Use NullGuard for signed and unsigned char pointer types, and extend volatile…

Use NullGuard for signed and unsigned char pointer types, and extend volatile pointer type testcase to char pointers.

PiperOrigin-RevId: 501781539
Change-Id: I99012cecd960745de8a921b96671cde42e28a3af

absl/log/internal/nullguard.h

@@ -24,6 +24,7 @@
 #ifndef ABSL_LOG_INTERNAL_NULLGUARD_H_
 #define ABSL_LOG_INTERNAL_NULLGUARD_H_
 
+#include <array>
 #include <cstddef>
 
 #include "absl/base/config.h"
@@ -44,6 +45,34 @@ template <>
 struct NullGuard<const char*> final {
   static const char* Guard(const char* v) { return v ? v : "(null)"; }
 };
+constexpr std::array<signed char, 7> kSignedCharNull{
+    {'(', 'n', 'u', 'l', 'l', ')', '\0'}};
+template <>
+struct NullGuard<signed char*> final {
+  static const signed char* Guard(const signed char* v) {
+    return v ? v : kSignedCharNull.data();
+  }
+};
+template <>
+struct NullGuard<const signed char*> final {
+  static const signed char* Guard(const signed char* v) {
+    return v ? v : kSignedCharNull.data();
+  }
+};
+constexpr std::array<unsigned char, 7> kUnsignedCharNull{
+    {'(', 'n', 'u', 'l', 'l', ')', '\0'}};
+template <>
+struct NullGuard<unsigned char*> final {
+  static const unsigned char* Guard(const unsigned char* v) {
+    return v ? v : kUnsignedCharNull.data();
+  }
+};
+template <>
+struct NullGuard<const unsigned char*> final {
+  static const unsigned char* Guard(const unsigned char* v) {
+    return v ? v : kUnsignedCharNull.data();
+  }
+};
 template <>
 struct NullGuard<std::nullptr_t> final {
   static const char* Guard(const std::nullptr_t&) { return "(null)"; }

absl/log/log_format_test.cc

@@ -665,11 +665,15 @@ TYPED_TEST(VoidPtrLogFormatTest, NonNull) {
 }
 
 template <typename T>
-class VolatileVoidPtrLogFormatTest : public testing::Test {};
-using VolatileVoidPtrTypes = Types<volatile void *, const volatile void *>;
-TYPED_TEST_SUITE(VolatileVoidPtrLogFormatTest, VolatileVoidPtrTypes);
+class VolatilePtrLogFormatTest : public testing::Test {};
+using VolatilePtrTypes =
+    Types<volatile void*, const volatile void*, volatile char*,
+          const volatile char*, volatile signed char*,
+          const volatile signed char*, volatile unsigned char*,
+          const volatile unsigned char*>;
+TYPED_TEST_SUITE(VolatilePtrLogFormatTest, VolatilePtrTypes);
 
-TYPED_TEST(VolatileVoidPtrLogFormatTest, Null) {
+TYPED_TEST(VolatilePtrLogFormatTest, Null) {
   absl::ScopedMockLog test_sink(absl::MockLogDefault::kDisallowUnexpected);
 
   const TypeParam value = nullptr;
@@ -687,7 +691,7 @@ TYPED_TEST(VolatileVoidPtrLogFormatTest, Null) {
   LOG(INFO) << value;
 }
 
-TYPED_TEST(VolatileVoidPtrLogFormatTest, NonNull) {
+TYPED_TEST(VolatilePtrLogFormatTest, NonNull) {
   absl::ScopedMockLog test_sink(absl::MockLogDefault::kDisallowUnexpected);
 
   const TypeParam value = reinterpret_cast<TypeParam>(0xdeadbeefLL);
@@ -707,7 +711,8 @@ TYPED_TEST(VolatileVoidPtrLogFormatTest, NonNull) {
 
 template <typename T>
 class CharPtrLogFormatTest : public testing::Test {};
-using CharPtrTypes = Types<char *, const char *>;
+using CharPtrTypes = Types<char, const char, signed char, const signed char,
+                           unsigned char, const unsigned char>;
 TYPED_TEST_SUITE(CharPtrLogFormatTest, CharPtrTypes);
 
 TYPED_TEST(CharPtrLogFormatTest, Null) {
@@ -717,7 +722,7 @@ TYPED_TEST(CharPtrLogFormatTest, Null) {
   // standard library implementations choose to crash.  We take measures to log
   // something useful instead of crashing, even when that differs from the
   // standard library in use (and thus the behavior of `std::ostream`).
-  const TypeParam value = nullptr;
+  TypeParam* const value = nullptr;
 
   EXPECT_CALL(
       test_sink,
@@ -733,8 +738,8 @@ TYPED_TEST(CharPtrLogFormatTest, Null) {
 TYPED_TEST(CharPtrLogFormatTest, NonNull) {
   absl::ScopedMockLog test_sink(absl::MockLogDefault::kDisallowUnexpected);
 
-  char data[] = "value";
-  const TypeParam value = data;
+  TypeParam data[] = {'v', 'a', 'l', 'u', 'e', '\0'};
+  TypeParam* const value = data;
   auto comparison_stream = ComparisonStream();
   comparison_stream << value;