/*
* Copyright (C) 2011 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 HW_EMULATOR_CAMERA_QEMU_CLIENT_H
#define HW_EMULATOR_CAMERA_QEMU_CLIENT_H
/*
* Contains declaration of classes that encapsulate connection to camera services
* in the emulator via qemu pipe.
*/
#include <hardware/qemud.h>
namespace android {
/****************************************************************************
* Qemu query
***************************************************************************/
/* Encapsulates a query to the emulator.
* Guest exchanges data with the emulator via queries sent over the qemu pipe.
* The queries as well as replies to the queries are all strings (except for the
* 'frame' query where reply is a framebuffer).
* Each query is formatted as such:
*
* "<query name>[ <parameters>]",
*
* where <query name> is a string representing query name, and <parameters> are
* optional parameters for the query. If parameters are present, they must be
* separated from the query name with a single space, and they must be formatted
* as such:
*
* "<name1>=<value1> <name2>=<value2> ... <nameN>=<valueN>"
*
* I.e.:
* - Every parameter must have a name, and a value.
* - Name and value must be separated with '='.
* - No spaces are allowed around '=' separating name and value.
* - Parameters must be separated with a single space character.
* - No '=' character is allowed in name and in value.
*
* There are certain restrictions on strings used in the query:
* - Spaces are allowed only as separators.
* - '=' are allowed only to divide parameter names from parameter values.
*
* Emulator replies to each query in two chunks:
* - 8 bytes encoding the payload size as a string containing hexadecimal
* representation of the payload size value. This is done in order to simplify
* dealing with different endianness on the host, and on the guest.
* - Payload, whose size is defined by the first chunk.
*
* Every payload always begins with two characters, encoding the result of the
* query:
* - 'ok' Encoding the success
* - 'ko' Encoding a failure.
* After that payload may have optional data. If payload has more data following
* the query result, there is a ':' character separating them. If payload carries
* only the result, it always ends with a zero-terminator. So, payload 'ok'/'ko'
* prefix is always 3 bytes long: it either includes a zero-terminator, if there
* is no data, or a ':' separator.
*/
class QemuQuery {
public:
/* Constructs an uninitialized QemuQuery instance. */
QemuQuery();
/* Constructs and initializes QemuQuery instance for a query.
* Param:
* query_string - Query string. This constructor can also be used to
* construct a query that doesn't have parameters. In this case query
* name can be passed as a parameter here.
*/
explicit QemuQuery(const char* query_string);
/* Constructs and initializes QemuQuery instance for a query with parameters.
* Param:
* query_name - Query name.
* query_param - Query parameters. Can be NULL.
*/
QemuQuery(const char* query_name, const char* query_param);
/* Destructs QemuQuery instance. */
~QemuQuery();
/****************************************************************************
* Public API
***************************************************************************/
/* Creates new query.
* Note: this method will reset this instance prior to creating a new query
* in order to discard possible "leftovers" from the previous query.
* Param:
* query_name - Query name.
* query_param - Query parameters. Can be NULL.
* Return:
* NO_ERROR on success, or an appropriate error status.
*/
status_t createQuery(const char* name, const char* param);
/* Completes the query after a reply from the emulator.
* This method will parse the reply buffer, and calculate the final query
* status, which depends not only on the transport success / failure, but
* also on 'ok' / 'ko' in the reply buffer.
* Param:
* status - Query delivery status. This status doesn't necessarily reflects
* the final query status (which is defined by 'ok'/'ko' prefix in the
* reply buffer). This status simply states whether or not the query has
* been sent, and a reply has been received successfuly. However, if
* this status indicates a failure, it means that the entire query has
* failed.
* Return:
* NO_ERROR on success, or an appropriate error status on failure. Note that
* status returned here just signals whether or not the method has succeeded.
* Use isQuerySucceeded() / getCompletionStatus() methods of this class to
* check the final query status.
*/
status_t completeQuery(status_t status);
/* Resets the query from a previous use. */
void resetQuery();
/* Checks if query has succeeded.
* Note that this method must be called after completeQuery() method of this
* class has been executed.
*/
inline bool isQuerySucceeded() const {
return mQueryDeliveryStatus == NO_ERROR && mReplyStatus != 0;
}
/* Gets final completion status of the query.
* Note that this method must be called after completeQuery() method of this
* class has been executed.
* Return:
* NO_ERROR if query has succeeded, or an appropriate error status on query
* failure.
*/
inline status_t getCompletionStatus() const {
if (mQueryDeliveryStatus == NO_ERROR) {
if (mReplyStatus) {
return NO_ERROR;
} else {
return EINVAL;
}
} else {
return mQueryDeliveryStatus;
}
}
/****************************************************************************
* Public data memebers
***************************************************************************/
public:
/* Query string. */
char* mQuery;
/* Query delivery status. */
status_t mQueryDeliveryStatus;
/* Reply buffer */
char* mReplyBuffer;
/* Reply data (past 'ok'/'ko'). If NULL, there were no data in reply. */
char* mReplyData;
/* Reply buffer size. */
size_t mReplySize;
/* Reply data size. */
size_t mReplyDataSize;
/* Reply status: 1 - ok, 0 - ko. */
int mReplyStatus;
/****************************************************************************
* Private data memebers
***************************************************************************/
protected:
/* Preallocated buffer for small queries. */
char mQueryPrealloc[256];
};
/****************************************************************************
* Qemu client base
***************************************************************************/
/* Encapsulates a connection to the 'camera' service in the emulator via qemu
* pipe.
*/
class QemuClient {
public:
/* Constructs QemuClient instance. */
QemuClient();
/* Destructs QemuClient instance. */
virtual ~QemuClient();
/****************************************************************************
* Qemu client API
***************************************************************************/
public:
/* Connects to the 'camera' service in the emulator via qemu pipe.
* Param:
* param - Parameters to pass to the camera service. There are two types of
* camera services implemented by the emulator. The first one is a
* 'camera factory' type of service that provides list of cameras
* connected to the host. Another one is an 'emulated camera' type of
* service that provides interface to a camera connected to the host. At
* the connection time emulator makes distinction between the two by
* looking at connection parameters: no parameters means connection to
* the 'factory' service, while connection with parameters means
* connection to an 'emulated camera' service, where camera is identified
* by one of the connection parameters. So, passing NULL, or an empty
* string to this method will establish a connection with the 'factory'
* service, while not empty string passed here will establish connection
* with an 'emulated camera' service. Parameters defining the emulated
* camera must be formatted as such:
*
* "name=<device name> [inp_channel=<input channel #>]",
*
* where 'device name' is a required parameter defining name of the
* camera device, and 'input channel' is an optional parameter (positive
* integer), defining the input channel to use on the camera device.
* Note that device name passed here must have been previously obtained
* from the factory service using 'list' query.
* Return:
* NO_ERROR on success, or an appropriate error status.
*/
virtual status_t connectClient(const char* param);
/* Disconnects from the service. */
virtual void disconnectClient();
/* Sends data to the service.
* Param:
* data, data_size - Data to send.
* Return:
* NO_ERROR on success, or an appropriate error status on failure.
*/
virtual status_t sendMessage(const void* data, size_t data_size);
/* Receives data from the service.
* This method assumes that data to receive will come in two chunks: 8
* characters encoding the payload size in hexadecimal string, followed by
* the paylod (if any).
* This method will allocate data buffer where to receive the response.
* Param:
* data - Upon success contains address of the allocated data buffer with
* the data received from the service. The caller is responsible for
* freeing allocated data buffer.
* data_size - Upon success contains size of the data received from the
* service.
* Return:
* NO_ERROR on success, or an appropriate error status on failure.
*/
virtual status_t receiveMessage(void** data, size_t* data_size);
/* Sends a query, and receives a response from the service.
* Param:
* query - Query to send to the service. When this method returns, the query
* is completed, and all its relevant data members are properly initialized.
* Return:
* NO_ERROR on success, or an appropriate error status on failure. Note that
* status returned here is not the final query status. Use isQuerySucceeded(),
* or getCompletionStatus() method on the query object to see if it has
* succeeded. However, if this method returns a failure, it means that the
* query has failed, and there is no guarantee that its data members are
* properly initialized (except for the 'mQueryDeliveryStatus', which is
* always in the proper state).
*/
virtual status_t doQuery(QemuQuery* query);
/****************************************************************************
* Data members
***************************************************************************/
protected:
/* Qemu pipe handle. */
int mPipeFD;
private:
/* Camera service name. */
static const char mCameraServiceName[];
};
/****************************************************************************
* Qemu client for the 'factory' service.
***************************************************************************/
/* Encapsulates QemuClient for the 'factory' service. */
class FactoryQemuClient : public QemuClient {
public:
/* Constructs FactoryQemuClient instance. */
FactoryQemuClient();
/* Destructs FactoryQemuClient instance. */
~FactoryQemuClient();
/****************************************************************************
* Public API
***************************************************************************/
public:
/* Lists camera devices connected to the host.
* Param:
* list - Upon success contains a list of cameras connected to the host. The
* list returned here is represented as a string, containing multiple
* lines separated with '\n', where each line represents a camera. Each
* camera line is formatted as such:
*
* "name=<device name> channel=<num> pix=<num> framedims=<dimensions>\n"
*
* Where:
* - 'name' is the name of the camera device attached to the host. This
* name must be used for subsequent connection to the 'emulated camera'
* service for that camera.
* - 'channel' - input channel number (positive int) to use to communicate
* with the camera.
* - 'pix' - pixel format (a "fourcc" uint), chosen for the video frames
* by the camera service.
* - 'framedims' contains a list of frame dimensions supported by the
* camera for the chosen pixel format. Each etry in the list is in form
* '<width>x<height>', where 'width' and 'height' are numeric values
* for width and height of a supported frame dimension. Entries in
* this list are separated with ',' with no spaces between the entries.
* Return:
* NO_ERROR on success, or an appropriate error status on failure.
*/
status_t listCameras(char** list);
/****************************************************************************
* Names of the queries available for the emulated camera factory.
***************************************************************************/
private:
/* List cameras connected to the host. */
static const char mQueryList[];
};
/****************************************************************************
* Qemu client for an 'emulated camera' service.
***************************************************************************/
/* Encapsulates QemuClient for an 'emulated camera' service.
*/
class CameraQemuClient : public QemuClient {
public:
/* Constructs CameraQemuClient instance. */
CameraQemuClient();
/* Destructs CameraQemuClient instance. */
~CameraQemuClient();
/****************************************************************************
* Public API
***************************************************************************/
public:
/* Queries camera connection.
* Return:
* NO_ERROR on success, or an appropriate error status on failure.
*/
status_t queryConnect();
/* Queries camera disconnection.
* Return:
* NO_ERROR on success, or an appropriate error status on failure.
*/
status_t queryDisconnect();
/* Queries camera to start capturing video.
* Param:
* pixel_format - Pixel format that is used by the client to push video
* frames to the camera framework.
* width, height - Frame dimensions, requested by the framework.
* Return:
* NO_ERROR on success, or an appropriate error status on failure.
*/
status_t queryStart(uint32_t pixel_format, int width, int height);
/* Queries camera to stop capturing video.
* Return:
* NO_ERROR on success, or an appropriate error status on failure.
*/
status_t queryStop();
/* Queries camera for the next video frame.
* Param:
* vframe, vframe_size - Define buffer, allocated to receive a video frame.
* Any of these parameters can be 0, indicating that the caller is
* interested only in preview frame.
* pframe, pframe_size - Define buffer, allocated to receive a preview frame.
* Any of these parameters can be 0, indicating that the caller is
* interested only in video frame.
* r_scale, g_scale, b_scale - White balance scale.
* exposure_comp - Expsoure compensation.
* Return:
* NO_ERROR on success, or an appropriate error status on failure.
*/
status_t queryFrame(void* vframe,
void* pframe,
size_t vframe_size,
size_t pframe_size,
float r_scale,
float g_scale,
float b_scale,
float exposure_comp);
/****************************************************************************
* Names of the queries available for the emulated camera.
***************************************************************************/
private:
/* Connect to the camera. */
static const char mQueryConnect[];
/* Disconnect from the camera. */
static const char mQueryDisconnect[];
/* Start video capturing. */
static const char mQueryStart[];
/* Stop video capturing. */
static const char mQueryStop[];
/* Query frame(s). */
static const char mQueryFrame[];
};
}; /* namespace android */
#endif /* HW_EMULATOR_CAMERA_QEMU_CLIENT_H */