Make SimpleStringBuilder into a non-template

So that future CLs can de-inline its methods.

We do this by asking the caller to allocate the buffer instead of
having it as a data member.

Bug: webrtc:8982
Change-Id: I246b0973e54510fdd880c3b6875336c31334d008
Reviewed-on: https://webrtc-review.googlesource.com/60000
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22355}

rtc_base/strings/string_builder_unittest.cc

@@ -11,13 +11,15 @@
 #include "rtc_base/strings/string_builder.h"
 
 #include "rtc_base/checks.h"
-#include "rtc_base/gunit.h"
 #include "rtc_base/stringutils.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
 
 namespace rtc {
 
 TEST(SimpleStringBuilder, Limit) {
-  SimpleStringBuilder<10> sb;
+  char sb_buf[10];
+  SimpleStringBuilder sb(sb_buf);
   EXPECT_EQ(0u, strlen(sb.str()));
 
   // Test that for a SSB with a buffer size of 10, that we can write 9 chars
@@ -27,26 +29,115 @@ TEST(SimpleStringBuilder, Limit) {
 }
 
 TEST(SimpleStringBuilder, NumbersAndChars) {
-  SimpleStringBuilder<100> sb;
+  char sb_buf[100];
+  SimpleStringBuilder sb(sb_buf);
   sb << 1 << ':' << 2.1 << ":" << 2.2f << ':' << 78187493520ll << ':'
      << 78187493520ul;
   EXPECT_EQ(0, strcmp(sb.str(), "1:2.100000:2.200000:78187493520:78187493520"));
 }
 
 TEST(SimpleStringBuilder, Format) {
-  SimpleStringBuilder<100> sb;
+  char sb_buf[100];
+  SimpleStringBuilder sb(sb_buf);
   sb << "Here we go - ";
-  sb.AppendFormat("This is a hex formatted value: 0x%08x", 3735928559);
+  sb.AppendFormat("This is a hex formatted value: 0x%08llx", 3735928559ULL);
   EXPECT_EQ(0,
             strcmp(sb.str(),
                    "Here we go - This is a hex formatted value: 0xdeadbeef"));
 }
 
 TEST(SimpleStringBuilder, StdString) {
-  SimpleStringBuilder<100> sb;
+  char sb_buf[100];
+  SimpleStringBuilder sb(sb_buf);
   std::string str = "does this work?";
   sb << str;
   EXPECT_EQ(str, sb.str());
 }
 
+// These tests are safe to run if we have death test support or if DCHECKs are
+// off.
+#if (GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)) || !RTC_DCHECK_IS_ON
+
+TEST(SimpleStringBuilder, BufferOverrunConstCharP) {
+  char sb_buf[4];
+  SimpleStringBuilder sb(sb_buf);
+  const char* const msg = "This is just too much";
+#if RTC_DCHECK_IS_ON
+  EXPECT_DEATH(sb << msg, "");
+#else
+  sb << msg;
+  EXPECT_THAT(sb.str(), testing::StrEq("Thi"));
+#endif
+}
+
+TEST(SimpleStringBuilder, BufferOverrunStdString) {
+  char sb_buf[4];
+  SimpleStringBuilder sb(sb_buf);
+  sb << 12;
+  const std::string msg = "Aw, come on!";
+#if RTC_DCHECK_IS_ON
+  EXPECT_DEATH(sb << msg, "");
+#else
+  sb << msg;
+  EXPECT_THAT(sb.str(), testing::StrEq("12A"));
+#endif
+}
+
+TEST(SimpleStringBuilder, BufferOverrunInt) {
+  char sb_buf[4];
+  SimpleStringBuilder sb(sb_buf);
+  constexpr int num = -12345;
+#if RTC_DCHECK_IS_ON
+  EXPECT_DEATH(sb << num, "");
+#else
+  sb << num;
+  // If we run into the end of the buffer, resonable results are either that
+  // the append has no effect or that it's truncated at the point where the
+  // buffer ends.
+  EXPECT_THAT(sb.str(),
+              testing::AnyOf(testing::StrEq(""), testing::StrEq("-12")));
+#endif
+}
+
+TEST(SimpleStringBuilder, BufferOverrunDouble) {
+  char sb_buf[5];
+  SimpleStringBuilder sb(sb_buf);
+  constexpr double num = 123.456;
+#if RTC_DCHECK_IS_ON
+  EXPECT_DEATH(sb << num, "");
+#else
+  sb << num;
+  EXPECT_THAT(sb.str(),
+              testing::AnyOf(testing::StrEq(""), testing::StrEq("123.")));
+#endif
+}
+
+TEST(SimpleStringBuilder, BufferOverrunConstCharPAlreadyFull) {
+  char sb_buf[4];
+  SimpleStringBuilder sb(sb_buf);
+  sb << 123;
+  const char* const msg = "This is just too much";
+#if RTC_DCHECK_IS_ON
+  EXPECT_DEATH(sb << msg, "");
+#else
+  sb << msg;
+  EXPECT_THAT(sb.str(), testing::StrEq("123"));
+#endif
+}
+
+TEST(SimpleStringBuilder, BufferOverrunIntAlreadyFull) {
+  char sb_buf[4];
+  SimpleStringBuilder sb(sb_buf);
+  sb << "xyz";
+  constexpr int num = -12345;
+#if RTC_DCHECK_IS_ON
+  EXPECT_DEATH(sb << num, "");
+#else
+  sb << num;
+  EXPECT_THAT(sb.str(), testing::StrEq("xyz"));
+#endif
+}
+
+#endif
+
 }  // namespace rtc