commit 34fb6e12224989f8442699ec22d2fcbd5070a346
author Steven Moreland <smoreland@google.com> Mon Mar 29 21:13:37 2021 +0000
committer Gerrit Code Review <noreply-gerritcodereview@google.com> Mon Mar 29 21:13:37 2021 +0000
tree b2ee6796c081cb83f9fd185f82b9386a3dd3f9d1
parent e5f8f7c02c3744378a759143573b1e74f65ad32f
parent e5b0df28eb4179c1971ec143a13146a50a895e58

Merge "hidl_string: empty string opt always applies"

base/HidlSupport.cpp

diff --git a/base/HidlSupport.cpp b/base/HidlSupport.cpp
index af805b9..78faa2f 100644
--- a/base/HidlSupport.cpp
+++ b/base/HidlSupport.cpp
@@ -217,6 +217,14 @@
     if (size >= UINT32_MAX) {
         LOG(FATAL) << "string size can't exceed 2^32 bytes: " << size;
     }
+
+    if (size == 0) {
+        mBuffer = kEmptyString;
+        mSize = 0;
+        mOwnsBuffer = false;
+        return;
+    }
+
     char *buf = (char *)malloc(size + 1);
     memcpy(buf, data, size);
     buf[size] = '\0';

test_main.cpp

diff --git a/test_main.cpp b/test_main.cpp
index ea4dfd1..5c6c78e 100644
--- a/test_main.cpp
+++ b/test_main.cpp
@@ -175,6 +175,20 @@
     EXPECT_FALSE(hs2 <= hs1);
 }
 
+// empty string optimization should apply for any constructor
+TEST_F(LibHidlTest, HidlStringEmptyLiteralAllocation) {
+    using android::hardware::hidl_string;
+
+    hidl_string empty1;
+    hidl_string empty2("");
+    hidl_string empty3("foo", 0);
+    hidl_string empty4((std::string()));
+
+    EXPECT_EQ(empty1.c_str(), empty2.c_str());
+    EXPECT_EQ(empty1.c_str(), empty3.c_str());
+    EXPECT_EQ(empty1.c_str(), empty4.c_str());
+}
+
 TEST_F(LibHidlTest, MemoryTest) {
     using android::hardware::hidl_memory;