From 9f7e385a5c15abdf9737366bcf69c00396e6a938 Mon Sep 17 00:00:00 2001
From: Raymond Hill <rhill@raymondhill.net>
Date: Fri, 23 Aug 2019 11:30:10 -0400
Subject: [PATCH] Code review fix re. max string length in bidi-trie

Related commit:
- fb4e94f92c11d8c465b423dae1a18a696efe10a8

A bidi-trie can't store strings longer than 255 characters
because the string segment lengths are encoded into a single
byte. This commit ensures only strings smaller than
256 characters are stored in the bidi-tries.
---
 src/js/static-net-filtering.js | 37 ++++++++++++++++++++--------------
 src/js/strie.js                |  4 ++--
 2 files changed, 24 insertions(+), 17 deletions(-)

diff --git a/src/js/static-net-filtering.js b/src/js/static-net-filtering.js
index 2fe5b8a2c..04e2fa3bb 100644
--- a/src/js/static-net-filtering.js
+++ b/src/js/static-net-filtering.js
@@ -333,7 +333,9 @@ const FilterPlain = class {
     }
 
     addToTrie(trie) {
+        if ( this.s.length > 255 ) { return false; }
         trie.add(this.s, this.tokenBeg);
+        return true;
     }
 
     static compile(details) {
@@ -351,7 +353,9 @@ const FilterPlain = class {
     }
 
     static addToTrie(args, trie) {
+        if ( args[1].length > 255 ) { return false; }
         trie.add(args[1], args[2]);
+        return true;
     }
 };
 
@@ -547,7 +551,9 @@ const FilterPlainHnAnchored = class {
     }
 
     addToTrie(trie) {
+        if ( this.s.length > 255 ) { return false; }
         trie.add(this.s, this.tokenBeg);
+        return true;
     }
 
     static compile(details) {
@@ -562,7 +568,9 @@ const FilterPlainHnAnchored = class {
     }
 
     static addToTrie(args, trie) {
+        if ( args[1].length > 255 ) { return false; }
         trie.add(args[1], args[2]);
+        return true;
     }
 };
 
@@ -1644,25 +1652,24 @@ const FilterBucket = class {
         const fclass = filterClasses[fdata[0]];
         if ( fclass.trieableId === 0 ) {
             if ( this.plainTrie !== null ) {
-                return fclass.addToTrie(fdata, this.plainTrie);
-            }
-            if ( this.plainCount === 3 ) {
+                if ( fclass.addToTrie(fdata, this.plainTrie) ) { return; }
+            } else if ( this.plainCount < 3 ) {
+                this.plainCount += 1;
+            } else {
                 this.plainTrie = FilterBucket.trieContainer.createOne();
                 this._transferTrieable(0, this.plainTrie);
-                return fclass.addToTrie(fdata, this.plainTrie);
+                if ( fclass.addToTrie(fdata, this.plainTrie) ) { return; }
             }
-            this.plainCount += 1;
-        }
-        if ( fclass.trieableId === 1 ) {
+        } else if ( fclass.trieableId === 1 ) {
             if ( this.plainHnAnchoredTrie !== null ) {
-                return fclass.addToTrie(fdata, this.plainHnAnchoredTrie);
-            }
-            if ( this.plainHnAnchoredCount === 3 ) {
+                if ( fclass.addToTrie(fdata, this.plainHnAnchoredTrie) ) { return; }
+            } else if ( this.plainHnAnchoredCount < 3 ) {
+                this.plainHnAnchoredCount += 1;
+            } else {
                 this.plainHnAnchoredTrie = FilterBucket.trieContainer.createOne();
                 this._transferTrieable(1, this.plainHnAnchoredTrie);
-                return fclass.addToTrie(fdata, this.plainHnAnchoredTrie);
+                if ( fclass.addToTrie(fdata, this.plainHnAnchoredTrie) ) { return; }
             }
-            this.plainHnAnchoredCount += 1;
         }
         this.filters.push(filterFromCompiledData(fdata));
     }
@@ -1736,8 +1743,8 @@ const FilterBucket = class {
         let i = filters.length;
         while ( i-- ) {
             const f = filters[i];
-            if ( f.trieableId !== trieableId || f.s.length > 255 ) { continue; }
-            f.addToTrie(trie);
+            if ( f.trieableId !== trieableId ) { continue; }
+            if ( f.addToTrie(trie) === false ) { continue; }
             filters.splice(i, 1);
         }
     }
@@ -1764,7 +1771,7 @@ const FilterBucket = class {
     }
 
     static optimize() {
-        const trieDetails = this.trieContainer.optimize();
+        const trieDetails = FilterBucket.trieContainer.optimize();
         vAPI.localStorage.setItem(
             'FilterBucket.trieDetails',
             JSON.stringify(trieDetails)
diff --git a/src/js/strie.js b/src/js/strie.js
index 3d1824987..88ec4badc 100644
--- a/src/js/strie.js
+++ b/src/js/strie.js
@@ -244,9 +244,9 @@ const SEGMENT_INFO = 2;
         // grow buffer if needed
         if (
             (this.buf32[CHAR0_SLOT] - this.buf32[TRIE1_SLOT]) < MIN_FREE_CELL_BYTE_LENGTH ||
-            (this.buf.length - this.buf32[CHAR1_SLOT]) < aR
+            (this.buf.length - this.buf32[CHAR1_SLOT]) < 256
         ) {
-            this.growBuf(MIN_FREE_CELL_BYTE_LENGTH, aR);
+            this.growBuf(MIN_FREE_CELL_BYTE_LENGTH, 256);
         }
         const buf32 = this.buf32;
         let icell = iroot;