[Init] Initial commit - NetMesh terminal manager

electron/preload/terminalDataBacklog.cjs

@@ -0,0 +1,139 @@
+"use strict";
+
+const { mergeTerminalDataMeta } = require("./terminalDataMeta.cjs");
+
+function hasPluginPipelineIngress(meta) {
+  return Number.isFinite(meta?.pluginPipelineIngressBytes)
+    && Number(meta.pluginPipelineIngressBytes) > 0;
+}
+
+function hasPluginPipelineIngressMarker(meta) {
+  return Number.isFinite(meta?.pluginPipelineIngressBytes)
+    && Number(meta.pluginPipelineIngressBytes) >= 0;
+}
+
+function createTerminalDataBacklog(options = {}) {
+  const maxBytesPerSession = options.maxBytesPerSession ?? 64 * 1024;
+  const pendingBySession = new Map();
+
+  function trimToLimit(value) {
+    if (value.length <= maxBytesPerSession) return value;
+    return value.slice(value.length - maxBytesPerSession);
+  }
+
+  function append(sessionId, data, meta) {
+    if (!sessionId || (!data && !hasPluginPipelineIngressMarker(meta))) return;
+    const previous = pendingBySession.get(sessionId) || { data: "", meta: undefined };
+    const nextData = trimToLimit(previous.data + data);
+    const preserveTerminalPerf = previous.data.length === 0 && nextData === data;
+    let previousMeta = previous.meta;
+    let nextChunkMeta = meta;
+    const previousHasIngress = Number.isFinite(previousMeta?.pluginPipelineIngressBytes);
+    const nextChunkHasIngress = Number.isFinite(nextChunkMeta?.pluginPipelineIngressBytes);
+    // Once one merged chunk carries explicit original-ingress accounting, the
+    // metadata must cover every raw flow unit in the same replay entry. Flow
+    // control is intentionally charged in JavaScript string length, not UTF-8
+    // bytes, throughout the terminal renderer/worker path. Otherwise a
+    // processed chunk followed or preceded by ordinary output would cause the
+    // renderer to acknowledge only the annotated subset.
+    if (previousHasIngress && !nextChunkHasIngress && data) {
+      nextChunkMeta = {
+        ...(nextChunkMeta || {}),
+        pluginPipelineIngressBytes: data.length,
+      };
+    } else if (!previousHasIngress && nextChunkHasIngress && previous.data) {
+      previousMeta = {
+        ...(previousMeta || {}),
+        pluginPipelineIngressBytes: previous.data.length,
+      };
+    }
+    const nextMeta = mergeTerminalDataMeta(previousMeta, nextChunkMeta, { preserveTerminalPerf });
+    pendingBySession.set(sessionId, {
+      data: nextData,
+      meta: nextMeta,
+    });
+  }
+
+  function takeEntry(sessionId) {
+    const entry = pendingBySession.get(sessionId) || { data: "", meta: undefined };
+    pendingBySession.delete(sessionId);
+    return entry;
+  }
+
+  function take(sessionId) {
+    return takeEntry(sessionId).data;
+  }
+
+  function clear(sessionId) {
+    pendingBySession.delete(sessionId);
+  }
+
+  function size(sessionId) {
+    return pendingBySession.get(sessionId)?.data.length ?? 0;
+  }
+
+  return {
+    append,
+    take,
+    takeEntry,
+    clear,
+    size,
+  };
+}
+
+function hasSessionListeners(listenersBySession, sessionId) {
+  return (listenersBySession.get(sessionId)?.size ?? 0) > 0;
+}
+
+function createTerminalDataDispatcher({
+  dataListeners,
+  displayDataListeners,
+  terminalDataBacklog,
+  onCallbackError = console.error,
+  shouldDropSession = () => false,
+}) {
+  return function deliverToListeners(sessionId, data, meta) {
+    if (!data && !hasPluginPipelineIngressMarker(meta)) return;
+    if (shouldDropSession(sessionId)) return;
+
+    if (!hasSessionListeners(displayDataListeners, sessionId)) {
+      terminalDataBacklog?.append?.(sessionId, data, meta);
+    }
+
+    const set = dataListeners.get(sessionId);
+    if (!set || set.size === 0) return;
+
+    set.forEach((cb) => {
+      try {
+        cb(data, meta);
+      } catch (err) {
+        onCallbackError("Data callback failed", err);
+      }
+    });
+  };
+}
+
+function clearTerminalDataSession({
+  dataListeners,
+  displayDataListeners,
+  terminalDataBacklog,
+}, sessionId) {
+  dataListeners?.delete?.(sessionId);
+  displayDataListeners?.delete?.(sessionId);
+  terminalDataBacklog?.clear?.(sessionId);
+}
+
+function clearTerminalDataBacklog({
+  terminalDataBacklog,
+}, sessionId) {
+  terminalDataBacklog?.clear?.(sessionId);
+}
+
+module.exports = {
+  clearTerminalDataBacklog,
+  createTerminalDataBacklog,
+  createTerminalDataDispatcher,
+  clearTerminalDataSession,
+  hasPluginPipelineIngress,
+  hasPluginPipelineIngressMarker,
+};