Port StringPrintf from //base (#624)

* Port StringPrintf from //base.

  Prefer this to approaches based on variadic templates. While the variadic
  template mechanisms are strictly safer, they result in binary bloat we
  can't afford.

  This is essentially the same StringPrintf previously open sourced as a
  part of protobuf, though updated for C++11 which saves a copy and a
  temporary buffer on the heap.

* Add abseil as a subdirectory of Firestore

  This saves having to redefine all the libraries that abseil defines as
  imported libraries.

* Rename firebase_firesture_util_log_* targets

  Cut the log out of the name to reflect that these will get more
  components besides just logging.

2 files changed, 85 insertions, 6 deletions

diff --git a/Firestore/core/test/firebase/firestore/util/CMakeLists.txt b/Firestore/core/test/firebase/firestore/util/CMakeLists.txt
index 42c4dcc..5e10715 100644
--- a/Firestore/core/test/firebase/firestore/util/CMakeLists.txt
+++ b/Firestore/core/test/firebase/firestore/util/CMakeLists.txt
@@ -16,6 +16,7 @@ cc_test(
   firebase_firestore_util_test
   autoid_test.cc
   secure_random_test.cc
+  string_printf_test.cc
 )
 target_link_libraries(
   firebase_firestore_util_test
@@ -24,20 +25,20 @@ target_link_libraries(
 
 if(APPLE)
   cc_test(
-    firebase_firestore_util_log_apple_test
+    firebase_firestore_util_apple_test
     log_test.cc
   )
   target_link_libraries(
-    firebase_firestore_util_log_apple_test
-    firebase_firestore_util_log_apple
+    firebase_firestore_util_apple_test
+    firebase_firestore_util_apple
   )
 endif(APPLE)
 
 cc_test(
-  firebase_firestore_util_log_stdio_test
+  firebase_firestore_util_stdio_test
   log_test.cc
 )
 target_link_libraries(
-  firebase_firestore_util_log_stdio_test
-  firebase_firestore_util_log_stdio
+  firebase_firestore_util_stdio_test
+  firebase_firestore_util_stdio
 )
diff --git a/Firestore/core/test/firebase/firestore/util/string_printf_test.cc b/Firestore/core/test/firebase/firestore/util/string_printf_test.cc
new file mode 100644
index 0000000..76f7cde
--- /dev/null
+++ b/Firestore/core/test/firebase/firestore/util/string_printf_test.cc
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2017 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "Firestore/core/src/firebase/firestore/util/string_printf.h"
+
+#include <gtest/gtest.h>
+
+namespace firebase {
+namespace firestore {
+namespace util {
+
+TEST(StringPrintf, Empty) {
+  EXPECT_EQ("", StringPrintf(""));
+  EXPECT_EQ("", StringPrintf("%s", std::string().c_str()));
+  EXPECT_EQ("", StringPrintf("%s", ""));
+}
+
+TEST(StringAppendFTest, Empty) {
+  std::string value("Hello");
+  const char* empty = "";
+  StringAppendF(&value, "%s", empty);
+  EXPECT_EQ("Hello", value);
+}
+
+TEST(StringAppendFTest, EmptyString) {
+  std::string value("Hello");
+  StringAppendF(&value, "%s", "");
+  EXPECT_EQ("Hello", value);
+}
+
+TEST(StringAppendFTest, String) {
+  std::string value("Hello");
+  StringAppendF(&value, " %s", "World");
+  EXPECT_EQ("Hello World", value);
+}
+
+TEST(StringAppendFTest, Int) {
+  std::string value("Hello");
+  StringAppendF(&value, " %d", 123);
+  EXPECT_EQ("Hello 123", value);
+}
+
+TEST(StringPrintf, DontOverwriteErrno) {
+  // Check that errno isn't overwritten unless we're printing
+  // something significantly larger than what people are normally
+  // printing in their badly written PLOG() statements.
+  errno = ECHILD;
+  std::string value = StringPrintf("Hello, %s!", "World");
+  EXPECT_EQ(ECHILD, errno);
+}
+
+TEST(StringPrintf, LargeBuf) {
+  // Check that the large buffer is handled correctly.
+  int n = 2048;
+  char* buf = new char[n + 1];
+  memset(buf, ' ', n);
+  buf[n] = 0;
+  std::string value = StringPrintf("%s", buf);
+  EXPECT_EQ(buf, value);
+  delete[] buf;
+}
+
+}  //  namespace util
+}  //  namespace firestore
+}  //  namespace firebase