Use UnownedPtr to check CFX_*StringC lifetimeschromium/3104

Change interform to avoid temp StringC with dangling ptr.

Change-Id: I8d8659973bcdf2cdbcaa6efa6012e4acce5f1604
Reviewed-on: https://pdfium-review.googlesource.com/5571
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

2 files changed, 26 insertions, 22 deletions

diff --git a/core/fxcrt/cfx_string_c_template.h b/core/fxcrt/cfx_string_c_template.h
index 75c2be0efc..3a0ad74c08 100644
--- a/core/fxcrt/cfx_string_c_template.h
+++ b/core/fxcrt/cfx_string_c_template.h
@@ -11,6 +11,7 @@
 #include <type_traits>
 #include <vector>
 
+#include "core/fxcrt/cfx_unowned_ptr.h"
 #include "core/fxcrt/fx_system.h"
 #include "third_party/base/stl_util.h"
 
@@ -75,22 +76,23 @@ class CFX_StringCTemplate {
   }
 
   const_iterator begin() const {
-    return reinterpret_cast<const CharType*>(m_Ptr);
+    return reinterpret_cast<const CharType*>(m_Ptr.Get());
   }
   const_iterator end() const {
-    return m_Ptr ? reinterpret_cast<const CharType*>(m_Ptr) + m_Length
+    return m_Ptr ? reinterpret_cast<const CharType*>(m_Ptr.Get()) + m_Length
                  : nullptr;
   }
 
   bool operator==(const CharType* ptr) const {
     return FXSYS_len(ptr) == m_Length &&
-           FXSYS_cmp(ptr, reinterpret_cast<const CharType*>(m_Ptr), m_Length) ==
-               0;
+           FXSYS_cmp(ptr, reinterpret_cast<const CharType*>(m_Ptr.Get()),
+                     m_Length) == 0;
   }
   bool operator==(const CFX_StringCTemplate& other) const {
     return other.m_Length == m_Length &&
-           FXSYS_cmp(reinterpret_cast<const CharType*>(other.m_Ptr),
-                     reinterpret_cast<const CharType*>(m_Ptr), m_Length) == 0;
+           FXSYS_cmp(reinterpret_cast<const CharType*>(other.m_Ptr.Get()),
+                     reinterpret_cast<const CharType*>(m_Ptr.Get()),
+                     m_Length) == 0;
   }
   bool operator!=(const CharType* ptr) const { return !(*this == ptr); }
   bool operator!=(const CFX_StringCTemplate& other) const {
@@ -104,28 +106,28 @@ class CFX_StringCTemplate {
     uint32_t strid = 0;
     FX_STRSIZE size = std::min(4, m_Length - start_pos);
     for (FX_STRSIZE i = 0; i < size; i++)
-      strid = strid * 256 + m_Ptr[start_pos + i];
+      strid = strid * 256 + m_Ptr.Get()[start_pos + i];
 
     return strid << ((4 - size) * 8);
   }
 
-  const UnsignedType* raw_str() const { return m_Ptr; }
+  const UnsignedType* raw_str() const { return m_Ptr.Get(); }
   const CharType* c_str() const {
-    return reinterpret_cast<const CharType*>(m_Ptr);
+    return reinterpret_cast<const CharType*>(m_Ptr.Get());
   }
 
   FX_STRSIZE GetLength() const { return m_Length; }
   bool IsEmpty() const { return m_Length == 0; }
 
-  UnsignedType GetAt(FX_STRSIZE index) const { return m_Ptr[index]; }
+  UnsignedType GetAt(FX_STRSIZE index) const { return m_Ptr.Get()[index]; }
   CharType CharAt(FX_STRSIZE index) const {
-    return static_cast<CharType>(m_Ptr[index]);
+    return static_cast<CharType>(m_Ptr.Get()[index]);
   }
 
   FX_STRSIZE Find(CharType ch) const {
-    const UnsignedType* found = reinterpret_cast<const UnsignedType*>(
-        FXSYS_chr(reinterpret_cast<const CharType*>(m_Ptr), ch, m_Length));
-    return found ? found - m_Ptr : -1;
+    const UnsignedType* found = reinterpret_cast<const UnsignedType*>(FXSYS_chr(
+        reinterpret_cast<const CharType*>(m_Ptr.Get()), ch, m_Length));
+    return found ? found - m_Ptr.Get() : -1;
   }
 
   CFX_StringCTemplate Mid(FX_STRSIZE index, FX_STRSIZE count = -1) const {
@@ -136,14 +138,14 @@ class CFX_StringCTemplate {
     if (count < 0 || count > m_Length - index)
       count = m_Length - index;
 
-    return CFX_StringCTemplate(m_Ptr + index, count);
+    return CFX_StringCTemplate(m_Ptr.Get() + index, count);
   }
 
   CFX_StringCTemplate Left(FX_STRSIZE count) const {
     if (count <= 0)
       return CFX_StringCTemplate();
 
-    return CFX_StringCTemplate(m_Ptr, std::min(count, m_Length));
+    return CFX_StringCTemplate(m_Ptr.Get(), std::min(count, m_Length));
   }
 
   CFX_StringCTemplate Right(FX_STRSIZE count) const {
@@ -151,20 +153,22 @@ class CFX_StringCTemplate {
       return CFX_StringCTemplate();
 
     count = std::min(count, m_Length);
-    return CFX_StringCTemplate(m_Ptr + m_Length - count, count);
+    return CFX_StringCTemplate(m_Ptr.Get() + m_Length - count, count);
   }
 
-  const UnsignedType& operator[](size_t index) const { return m_Ptr[index]; }
+  const UnsignedType& operator[](size_t index) const {
+    return m_Ptr.Get()[index];
+  }
 
   bool operator<(const CFX_StringCTemplate& that) const {
-    int result = FXSYS_cmp(reinterpret_cast<const CharType*>(m_Ptr),
-                           reinterpret_cast<const CharType*>(that.m_Ptr),
+    int result = FXSYS_cmp(reinterpret_cast<const CharType*>(m_Ptr.Get()),
+                           reinterpret_cast<const CharType*>(that.m_Ptr.Get()),
                            std::min(m_Length, that.m_Length));
     return result < 0 || (result == 0 && m_Length < that.m_Length);
   }
 
  protected:
-  const UnsignedType* m_Ptr;
+  CFX_UnownedPtr<const UnsignedType> m_Ptr;
   FX_STRSIZE m_Length;
 
  private:
diff --git a/core/fxcrt/cfx_unowned_ptr.h b/core/fxcrt/cfx_unowned_ptr.h
index bc58144335..d91833abd4 100644
--- a/core/fxcrt/cfx_unowned_ptr.h
+++ b/core/fxcrt/cfx_unowned_ptr.h
@@ -64,7 +64,7 @@ class CFX_UnownedPtr {
 #if defined(MEMORY_TOOL_REPLACES_ALLOCATOR)
   void Probe() {
     if (m_pObj)
-      reinterpret_cast<volatile uint8_t*>(m_pObj)[0];
+      reinterpret_cast<const volatile uint8_t*>(m_pObj)[0];
   }
 #endif