MediaCas: add plugin APIs

bug: 22804304
Change-Id: I87913f39a95278d0d5eb282f2b83b1fa4d362cec
diff --git a/include/media/cas/DescramblerAPI.h b/include/media/cas/DescramblerAPI.h
new file mode 100644
index 0000000..0a51952
--- /dev/null
+++ b/include/media/cas/DescramblerAPI.h
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#ifndef DESCRAMBLER_API_H_
+#define DESCRAMBLER_API_H_
+
+#include <media/stagefright/MediaErrors.h>
+#include <media/cas/CasAPI.h>
+
+namespace android {
+
+struct AString;
+struct DescramblerPlugin;
+
+struct DescramblerFactory {
+    DescramblerFactory() {}
+    virtual ~DescramblerFactory() {}
+
+    // Determine if the plugin can handle the CA scheme identified by CA_system_id.
+    virtual bool isSystemIdSupported(
+            int32_t CA_system_id) const = 0;
+
+    // Construct a new instance of a DescramblerPlugin given a CA_system_id
+    virtual status_t createPlugin(
+            int32_t CA_system_id, DescramblerPlugin **plugin) = 0;
+
+private:
+    DescramblerFactory(const DescramblerFactory &);
+    DescramblerFactory &operator=(const DescramblerFactory &);
+};
+
+struct DescramblerPlugin {
+    enum ScramblingControl {
+        kScrambling_Unscrambled = 0,
+        kScrambling_Reserved    = 1,
+        kScrambling_EvenKey     = 2,
+        kScrambling_OddKey      = 3,
+    };
+
+    struct SubSample {
+        uint32_t mNumBytesOfClearData;
+        uint32_t mNumBytesOfEncryptedData;
+    };
+
+    DescramblerPlugin() {}
+    virtual ~DescramblerPlugin() {}
+
+    // If this method returns false, a non-secure decoder will be used to
+    // decode the data after decryption. The decrypt API below will have
+    // to support insecure decryption of the data (secure = false) for
+    // media data of the given mime type.
+    virtual bool requiresSecureDecoderComponent(const char *mime) const = 0;
+
+    // A MediaCas session may be associated with a MediaCrypto session.  The
+    // associated MediaCas session is used to load decryption keys
+    // into the crypto/cas plugin.  The keys are then referenced by key-id
+    // in the 'key' parameter to the decrypt() method.
+    // Should return NO_ERROR on success, ERROR_DRM_SESSION_NOT_OPENED if
+    // the session is not opened and a code from MediaErrors.h otherwise.
+    virtual status_t setMediaCasSession(const CasSessionId& sessionId) = 0;
+
+    // If the error returned falls into the range
+    // ERROR_DRM_VENDOR_MIN..ERROR_DRM_VENDOR_MAX, errorDetailMsg should be
+    // filled in with an appropriate string.
+    // At the java level these special errors will then trigger a
+    // MediaCodec.CryptoException that gives clients access to both
+    // the error code and the errorDetailMsg.
+    // Returns a non-negative result to indicate the number of bytes written
+    // to the dstPtr, or a negative result to indicate an error.
+    virtual ssize_t descramble(
+            bool secure,
+            ScramblingControl scramblingControl,
+            size_t numSubSamples,
+            const SubSample *subSamples,
+            const void *srcPtr,
+            int32_t srcOffset,
+            void *dstPtr,
+            int32_t dstOffset,
+            AString *errorDetailMsg) = 0;
+
+private:
+    DescramblerPlugin(const DescramblerPlugin &);
+    DescramblerPlugin &operator=(const DescramblerPlugin &);
+};
+
+}  // namespace android
+
+extern "C" {
+    extern android::DescramblerFactory *createDescramblerFactory();
+}
+
+#endif  // DESCRAMBLER_API_H_