Add support for entity-matching in domain= filter option

Related issue:
- uBlockOrigin/uBlock-issues#1008

This commit adds support entity-matching in the filter
option `domain=`. Example:

    pattern$domain=google.*

The `*` above is meant to match any suffix from the Public
Suffix List. The semantic is exactly the same as the
already existing entity-matching support in static
extended filtering:

- https://github.com/gorhill/uBlock/wiki/Static-filter-syntax#entity

Additionally, in this commit:

Fix cases where "just-origin" filters of the form `|http*://`
were erroneously normalized to `|http://`. The proper
normalization of `|http*://` is `*`.

Add support to store hostname strings into the character
buffer of a hntrie container. As of commit time, there are
5,544 instances of FilterOriginHit, and 732 instances of
FilterOriginMiss, which filters require storing/matching a
single hostname string. Those strings are now stored in the
character buffer of the already existing origin-related
 hntrie container. (The same approach is used for plain
patterns which are not part of a bidi-trie.)

Author: gorhill

src/js/background.js

@@ -138,8 +138,8 @@ const µBlock = (( ) => { // jshint ignore:line
 
         // Read-only
         systemSettings: {
-            compiledMagic: 27,  // Increase when compiled format changes
-            selfieMagic: 26,    // Increase when selfie format changes
+            compiledMagic: 28,  // Increase when compiled format changes
+            selfieMagic: 28,    // Increase when selfie format changes
         },
 
         // https://github.com/uBlockOrigin/uBlock-issues/issues/759#issuecomment-546654501

src/js/hntrie.js

@@ -407,6 +407,49 @@ const HNTrieContainer = class {
         return true;
     }
 
+    // The following *Hostname() methods can be used to store hostname strings
+    // outside the trie. This is useful to store/match hostnames which are
+    // not part of a collection, and yet still benefit from storing the strings
+    // into a trie container's character buffer.
+    // TODO: WASM version of matchesHostname()
+
+    storeHostname(hn) {
+        let n = hn.length;
+        if ( n > 255 ) {
+            hn = hn.slice(-255);
+            n = 255;
+        }
+        if ( (this.buf.length - this.buf32[CHAR1_SLOT]) < n ) {
+            this.growBuf(0, n);
+        }
+        const offset = this.buf32[CHAR1_SLOT];
+        this.buf32[CHAR1_SLOT] = offset + n;
+        const buf8 = this.buf;
+        for ( let i = 0; i < n; i++ ) {
+            buf8[offset+i] = hn.charCodeAt(i);
+        }
+        return offset - this.buf32[CHAR0_SLOT];
+    }
+
+    extractHostname(i, n) {
+        const textDecoder = new TextDecoder();
+        const offset = this.buf32[CHAR0_SLOT] + i;
+        return textDecoder.decode(this.buf.subarray(offset, offset + n));
+    }
+
+    matchesHostname(hn, i, n) {
+        this.setNeedle(hn);
+        const buf8 = this.buf;
+        const hr = buf8[255];
+        if ( n > hr ) { return false; }
+        const hl = hr - n;
+        const nl = this.buf32[CHAR0_SLOT] + i;
+        for ( let j = 0; j < n; j++ ) {
+            if ( buf8[nl+j] !== buf8[hl+j] ) { return false; }
+        }
+        return n === hr || hn.charCodeAt(hl-1) === 0x2E /* '.' */;
+    }
+
     async enableWASM() {
         if ( typeof WebAssembly !== 'object' ) { return false; }
         if ( this.wasmMemory instanceof WebAssembly.Memory ) { return true; }