Add HidlMemory

HidlMemory is a wrapper class to support sp<> for hidl_memory. It
also provides a factory method to create an instance of the 'ashmem'
hidl_memory from a opened file descriptor. The number of factory
methods can be increase to support other type of hidl_memory without
break the ABI.

Change-Id: I18176aecdde1c5c1e10582a4a2e87fe466730e17
Bug: 67758915
Test: with the master branch on the Pixel phone.

1 files changed, 27 insertions, 0 deletions

diff --git a/base/HidlSupport.cpp b/base/HidlSupport.cpp
index 4de7f7c..f857281 100644
--- a/base/HidlSupport.cpp
+++ b/base/HidlSupport.cpp
@@ -273,6 +273,33 @@ bool hidl_string::empty() const {
     return mSize == 0;
 }
 
+sp<HidlMemory> HidlMemory::getInstance(hidl_memory&& mem) {
+    sp<HidlMemory> instance = new HidlMemory();
+    *instance = std::move(mem);
+    return instance;
+}
+
+sp<HidlMemory> HidlMemory::getInstance(const hidl_string& name, int fd, uint64_t size) {
+    native_handle_t* handle = native_handle_create(1, 0);
+    if (!handle) {
+        close(fd);
+        LOG(ERROR) << "native_handle_create fails";
+        return new HidlMemory();
+    }
+    handle->data[0] = fd;
+
+    hidl_handle hidlHandle;
+    hidlHandle.setTo(handle, true /* shouldOwn */);
+
+    sp<HidlMemory> instance = new HidlMemory(name, std::move(hidlHandle), size);
+    return instance;
+}
+
+// it's required to have at least one out-of-line method to avoid weak vtable
+HidlMemory::~HidlMemory() {
+    hidl_memory::~hidl_memory();
+}
+
 }  // namespace hardware
 }  // namespace android