Add support for sending and receiving ParcelFileDescriptors from native Binder code

Change-Id: I7f308e28ebac0755628e19c9b4d0d7399341b435
diff --git a/libs/binder/Parcel.cpp b/libs/binder/Parcel.cpp
index 7a5919f..d130d7c 100644
--- a/libs/binder/Parcel.cpp
+++ b/libs/binder/Parcel.cpp
@@ -750,6 +750,32 @@
     return err;
 }
 
+// WARNING: This method must stay in sync with
+// Parcelable.Creator<ParcelFileDescriptor> CREATOR
+// in frameworks/base/core/java/android/os/ParcelFileDescriptor.java
+status_t Parcel::writeParcelFileDescriptor(int fd, int commChannel) {
+    status_t status;
+
+    if (fd < 0) {
+        status = writeInt32(0); // ParcelFileDescriptor is null
+        if (status) return status;
+    } else {
+        status = writeInt32(1); // ParcelFileDescriptor is not null
+        if (status) return status;
+        status = writeDupFileDescriptor(fd);
+        if (status) return status;
+        if (commChannel < 0) {
+            status = writeInt32(0); // commChannel is null
+            if (status) return status;
+        } else {
+            status = writeInt32(1); // commChannel is not null
+            if (status) return status;
+            status = writeDupFileDescriptor(commChannel);
+        }
+    }
+    return status;
+}
+
 status_t Parcel::writeBlob(size_t len, WritableBlob* outBlob)
 {
     status_t status;
@@ -1148,6 +1174,23 @@
     return BAD_TYPE;
 }
 
+// WARNING: This method must stay in sync with writeToParcel()
+// in frameworks/base/core/java/android/os/ParcelFileDescriptor.java
+int Parcel::readParcelFileDescriptor(int& outCommChannel) const {
+    int fd;
+    outCommChannel = -1;
+
+    if (readInt32() == 0) {
+        fd = -1;
+    } else {
+        fd = readFileDescriptor();
+        if (fd >= 0 && readInt32() != 0) {
+            outCommChannel = readFileDescriptor();
+        }
+    }
+    return fd;
+}
+
 status_t Parcel::readBlob(size_t len, ReadableBlob* outBlob) const
 {
     int32_t useAshmem;