aligned-block-file - npm Package Compare versions

Comparing version 1.2.1 to 1.2.2

file.js

@@ -5,2 +5,3 @@ var fs = require('fs')
 var path = require('path')
+const ReadWriteLock = require('rwlock');
 
@@ -17,46 +18,12 @@ module.exports = function (file, block_size, flags) {
   //
-  // It's possible (likely?) that Node.js handles this deeper in the stack,
-  // especially since it seems to use `pread()` and `pwrite()`. Removing this
-  // queue system doesn't break any tests, but I'm not confident enough to
-  // remove it until we confirm that Node.js handles concurrent positional
-  // reads and writes without either of the concurrency problems above.
+  // It's likely that Node.js is handling this deeper in the stack with libuv
+  // operations like `pread()` and `pwrite()`, but they haven't explicitly
+  // committed to this behavior:
   //
-  // This async queue system is made of four parts:
+  // https://github.com/nodejs/node/issues/18634#issuecomment-363981993
   //
-  // - `busy`: A boolean semaphore for positional reads and writes to `fd`.
-  // - `queue`: An array of functions that want to access `fd`.
-  // - `todo(fn)`: Used to run or queue `fn`, which must call `release()`.
-  // - `release()`: Called by functions passed to `todo()` after using `fd`.
-
-  // If `busy === true` then another function is accessing `fd`.
-  // If `busy === false` then you're all clear to access.
-  let busy = false
-
-  // Each item should be a function that accepts no arguments.
-  // `release()` should be called as soon as `fd` access is complete.
-  // Items are processed FIFO even though `Array.shift()` is slow
-  const queue = []
-
-
-  // A function passed to `todo` will have exclusive access to positional 
-  // operations on `fd`, although append operations may still occur.
+  // > This is not safe on all platforms, no.
   //
-  // Any function passed to `todo()` absolutely *must* call `release()` when
-  // finished using `fd`, often as the first line in the `fs.foo()` callback.
-  const todo = (fn) => {
-    if (busy === true) {
-      queue.push(fn)
-    } else {
-      busy = true
-      fn()
-    }
-  }
 
-  const release = () => {
-    if (queue.length === 0) {
-      busy = false
-    } else {
-      queue.shift()()
-    }
-  }
+  const lock = new ReadWriteLock();
 
@@ -85,3 +52,3 @@ mkdirp(path.dirname(file), function () {
       offset.once(function (_offset) {
-        function onReady () {
+        lock.readLock((release) => {
           var max = ~~(_offset / block_size)
@@ -110,4 +77,3 @@ if(i > max)
           })
-        }
-        todo(onReady)
+        })
       })
@@ -148,3 +114,3 @@ },
 
-        function onReady () {
+        lock.writeLock((release) => {
           fs.write(fd, buf, 0, buf.length, pos, (err, written) => {
@@ -158,5 +124,3 @@ release()
           })
-        }
-
-        todo(onReady)
+        })
       })
@@ -163,0 +127,0 @@ },

package.json

 {
   "name": "aligned-block-file",
   "description": "",
-  "version": "1.2.1",
+  "version": "1.2.2",
   "homepage": "https://github.com/flumedb/aligned-block-file",
@@ -15,2 +15,3 @@ "repository": {
     "obv": "^0.0.1",
+    "rwlock": "^5.0.0",
     "uint48be": "^2.0.1"
@@ -17,0 +18,0 @@ },

New alerts

License Policy Violation

License

This package is not allowed per your license policy. Review the package's license to ensure compliance.

Found 1 instance in 1 package

Fixed alerts

License Policy Violation

License

This package is not allowed per your license policy. Review the package's license to ensure compliance.

Found 1 instance in 1 package

Worsened metrics

Total package byte prevSize

29073

decreased by-4.12%

Dependency count

6

increased by20%

Lines of code

802

decreased by-3.72%

Dependency changes

• + Addedrwlock@^5.0.0

• + Addedrwlock@5.0.0(transitive)