Tighten up assignment instructions in formcalc.

The assignment operator can not be chained. This Cl removes the while
loop for assignments and changes it to an if(). We also can not have an
assignment inside ()'s so remove that option.

Bug: chromium:779349
Change-Id: I6934e18815f843ae8241023df6c03d8bbcd8168d
Reviewed-on: https://pdfium-review.googlesource.com/27350
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Ryan Harrison <rharrison@chromium.org>

1 files changed, 8 insertions, 28 deletions

diff --git a/xfa/fxfa/fm2js/cxfa_fmparser.cpp b/xfa/fxfa/fm2js/cxfa_fmparser.cpp
index 8baa59fb25..7add9888f8 100644
--- a/xfa/fxfa/fm2js/cxfa_fmparser.cpp
+++ b/xfa/fxfa/fm2js/cxfa_fmparser.cpp
@@ -15,7 +15,6 @@
 
 namespace {
 
-constexpr unsigned int kMaxAssignmentChainLength = 12;
 constexpr unsigned int kMaxParseDepth = 1250;
 constexpr unsigned int kMaxPostExpressions = 16384;
 
@@ -223,12 +222,12 @@ std::unique_ptr<CXFA_FMExpression> CXFA_FMParser::ParseDeclarationExpression() {
   if (!NextToken())
     return nullptr;
 
-  std::unique_ptr<CXFA_FMExpression> expr;
+  std::unique_ptr<CXFA_FMSimpleExpression> expr;
   if (m_token.m_type == TOKassign) {
     if (!NextToken())
       return nullptr;
 
-    expr = ParseExpExpression();
+    expr = ParseSimpleExpression();
     if (!expr)
       return nullptr;
   }
@@ -253,17 +252,15 @@ std::unique_ptr<CXFA_FMExpression> CXFA_FMParser::ParseExpExpression() {
   std::unique_ptr<CXFA_FMSimpleExpression> pExp1 = ParseSimpleExpression();
   if (!pExp1)
     return nullptr;
-  int level = 1;
-  while (m_token.m_type == TOKassign) {
+
+  if (m_token.m_type == TOKassign) {
     if (!NextToken())
       return nullptr;
-    std::unique_ptr<CXFA_FMSimpleExpression> pExp2 = ParseLogicalOrExpression();
+
+    std::unique_ptr<CXFA_FMSimpleExpression> pExp2 = ParseSimpleExpression();
     if (!pExp2)
       return nullptr;
-    if (level++ == kMaxAssignmentChainLength) {
-      m_error = true;
-      return nullptr;
-    }
+
     pExp1 = pdfium::MakeUnique<CXFA_FMAssignExpression>(
         line, TOKassign, std::move(pExp1), std::move(pExp2));
   }
@@ -913,27 +910,10 @@ std::unique_ptr<CXFA_FMSimpleExpression> CXFA_FMParser::ParseParenExpression() {
     return nullptr;
   }
 
-  uint32_t line = m_lexer->GetCurrentLine();
-  std::unique_ptr<CXFA_FMSimpleExpression> pExp1 = ParseLogicalOrExpression();
+  std::unique_ptr<CXFA_FMSimpleExpression> pExp1 = ParseSimpleExpression();
   if (!pExp1)
     return nullptr;
 
-  int level = 1;
-  while (m_token.m_type == TOKassign) {
-    if (!NextToken())
-      return nullptr;
-
-    std::unique_ptr<CXFA_FMSimpleExpression> pExp2 = ParseLogicalOrExpression();
-    if (!pExp2)
-      return nullptr;
-    if (level++ == kMaxAssignmentChainLength) {
-      m_error = true;
-      return nullptr;
-    }
-
-    pExp1 = pdfium::MakeUnique<CXFA_FMAssignExpression>(
-        line, TOKassign, std::move(pExp1), std::move(pExp2));
-  }
   if (!CheckThenNext(TOKrparen))
     return nullptr;
   return pExp1;