Move RowSnapshot into a module Preparation for future changes

Signed-off-by: Jesús <heckyel@hyperbola.info>

1 files changed, 58 insertions, 0 deletions

diff --git a/lib/RowSnapshot.jsm b/lib/RowSnapshot.jsm
new file mode 100644
index 0000000..edc6bc9
--- /dev/null
+++ b/lib/RowSnapshot.jsm
@@ -0,0 +1,58 @@
+/*******************************************************************************
+
+    ηMatrix - a browser extension to black/white list requests.
+    Copyright (C) 2014-2019 Raymond Hill
+    Copyright (C) 2019-2020 Alessio Vanni
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://gitlab.com/vannilla/ematrix
+    uMatrix Home: https://github.com/gorhill/uMatrix
+*/
+
+'use strict';
+
+// Apparently, for this specific data structure using a constructor is
+// faster than an object literal.
+// I don't really believe it, but let's keep things as they are.
+// Now a module to keep things more organized (might make things slower.)
+
+var EXPORTED_SYMBOLS = ['RowSnapshot'];
+
+var RowSnapshot = function (matrix, src, dest, domain) {
+    this.domain = domain;
+    this.temporary = matrix.tMatrix.evaluateRowZXY(src, dest);
+    this.permanent = matrix.pMatrix.evaluateRowZXY(src, dest);
+    this.counts = RowSnapshot.counts(matrix).slice();
+    this.totals = RowSnapshot.counts(matrix).slice();
+};
+
+RowSnapshot.memoizedCounts = undefined;
+
+RowSnapshot.counts = function (matrix) {
+    if (RowSnapshot.memoizedCounts !== undefined) {
+	return RowSnapshot.memoizedCounts;
+    }
+
+    let aa = [];
+    let n = matrix.Matrix.columnHeaderIndices.size;
+
+    for (let i=0; i<n; ++i) {
+	aa[i] = 0;
+    }
+
+    RowSnapshot.memoizedCounts = aa;
+
+    return aa;
+};