read cache

MercuryWorkshop · May 17, 2024 · 807b72e · 807b72e
1 parent 1942f8f
commit 807b72e
Showing 1 changed file with 29 additions and 9 deletions.
diff --git a/lib/9p-filer.js b/lib/9p-filer.js
@@ -14,6 +14,8 @@ const VIRTIO_9P_F_MOUNT_TAG = 0;
 // Assumed max tag length in bytes.
 const VIRTIO_9P_MAX_TAGLEN = 254;
 
+const FSCACHE = new Map()
+
 // TODO
 // flush
 
@@ -954,19 +956,37 @@ Virtio9p.prototype.ReceiveRequest = async function(bufchain) {
                 _read(data);
                 return;
             }
+            if (!FSCACHE.has(path))
+                fs.readFile(path, function(err, data) {
+                    if (self.shouldAbortRequest(tag)) return;
 
-            fs.readFile(path, function(err, data) {
-                if (self.shouldAbortRequest(tag)) return;
+                    if (err) {
+                        self.SendError(tag, err);
+                        self.SendReply(bufchain)
+                        return;
+                    }
 
-                if (err) {
-                    self.SendError(tag, err);
-                    self.SendReply(bufchain)
-                    return;
-                }
+                    self.pendingTags[tag].data = data;
+                    FSCACHE.set(path, {data: data, remaining: data.byteLength})
+                    _read(data);
+                });
+            else {
+                const file = FSCACHE.get(path);
+                file.remaining -= count;
 
                 self.pendingTags[tag].data = data;
-                _read(data);
-            });
+                _read(file.data)
+                setTimeout(() => {
+                    if (FSCACHE.has(path)) {
+                        // console.log("Deleted FSCACHE entry for: " + path + "\nReason: over 1 minute");
+                        FSCACHE.delete(path);
+                    }
+                }, 60 * 1000)
+                if (file.remaining <= 0) {
+                    // console.log("Deleted FSCACHE entry for: " + path + "\nReason: Used up");
+                    FSCACHE.delete(path);
+                }
+            }
 
             break;
         case 118: // write