Consistently apply JS size check

This CL makes the use of CXFA_IsTooBig consistent and universal across
all of the ToJavascript and related methods. Previously this method
was only applied in some calls. It is now being tested as a 
precondition and postcondition on every call and as a post condition 
for the entire translation process.

There are some size checks within methods that potentially generate
large amounts of JS that have been left in.

BUG=chromium:752920

Change-Id: I1a8bfe21e0a17c2e47592fc6017060243674f1bc
Reviewed-on: https://pdfium-review.googlesource.com/16812
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

1 files changed, 46 insertions, 53 deletions

diff --git a/xfa/fxfa/fm2js/cxfa_fmexpression.cpp b/xfa/fxfa/fm2js/cxfa_fmexpression.cpp
index 661ce42789..759a875b8d 100644
--- a/xfa/fxfa/fm2js/cxfa_fmexpression.cpp
+++ b/xfa/fxfa/fm2js/cxfa_fmexpression.cpp
@@ -9,6 +9,7 @@
 #include <utility>
 
 #include "core/fxcrt/cfx_widetextbuf.h"
+#include "xfa/fxfa/fm2js/cxfa_fmsimpleexpression.h"
 #include "xfa/fxfa/fm2js/cxfa_fmtojavascriptdepth.h"
 
 namespace {
@@ -32,12 +33,12 @@ CXFA_FMExpression::CXFA_FMExpression(uint32_t line, XFA_FM_EXPTYPE type)
 
 bool CXFA_FMExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  return depthManager.IsWithinMaxDepth();
+  return !CXFA_IsTooBig(javascript) && depthManager.IsWithinMaxDepth();
 }
 
 bool CXFA_FMExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  return depthManager.IsWithinMaxDepth();
+  return !CXFA_IsTooBig(javascript) && depthManager.IsWithinMaxDepth();
 }
 
 CXFA_FMFunctionDefinition::CXFA_FMFunctionDefinition(
@@ -56,12 +57,12 @@ CXFA_FMFunctionDefinition::~CXFA_FMFunctionDefinition() {}
 
 bool CXFA_FMFunctionDefinition::ToJavaScript(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   if (m_isGlobal && m_pExpressions.empty()) {
     javascript << L"// comments only";
-    return true;
+    return !CXFA_IsTooBig(javascript);
   }
   if (m_isGlobal) {
     javascript << L"(\n";
@@ -98,7 +99,8 @@ bool CXFA_FMFunctionDefinition::ToJavaScript(CFX_WideTextBuf& javascript) {
       ret = expr->ToImpliedReturnJS(javascript);
     else
       ret = expr->ToJavaScript(javascript);
-    if (!ret || CXFA_IsTooBig(javascript))
+
+    if (!ret)
       return false;
   }
   javascript << L"return ";
@@ -114,12 +116,12 @@ bool CXFA_FMFunctionDefinition::ToJavaScript(CFX_WideTextBuf& javascript) {
   if (m_isGlobal) {
     javascript << L").call(this);\n";
   }
-  return true;
+  return !CXFA_IsTooBig(javascript);
 }
 
-bool CXFA_FMFunctionDefinition::ToImpliedReturnJS(CFX_WideTextBuf&) {
+bool CXFA_FMFunctionDefinition::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  return depthManager.IsWithinMaxDepth();
+  return !CXFA_IsTooBig(javascript) && depthManager.IsWithinMaxDepth();
 }
 
 CXFA_FMVarExpression::CXFA_FMVarExpression(
@@ -134,7 +136,7 @@ CXFA_FMVarExpression::~CXFA_FMVarExpression() {}
 
 bool CXFA_FMVarExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << L"var ";
@@ -157,12 +159,12 @@ bool CXFA_FMVarExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   } else {
     javascript << L"\"\";\n";
   }
-  return true;
+  return !CXFA_IsTooBig(javascript);
 }
 
 bool CXFA_FMVarExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << L"var ";
@@ -189,7 +191,7 @@ bool CXFA_FMVarExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   javascript << L" = ";
   javascript << tempName;
   javascript << L";\n";
-  return true;
+  return !CXFA_IsTooBig(javascript);
 }
 
 CXFA_FMExpExpression::CXFA_FMExpExpression(
@@ -202,7 +204,7 @@ CXFA_FMExpExpression::~CXFA_FMExpExpression() {}
 
 bool CXFA_FMExpExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   bool ret = m_pExpression->ToJavaScript(javascript);
@@ -213,7 +215,7 @@ bool CXFA_FMExpExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
 
 bool CXFA_FMExpExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   if (m_pExpression->GetOperatorToken() == TOKassign)
@@ -231,7 +233,7 @@ bool CXFA_FMExpExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
     if (!m_pExpression->ToJavaScript(javascript))
       return false;
     javascript << L");\n";
-    return true;
+    return !CXFA_IsTooBig(javascript);
   }
 
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
@@ -239,7 +241,7 @@ bool CXFA_FMExpExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   if (!m_pExpression->ToJavaScript(javascript))
     return false;
   javascript << L";\n";
-  return true;
+  return !CXFA_IsTooBig(javascript);
 }
 
 CXFA_FMBlockExpression::CXFA_FMBlockExpression(
@@ -252,21 +254,21 @@ CXFA_FMBlockExpression::~CXFA_FMBlockExpression() {}
 
 bool CXFA_FMBlockExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << L"{\n";
   for (const auto& expr : m_ExpressionList) {
-    if (!expr->ToJavaScript(javascript) || CXFA_IsTooBig(javascript))
+    if (!expr->ToJavaScript(javascript))
       return false;
   }
   javascript << L"}\n";
-  return true;
+  return !CXFA_IsTooBig(javascript);
 }
 
 bool CXFA_FMBlockExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << L"{\n";
@@ -276,11 +278,12 @@ bool CXFA_FMBlockExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
       ret = expr->ToImpliedReturnJS(javascript);
     else
       ret = expr->ToJavaScript(javascript);
-    if (!ret || CXFA_IsTooBig(javascript))
+
+    if (!ret)
       return false;
   }
   javascript << L"}\n";
-  return true;
+  return !CXFA_IsTooBig(javascript);
 }
 
 CXFA_FMDoExpression::CXFA_FMDoExpression(
@@ -292,7 +295,7 @@ CXFA_FMDoExpression::~CXFA_FMDoExpression() {}
 
 bool CXFA_FMDoExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   return m_pList->ToJavaScript(javascript);
@@ -300,7 +303,7 @@ bool CXFA_FMDoExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
 
 bool CXFA_FMDoExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   return m_pList->ToImpliedReturnJS(javascript);
@@ -320,7 +323,7 @@ CXFA_FMIfExpression::~CXFA_FMIfExpression() {}
 
 bool CXFA_FMIfExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << L"if (";
@@ -360,7 +363,7 @@ bool CXFA_FMIfExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
 
 bool CXFA_FMIfExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
@@ -403,12 +406,12 @@ CXFA_FMLoopExpression::~CXFA_FMLoopExpression() {}
 
 bool CXFA_FMLoopExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  return depthManager.IsWithinMaxDepth();
+  return !CXFA_IsTooBig(javascript) && depthManager.IsWithinMaxDepth();
 }
 
-bool CXFA_FMLoopExpression::ToImpliedReturnJS(CFX_WideTextBuf&) {
+bool CXFA_FMLoopExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  return depthManager.IsWithinMaxDepth();
+  return !CXFA_IsTooBig(javascript) && depthManager.IsWithinMaxDepth();
 }
 
 CXFA_FMWhileExpression::CXFA_FMWhileExpression(
@@ -423,7 +426,7 @@ CXFA_FMWhileExpression::~CXFA_FMWhileExpression() {}
 
 bool CXFA_FMWhileExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << L"while (";
@@ -440,7 +443,7 @@ bool CXFA_FMWhileExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
 
 bool CXFA_FMWhileExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
@@ -464,24 +467,24 @@ CXFA_FMBreakExpression::~CXFA_FMBreakExpression() {}
 
 bool CXFA_FMBreakExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
   javascript << L" = 0;\n";
   javascript << L"break;\n";
-  return true;
+  return !CXFA_IsTooBig(javascript);
 }
 
 bool CXFA_FMBreakExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
   javascript << L" = 0;\n";
   javascript << L"break;\n";
-  return true;
+  return !CXFA_IsTooBig(javascript);
 }
 
 CXFA_FMContinueExpression::CXFA_FMContinueExpression(uint32_t line)
@@ -491,24 +494,24 @@ CXFA_FMContinueExpression::~CXFA_FMContinueExpression() {}
 
 bool CXFA_FMContinueExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
   javascript << L" = 0;\n";
   javascript << L"continue;\n";
-  return true;
+  return !CXFA_IsTooBig(javascript);
 }
 
 bool CXFA_FMContinueExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
   javascript << L" = 0;\n";
   javascript << L"continue;\n";
-  return true;
+  return !CXFA_IsTooBig(javascript);
 }
 
 CXFA_FMForExpression::CXFA_FMForExpression(
@@ -531,7 +534,7 @@ CXFA_FMForExpression::~CXFA_FMForExpression() {}
 
 bool CXFA_FMForExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << L"{\nvar ";
@@ -554,8 +557,6 @@ bool CXFA_FMForExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
     return false;
   javascript << L"); ";
   javascript << tempVariant;
-  if (CXFA_IsTooBig(javascript))
-    return false;
 
   javascript << (m_bDirection ? kLessEqual : kGreaterEqual);
   javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
@@ -574,8 +575,6 @@ bool CXFA_FMForExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
     if (!m_pStep->ToJavaScript(javascript))
       return false;
     javascript << L")";
-    if (CXFA_IsTooBig(javascript))
-      return false;
   } else {
     javascript << L"1";
   }
@@ -588,7 +587,7 @@ bool CXFA_FMForExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
 
 bool CXFA_FMForExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
@@ -613,8 +612,6 @@ bool CXFA_FMForExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
     return false;
   javascript << L"); ";
   javascript << tempVariant;
-  if (CXFA_IsTooBig(javascript))
-    return false;
 
   javascript << (m_bDirection ? kLessEqual : kGreaterEqual);
   javascript << XFA_FM_EXPTypeToString(GETFMVALUE);
@@ -660,7 +657,7 @@ CXFA_FMForeachExpression::~CXFA_FMForeachExpression() {}
 
 bool CXFA_FMForeachExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << L"{\n";
@@ -685,8 +682,6 @@ bool CXFA_FMForeachExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
       return false;
     if (expr != m_pAccessors.back())
       javascript << L", ";
-    if (CXFA_IsTooBig(javascript))
-      return false;
   }
   javascript << L");\n";
   javascript << L"var ";
@@ -719,7 +714,7 @@ bool CXFA_FMForeachExpression::ToJavaScript(CFX_WideTextBuf& javascript) {
 
 bool CXFA_FMForeachExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
   CXFA_FMToJavaScriptDepth depthManager;
-  if (!depthManager.IsWithinMaxDepth())
+  if (CXFA_IsTooBig(javascript) || !depthManager.IsWithinMaxDepth())
     return false;
 
   javascript << RUNTIMEFUNCTIONRETURNVALUE;
@@ -745,8 +740,6 @@ bool CXFA_FMForeachExpression::ToImpliedReturnJS(CFX_WideTextBuf& javascript) {
       return false;
     if (expr != m_pAccessors.back())
       javascript << L", ";
-    if (CXFA_IsTooBig(javascript))
-      return false;
   }
   javascript << L");\n";
   javascript << L"var ";