add minimalif

lib/script/interpreter.js

@@ -399,6 +399,13 @@ Interpreter.SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS = (1 << 11);
 // See BIP112 for details
 Interpreter.SCRIPT_VERIFY_CHECKSEQUENCEVERIFY = (1 << 10);
 
+//
+// Segwit script only: Require the argument of OP_IF/NOTIF to be exactly
+// 0x01 or empty vector
+//
+Interpreter.SCRIPT_VERIFY_MINIMALIF = (1 << 13);
+
+
 // Signature(s) must be empty vector if an CHECK(MULTI)SIG operation failed
 //
 Interpreter.SCRIPT_VERIFY_NULLFAIL = (1 << 14);
@@ -874,11 +881,25 @@ Interpreter.prototype.step = function() {
               this.errstr = 'SCRIPT_ERR_UNBALANCED_CONDITIONAL';
               return false;
             }
-            buf = this.stack.pop();
+
+            buf = this.stack[this.stack.length - 1];
+
+            if (this.flags & Interpreter.SCRIPT_VERIFY_MINIMALIF) {
+              buf = this.stack[this.stack.length - 1];
+              if (buf.length > 1) {
+                this.errstr = 'SCRIPT_ERR_MINIMALIF';
+                return false;
+              }
+              if (buf.length == 1 && buf[0]!=1) {
+                this.errstr = 'SCRIPT_ERR_MINIMALIF';
+                return false;
+              }
+            }
             fValue = Interpreter.castToBool(buf);
             if (opcodenum === Opcode.OP_NOTIF) {
               fValue = !fValue;
             }
+            this.stack.pop();
           }
           this.vfExec.push(fValue);
         }

test/script/interpreter.js

@@ -309,15 +309,13 @@ describe('Interpreter', function() {
       flags = flags | Interpreter.SCRIPT_VERIFY_CLEANSTACK;
     }
 
-console.log('[interpreter.js.311]', flagstr); //TODO
     if (flagstr.indexOf('WITNESS_PUBKEYTYPE') !== -1) {
-
-console.log('[interpreter.js.314] IN!'); //TODO
       flags = flags | Interpreter.SCRIPT_VERIFY_WITNESS_PUBKEYTYPE;
     }
+    if (flagstr.indexOf('MINIMALIF') !== -1) {
+      flags = flags | Interpreter.SCRIPT_VERIFY_MINIMALIF;
+    }
 
-console.log('ANTES XXX ', flags & Interpreter.SCRIPT_VERIFY_WITNESS_PUBKEYTYPE); //TODO
-console.log('[interpreter.js.320:flags:]',flags); //TODO
     return flags;
   };