Int {
@@ -532,6 +557,10 @@ pub fn ConfiguredLogger::file_state(self : ConfiguredLogger) -> FileSinkState {
   self.sink.file_state()
 }
 
+pub fn ConfiguredLogger::file_runtime_state(self : ConfiguredLogger) -> RuntimeFileState? {
+  self.sink.file_runtime_state()
+}
+
 fn expect_object(
   value : @json_parser.JsonValue,
   context : String,