Modify the PPAPI CDM interface to pass more info.

ppapi/api/private/pp_content_decryptor.idl

+/* Copyright (c) 2012 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/**
+ * The <code>PP_DecryptTrackingInfo</code> struct contains necessary information
+ * that can be used to associate the decrypted block with a decrypt request
+ * and/or an input block.
+ */
+[assert_size(16)]
+struct PP_DecryptTrackingInfo {
+  /**
+   * Client-specified identifier for the associated decrypt request. By using
+   * this value, the client can associate the decrypted block with a decryption
+   * request.
+   */
+  uint64_t request_id;
+
+  /**
+   * Timestamp in microseconds of the associated block. By using this value,
+   * the client can associate the decrypted (and decoded) data with an input
+   * block. This is needed because buffers may be delivered out of order and
+   * not in response to the <code>request_id</code> they were provided with.
+   */
+  int64_t timestamp;
+};
+
+/**
+ * The <code>PP_DecryptSubsampleDescription</code> struct contains information
+ * to support subsample decryption.
+ *
+ * An input block can be split into several continuous subsamples.
+ * A <code>PP_DecryptSubsampleEntry</code> specifies the number of clear and
+ * cipher bytes in each subsample. For example, the following block has three
+ * subsamples:
+ *
+ * |<----- subsample1 ----->|<----- subsample2 ----->|<----- subsample3 ----->|
+ * |   clear1   |  cipher1  |  clear2  |   cipher2   | clear3 |    cipher3    |
+ *
+ * For decryption, all of the cipher bytes in a block should be treated as a
+ * contiguous (in the subsample order) logical stream. The clear bytes should
+ * not be considered as part of decryption.
+ *
+ * Logical stream to decrypt:   |  cipher1  |   cipher2   |    cipher3    |
+ * Decrypted stream:            | decrypted1|  decrypted2 |   decrypted3  |
+ *
+ * After decryption, the decrypted bytes should be copied over the position
+ * of the corresponding cipher bytes in the original block to form the output
+ * block. Following the above example, the decrypted block should be:
+ *
+ * |<----- subsample1 ----->|<----- subsample2 ----->|<----- subsample3 ----->|
+ * |   clear1   | decrypted1|  clear2  |  decrypted2 | clear3 |   decrypted3  |
+ */
+[assert_size(8)]
+struct PP_DecryptSubsampleDescription {
+  /**
+   * Size in bytes of clear data in a subsample entry.
+   */
+  uint32_t clear_bytes;
+
+  /**
+   * Size in bytes of encrypted data in a subsample entry.
+   */
+  uint32_t cipher_bytes;
+};
+
+/**
+ * The <code>PP_EncryptedBlockInfo</code> struct contains all the information
+ * needed to decrypt an encrypted block.
+ */
+[assert_size(256)]
+struct PP_EncryptedBlockInfo {
+  /**
+   * Information needed by the client to track the block to be decrypted.
+   */
+  PP_DecryptTrackingInfo tracking_info;
+
+  /**
+   * Size in bytes of data to be discarded before applying the decryption.
+   */
+  uint32_t data_offset;
+
+  /**
+   * Key ID of the block to be decrypted.
+   *
+   * TODO(xhwang): For WebM the key ID can be as large as 2048 bytes in theory.
+   * But it's not used in current implementations. If we really need to support
+   * it, we should move key ID out as a separate parameter, e.g.
+   * as a <code>PP_Var</code>, or make the whole
+   * <code>PP_EncryptedBlockInfo</code> as a <code>PP_Resource</code>.
+   */
+  uint8_t[64] key_id;
+  uint32_t key_id_size;
+
+  /**
+   * Initialization vector of the block to be decrypted.
+   */
+  uint8_t[16] iv;
+  uint32_t iv_size;
+
+  /**
+   * Checksum of the block to be decrypted.
+   */
+  uint8_t[12] checksum;
+  uint32_t checksum_size;
+
+  /**
+   * Subsample information of the block to be decrypted.
+   */
+  PP_DecryptSubsampleDescription[16] subsamples;
+  uint32_t num_subsamples;
+};
+
+/**
+ * The <code>PP_DecryptResult</code> enum contains decryption and decoding
+ * result constants.
+ */
+[assert_size(4)]
+enum PP_DecryptResult {
+  /** The decryption (and/or decoding) operation finished successfully. */
+  PP_DECRYPTRESULT_SUCCESS = 0,
+  /** The decryptor did not have the necessary decryption key. */
+  PP_DECRYPTRESULT_DECRYPT_NOKEY = 1,
+  /** An unexpected error happened during decryption. */
+  PP_DECRYPTRESULT_DECRYPT_ERROR = 2,
+  /** An unexpected error happened during decoding. */
+  PP_DECRYPTRESULT_DECODE_ERROR = 3
+};
+
+/**
+ * The <code>PP_DecryptedBlockInfo</code> struct contains the tracking info and
+ * the decryption (and/or decoding) result associated with the decrypted block.
+ */
+[assert_size(24)]
+struct PP_DecryptedBlockInfo {
+  /**
+   * Information needed by the client to track the block to be decrypted.
+   */
+  PP_DecryptTrackingInfo tracking_info;
+
+  /**
+   * Result of the decryption (and/or decoding) operation.
+   */
+  PP_DecryptResult result;
+
+  /**
+   * 4-byte padding to make the size of <code>PP_DecryptedBlockInfo</code>
+   * a multiple of 8 bytes. The value of this field should not be used.
+   */
+  uint32_t padding;
+};