memory footprint work - avoid read-only blacklist data duplication

Author: gorhill

js/background.js

@@ -21,182 +21,6 @@
 
 /******************************************************************************/
 
-// unpacked:
-//      map[hostname] = true/false
-// packed
-//      map[tld].[leftover.length] = haystack on which to perform binary search
-//
-// Idea for mapping according to length inspired from reading the section
-// "String-based Binary Search" @ http://ejohn.org/blog/revised-javascript-dictionary-search/
-// Except for the core binary search I reused my own faithful version which has
-// served me well over time.
-//
-// Figuratively speaking, this means when looking up a hostname, aka the needle,
-// the TLD of the hostname tells us on which farm we must go, and the length
-// of the hostname minus TLD tells us which haystack on that farm with must
-// look into.
-//
-// Before, with quickIndexOf(), I was binary-searching one big ass haystack,
-// now, using very easy to compute hostname patterns, I lookup a smaller
-// haystack before binary-searching. But I appreciate especially the reduced
-// memory footprint -- through the removal of all redundant information within
-// a single haystack.
-//
-// Stats:
-// Using Object for farm: sizeof(blacklistReadonly): 1,050,028
-// Using Array for farm: sizeof(blacklistReadonly): 1,050,640
-// So I will stick to using an Array because:
-// http://jsperf.com/performance-of-array-vs-object/49
-
-var blacklistReadonly = {
-    packed: {},
-    unpacked: null,
-
-    unpack: function() {
-        var unpacked = this.unpacked;
-        if ( unpacked ) {
-            return unpacked;
-        }
-        unpacked = {};
-        this._unpack(unpacked, '');
-        this.packed = null;
-        this.unpacked = unpacked;
-        return unpacked;
-    },
-
-    pack: function() {
-        var packed = this.packed;
-        if ( packed ) {
-            return packed;
-        }
-        packed = {};
-        var unpacked = this.unpacked;
-        var hostnames = Object.keys(unpacked);
-        var iHostname = hostnames.length;
-        var hostname, idot, tld, hnPrefix;
-        var len, farm, haystack;
-        while ( iHostname-- ) {
-            hostname = hostnames[iHostname];
-            idot = hostname.lastIndexOf('.');
-            hnPrefix = hostname.slice(0, idot);
-            tld = hostname.slice(idot+1);
-            len = hnPrefix.length;
-            if ( !packed[tld] ) {
-                packed[tld] = [];
-            }
-            farm = packed[tld];
-            if ( !farm[len] ) {
-                farm[len] = {};
-            }
-            haystack = farm[len];
-            haystack[hnPrefix] = true;
-        }
-        var tldKeys = Object.keys(packed);
-        var iTld = tldKeys.length;
-        while ( iTld-- ) {
-            tld = tldKeys[iTld];
-            farm = packed[tld];
-            len = farm.length;
-            while ( len-- ) {
-                if ( farm[len] !== undefined ) {
-                    farm[len] = Object.keys(farm[len]).sort().join('');
-                }
-            }
-        }
-        this.unpacked = null;
-        this.packed = packed;
-        return packed;
-    },
-
-    toFilters: function(des) {
-        var unpacked = this.unpacked;
-        if ( unpacked ) {
-            var hostnames = Object.keys(unpacked);
-            var i = hostnames.length;
-            while ( i-- ) {
-                des['*/' + hostnames[i]] = true;
-            }
-            return;
-        }
-        this._unpack(des, '*/');
-    },
-
-    addOne: function(hostname) {
-        var unpacked = this.unpacked || this.unpack();
-        unpacked[hostname] = true;
-    },
-
-    addMany: function(s) {
-        var unpacked = this.unpacked || this.unpack();
-        var hostnames = s.split(/\s+/);
-        var i = hostnames.length;
-        var hostname;
-        while ( i-- ) {
-            hostname = hostnames[i];
-            if ( hostname.length ) {
-                unpacked[hostname.toLowerCase()] = true;
-            }
-        }
-    },
-
-    find: function(hostname) {
-        var packed = this.packed || this.pack();
-        var idot = hostname.lastIndexOf('.');
-        var tld = hostname.slice(idot+1);
-        var farm = packed[tld];
-        if ( !farm ) {
-            return false;
-        }
-        var hnPrefix = hostname.slice(0, idot);
-        var len = hnPrefix.length;
-        var haystack = farm[len];
-        if ( !haystack ) {
-            return false;
-        }
-        var left = 0;
-        var right = Math.round(haystack.length / len);
-        var i, needle;
-        while ( left < right ) {
-            i = left + right >> 1;
-            needle = haystack.substr(i * len, len);
-            if ( hnPrefix < needle ) {
-                right = i;
-            } else if ( hnPrefix > needle ) {
-                left = i + 1;
-            } else {
-                return true;
-            }
-        }
-        return false;
-    },
-
-    // this exists only in order to avoid code duplication
-    _unpack: function(des, prefix) {
-        var packed = this.packed;
-        var tlds = Object.keys(packed);
-        var iTld = tlds.length;
-        var tld, farm, len;
-        var haystack, iStraw;
-        while ( iTld-- ) {
-            tld = tlds[iTld];
-            farm = packed[tld];
-            len = farm.length;
-            while ( len-- ) {
-                haystack = farm[len];
-                if ( haystack ) {
-                    iStraw = haystack.length;
-                    while ( iStraw ) {
-                        iStraw -= len;
-                        des[prefix + haystack.substr(iStraw, len) + '.' + tld] = true;
-                    }
-                }
-            }
-        }
-    }
-};
-
-/******************************************************************************/
-
 var HTTPSB = {
     manifest: chrome.runtime.getManifest(),
 
@@ -244,14 +68,14 @@ var HTTPSB = {
     // effective lists
     whitelist: { },
     blacklist: { '*/*': true },
-    graylist: { },  // this will override preset blacklists
+    graylist: { },
     // user lists
     whitelistUser: {},
     blacklistUser: {},
     graylistUser: {}, // this will override preset blacklists
 
     // Current entries from remote blacklists
-    blacklistReadonly: blacklistReadonly,
+    blacklistReadonly: {},
 
     // https://github.com/gorhill/httpswitchboard/issues/19
     excludeRegex: /^https?:\/\/chrome\.google\.com\/(extensions|webstore)/,