hidl_string: allow null cstr

Automatically converting nullptr to empty string rather than erroring.
This gets rid of null values at the hal layer (rather than passing them
to the server) and simplifies code that would have to check for nulls.

Test: libhidl_test
Fixes: 35421240
Change-Id: Iada25da5407c3eccdd28704d993ffdee8b15c5fe

1 files changed, 4 insertions, 0 deletions

diff --git a/base/HidlSupport.cpp b/base/HidlSupport.cpp
index 1544969..68155cd 100644
--- a/base/HidlSupport.cpp
+++ b/base/HidlSupport.cpp
@@ -195,6 +195,10 @@ hidl_string::~hidl_string() {
 }
 
 hidl_string::hidl_string(const char *s) : hidl_string() {
+    if (s == nullptr) {
+        return;
+    }
+
     copyFrom(s, strlen(s));
 }