Add input HAL methods for getting device properties.

A property map holds the collection of the properties for a given
device identifier. HAL modules allocate and release these property maps
to control the lifetime of the data. The host will typically open and
read the corresponding idc file on allocation, and release these
resources when it is freed.

Change-Id: Ia13ec7b7abf1a79eeed87dc744c174a37f1fb8a9

1 files changed, 42 insertions, 0 deletions

diff --git a/include/hardware/input.h b/include/hardware/input.h
index 5aa3e51..969b8ce 100644
--- a/include/hardware/input.h
+++ b/include/hardware/input.h
@@ -48,6 +48,10 @@ typedef struct input_report input_report_t;
 
 typedef struct input_collection input_collection_t;
 
+typedef struct input_property_map input_property_map_t;
+
+typedef struct input_property input_property_t;
+
 typedef enum {
     // keycodes
     INPUT_USAGE_KEYCODE_UNKNOWN,
@@ -472,6 +476,44 @@ typedef struct input_host_callbacks {
             input_collection_id_t id, input_usage_t usage, bool value, int32_t arity_index);
 
     void (*report_event)(input_host_t* host, input_device_handle_t* d, input_report_t* report);
+
+    /**
+     * Retrieve the set of properties for the device. The returned
+     * input_property_map_t* may be used to query specific properties via the
+     * input_get_device_property callback.
+     */
+    input_property_map_t* (*input_get_device_property_map)(input_host_t* host,
+            input_device_identifier_t* id);
+    /**
+     * Retrieve a property for the device with the given key. Returns NULL if
+     * the key does not exist, or an input_property_t* that must be freed using
+     * input_free_device_property(). Using an input_property_t after the
+     * corresponding input_property_map_t is freed is undefined.
+     */
+    input_property_t* (*input_get_device_property)(input_host_t* host,
+            input_property_map_t* map, const char* key);
+
+    /**
+     * Get the key for the input property. Returns NULL if the property is NULL.
+     * The returned const char* is owned by the input_property_t.
+     */
+    const char* (*input_get_property_key)(input_host_t* host, input_property_t* property);
+
+    /**
+     * Get the value for the input property. Returns NULL if the property is
+     * NULL. The returned const char* is owned by the input_property_t.
+     */
+    const char* (*input_get_property_value)(input_host_t* host, input_property_t* property);
+
+    /**
+     * Frees the input_property_t*.
+     */
+    void (*input_free_device_property)(input_host_t* host, input_property_t* property);
+
+    /**
+     * Frees the input_property_map_t*.
+     */
+    void (*input_free_device_property_map)(input_host_t* host, input_property_map_t* map);
 } input_host_callbacks_t;
 
 typedef struct input_module input_module_t;