stream: augment BufferList.prototype

Move functions that deal with `BufferList` to `BufferList.prototype`. PR-URL: #18353 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Anatoli Papirovski <[email protected]> Reviewed-By: Ruben Bridgewater <[email protected]>
nodejs · Feb 1, 2018 · ccf64e5 · ccf64e5
1 parent 5898dc3
commit ccf64e5
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Showing 2 changed files with 87 additions and 90 deletions.
diff --git a/lib/_stream_readable.js b/lib/_stream_readable.js
@@ -987,106 +987,18 @@ function fromList(n, state) {
     if (state.decoder)
       ret = state.buffer.join('');
     else if (state.buffer.length === 1)
-      ret = state.buffer.head.data;
+      ret = state.buffer.first();
     else
       ret = state.buffer.concat(state.length);
     state.buffer.clear();
   } else {
     // read part of list
-    ret = fromListPartial(n, state.buffer, state.decoder);
+    ret = state.buffer.consume(n, state.decoder);
   }
 
   return ret;
 }
 
-// Extracts only enough buffered data to satisfy the amount requested.
-// This function is designed to be inlinable, so please take care when making
-// changes to the function body.
-function fromListPartial(n, list, hasStrings) {
-  var ret;
-  if (n < list.head.data.length) {
-    // slice is the same for buffers and strings
-    ret = list.head.data.slice(0, n);
-    list.head.data = list.head.data.slice(n);
-  } else if (n === list.head.data.length) {
-    // first chunk is a perfect match
-    ret = list.shift();
-  } else {
-    // result spans more than one buffer
-    ret = hasStrings ? copyFromBufferString(n, list) : copyFromBuffer(n, list);
-  }
-  return ret;
-}
-
-// Copies a specified amount of characters from the list of buffered data
-// chunks.
-// This function is designed to be inlinable, so please take care when making
-// changes to the function body.
-function copyFromBufferString(n, list) {
-  var p = list.head;
-  var c = 1;
-  var ret = p.data;
-  n -= ret.length;
-  while (p = p.next) {
-    const str = p.data;
-    const nb = (n > str.length ? str.length : n);
-    if (nb === str.length)
-      ret += str;
-    else
-      ret += str.slice(0, n);
-    n -= nb;
-    if (n === 0) {
-      if (nb === str.length) {
-        ++c;
-        if (p.next)
-          list.head = p.next;
-        else
-          list.head = list.tail = null;
-      } else {
-        list.head = p;
-        p.data = str.slice(nb);
-      }
-      break;
-    }
-    ++c;
-  }
-  list.length -= c;
-  return ret;
-}
-
-// Copies a specified amount of bytes from the list of buffered data chunks.
-// This function is designed to be inlinable, so please take care when making
-// changes to the function body.
-function copyFromBuffer(n, list) {
-  const ret = Buffer.allocUnsafe(n);
-  var p = list.head;
-  var c = 1;
-  p.data.copy(ret);
-  n -= p.data.length;
-  while (p = p.next) {
-    const buf = p.data;
-    const nb = (n > buf.length ? buf.length : n);
-    buf.copy(ret, ret.length - n, 0, nb);
-    n -= nb;
-    if (n === 0) {
-      if (nb === buf.length) {
-        ++c;
-        if (p.next)
-          list.head = p.next;
-        else
-          list.head = list.tail = null;
-      } else {
-        list.head = p;
-        p.data = buf.slice(nb);
-      }
-      break;
-    }
-    ++c;
-  }
-  list.length -= c;
-  return ret;
-}
-
 function endReadable(stream) {
   var state = stream._readableState;
 

diff --git a/lib/internal/streams/BufferList.js b/lib/internal/streams/BufferList.js
@@ -73,6 +73,91 @@ module.exports = class BufferList {
     return ret;
   }
 
+  // Consumes a specified amount of bytes or characters from the buffered data.
+  consume(n, hasStrings) {
+    var ret;
+    if (n < this.head.data.length) {
+      // `slice` is the same for buffers and strings.
+      ret = this.head.data.slice(0, n);
+      this.head.data = this.head.data.slice(n);
+    } else if (n === this.head.data.length) {
+      // First chunk is a perfect match.
+      ret = this.shift();
+    } else {
+      // Result spans more than one buffer.
+      ret = hasStrings ? this._getString(n) : this._getBuffer(n);
+    }
+    return ret;
+  }
+
+  first() {
+    return this.head.data;
+  }
+
+  // Consumes a specified amount of characters from the buffered data.
+  _getString(n) {
+    var p = this.head;
+    var c = 1;
+    var ret = p.data;
+    n -= ret.length;
+    while (p = p.next) {
+      const str = p.data;
+      const nb = (n > str.length ? str.length : n);
+      if (nb === str.length)
+        ret += str;
+      else
+        ret += str.slice(0, n);
+      n -= nb;
+      if (n === 0) {
+        if (nb === str.length) {
+          ++c;
+          if (p.next)
+            this.head = p.next;
+          else
+            this.head = this.tail = null;
+        } else {
+          this.head = p;
+          p.data = str.slice(nb);
+        }
+        break;
+      }
+      ++c;
+    }
+    this.length -= c;
+    return ret;
+  }
+
+  // Consumes a specified amount of bytes from the buffered data.
+  _getBuffer(n) {
+    const ret = Buffer.allocUnsafe(n);
+    var p = this.head;
+    var c = 1;
+    p.data.copy(ret);
+    n -= p.data.length;
+    while (p = p.next) {
+      const buf = p.data;
+      const nb = (n > buf.length ? buf.length : n);
+      buf.copy(ret, ret.length - n, 0, nb);
+      n -= nb;
+      if (n === 0) {
+        if (nb === buf.length) {
+          ++c;
+          if (p.next)
+            this.head = p.next;
+          else
+            this.head = this.tail = null;
+        } else {
+          this.head = p;
+          p.data = buf.slice(nb);
+        }
+        break;
+      }
+      ++c;
+    }
+    this.length -= c;
+    return ret;
+  }
+
   [inspect.custom]() {
     const obj = inspect({ length: this.length });
     return `${this.constructor.name} ${obj}`;