| // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file | 
 | // for details. All rights reserved. Use of this source code is governed by a | 
 | // BSD-style license that can be found in the LICENSE file. | 
 |  | 
 | #ifndef RUNTIME_INCLUDE_DART_TOOLS_API_H_ | 
 | #define RUNTIME_INCLUDE_DART_TOOLS_API_H_ | 
 |  | 
 | #include "dart_api.h" /* NOLINT */ | 
 |  | 
 | /** \mainpage Dart Tools Embedding API Reference | 
 |  * | 
 |  * This reference describes the Dart embedding API for tools. Tools include | 
 |  * a debugger, service protocol, and timeline. | 
 |  * | 
 |  * NOTE: The APIs described in this file are unstable and subject to change. | 
 |  * | 
 |  * This reference is generated from the header include/dart_tools_api.h. | 
 |  */ | 
 |  | 
 | /* | 
 |  * ======== | 
 |  * Debugger | 
 |  * ======== | 
 |  */ | 
 |  | 
 | /** | 
 |  * ILLEGAL_ISOLATE_ID is a number guaranteed never to be associated with a | 
 |  * valid isolate. | 
 |  */ | 
 | #define ILLEGAL_ISOLATE_ID ILLEGAL_PORT | 
 |  | 
 | /** | 
 |  * ILLEGAL_ISOLATE_GROUP_ID is a number guaranteed never to be associated with a | 
 |  * valid isolate group. | 
 |  */ | 
 | #define ILLEGAL_ISOLATE_GROUP_ID 0 | 
 |  | 
 | /* | 
 |  * ======= | 
 |  * Service | 
 |  * ======= | 
 |  */ | 
 |  | 
 | /** | 
 |  * A service request callback function. | 
 |  * | 
 |  * These callbacks, registered by the embedder, are called when the VM receives | 
 |  * a service request it can't handle and the service request command name | 
 |  * matches one of the embedder registered handlers. | 
 |  * | 
 |  * The return value of the callback indicates whether the response | 
 |  * should be used as a regular result or an error result. | 
 |  * Specifically, if the callback returns true, a regular JSON-RPC | 
 |  * response is built in the following way: | 
 |  * | 
 |  * { | 
 |  *   "jsonrpc": "2.0", | 
 |  *   "result": <json_object>, | 
 |  *   "id": <some sequence id>, | 
 |  * } | 
 |  * | 
 |  * If the callback returns false, a JSON-RPC error is built like this: | 
 |  * | 
 |  * { | 
 |  *   "jsonrpc": "2.0", | 
 |  *   "error": <json_object>, | 
 |  *   "id": <some sequence id>, | 
 |  * } | 
 |  * | 
 |  * \param method The rpc method name. | 
 |  * \param param_keys Service requests can have key-value pair parameters. The | 
 |  *   keys and values are flattened and stored in arrays. | 
 |  * \param param_values The values associated with the keys. | 
 |  * \param num_params The length of the param_keys and param_values arrays. | 
 |  * \param user_data The user_data pointer registered with this handler. | 
 |  * \param result A C string containing a valid JSON object. The returned | 
 |  *   pointer will be freed by the VM by calling free. | 
 |  * | 
 |  * \return True if the result is a regular JSON-RPC response, false if the | 
 |  *   result is a JSON-RPC error. | 
 |  */ | 
 | typedef bool (*Dart_ServiceRequestCallback)(const char* method, | 
 |                                             const char** param_keys, | 
 |                                             const char** param_values, | 
 |                                             intptr_t num_params, | 
 |                                             void* user_data, | 
 |                                             const char** json_object); | 
 |  | 
 | /** | 
 |  * Register a Dart_ServiceRequestCallback to be called to handle | 
 |  * requests for the named rpc on a specific isolate. The callback will | 
 |  * be invoked with the current isolate set to the request target. | 
 |  * | 
 |  * \param method The name of the method that this callback is responsible for. | 
 |  * \param callback The callback to invoke. | 
 |  * \param user_data The user data passed to the callback. | 
 |  * | 
 |  * NOTE: If multiple callbacks with the same name are registered, only | 
 |  * the last callback registered will be remembered. | 
 |  */ | 
 | DART_EXPORT void Dart_RegisterIsolateServiceRequestCallback( | 
 |     const char* method, | 
 |     Dart_ServiceRequestCallback callback, | 
 |     void* user_data); | 
 |  | 
 | /** | 
 |  * Register a Dart_ServiceRequestCallback to be called to handle | 
 |  * requests for the named rpc. The callback will be invoked without a | 
 |  * current isolate. | 
 |  * | 
 |  * \param method The name of the command that this callback is responsible for. | 
 |  * \param callback The callback to invoke. | 
 |  * \param user_data The user data passed to the callback. | 
 |  * | 
 |  * NOTE: If multiple callbacks with the same name are registered, only | 
 |  * the last callback registered will be remembered. | 
 |  */ | 
 | DART_EXPORT void Dart_RegisterRootServiceRequestCallback( | 
 |     const char* method, | 
 |     Dart_ServiceRequestCallback callback, | 
 |     void* user_data); | 
 |  | 
 | /** | 
 |  * Embedder information which can be requested by the VM for internal or | 
 |  * reporting purposes. | 
 |  * | 
 |  * The pointers in this structure are not going to be cached or freed by the VM. | 
 |  */ | 
 |  | 
 | #define DART_EMBEDDER_INFORMATION_CURRENT_VERSION (0x00000001) | 
 |  | 
 | typedef struct { | 
 |   int32_t version; | 
 |   const char* name;     // [optional] The name of the embedder | 
 |   int64_t current_rss;  // [optional] the current RSS of the embedder | 
 |   int64_t max_rss;      // [optional] the maximum RSS of the embedder | 
 | } Dart_EmbedderInformation; | 
 |  | 
 | /** | 
 |  * Callback provided by the embedder that is used by the VM to request | 
 |  * information. | 
 |  * | 
 |  * \return Returns a pointer to a Dart_EmbedderInformation structure. | 
 |  * The embedder keeps the ownership of the structure and any field in it. | 
 |  * The embedder must ensure that the structure will remain valid until the | 
 |  * next invocation of the callback. | 
 |  */ | 
 | typedef void (*Dart_EmbedderInformationCallback)( | 
 |     Dart_EmbedderInformation* info); | 
 |  | 
 | /** | 
 |  * Register a Dart_ServiceRequestCallback to be called to handle | 
 |  * requests for the named rpc. The callback will be invoked without a | 
 |  * current isolate. | 
 |  * | 
 |  * \param method The name of the command that this callback is responsible for. | 
 |  * \param callback The callback to invoke. | 
 |  * \param user_data The user data passed to the callback. | 
 |  * | 
 |  * NOTE: If multiple callbacks are registered, only the last callback registered | 
 |  * will be remembered. | 
 |  */ | 
 | DART_EXPORT void Dart_SetEmbedderInformationCallback( | 
 |     Dart_EmbedderInformationCallback callback); | 
 |  | 
 | /** | 
 |  * Invoke a vm-service method and wait for its result. | 
 |  * | 
 |  * \param request_json The utf8-encoded json-rpc request. | 
 |  * \param request_json_length The length of the json-rpc request. | 
 |  * | 
 |  * \param response_json The returned utf8-encoded json response, must be | 
 |  *   free()ed by caller. | 
 |  * \param response_json_length The length of the returned json response. | 
 |  * \param error An optional error, must be free()ed by caller. | 
 |  * | 
 |  * \return Whether the call was successfully performed. | 
 |  * | 
 |  * NOTE: This method does not need a current isolate and must not have the | 
 |  * vm-isolate being the current isolate. It must be called after | 
 |  * Dart_Initialize() and before Dart_Cleanup(). | 
 |  */ | 
 | DART_EXPORT bool Dart_InvokeVMServiceMethod(uint8_t* request_json, | 
 |                                             intptr_t request_json_length, | 
 |                                             uint8_t** response_json, | 
 |                                             intptr_t* response_json_length, | 
 |                                             char** error); | 
 |  | 
 | /* | 
 |  * ======== | 
 |  * Event Streams | 
 |  * ======== | 
 |  */ | 
 |  | 
 | /** | 
 |  * A callback invoked when the VM service gets a request to listen to | 
 |  * some stream. | 
 |  * | 
 |  * \return Returns true iff the embedder supports the named stream id. | 
 |  */ | 
 | typedef bool (*Dart_ServiceStreamListenCallback)(const char* stream_id); | 
 |  | 
 | /** | 
 |  * A callback invoked when the VM service gets a request to cancel | 
 |  * some stream. | 
 |  */ | 
 | typedef void (*Dart_ServiceStreamCancelCallback)(const char* stream_id); | 
 |  | 
 | /** | 
 |  * Adds VM service stream callbacks. | 
 |  * | 
 |  * \param listen_callback A function pointer to a listen callback function. | 
 |  *   A listen callback function should not be already set when this function | 
 |  *   is called. A NULL value removes the existing listen callback function | 
 |  *   if any. | 
 |  * | 
 |  * \param cancel_callback A function pointer to a cancel callback function. | 
 |  *   A cancel callback function should not be already set when this function | 
 |  *   is called. A NULL value removes the existing cancel callback function | 
 |  *   if any. | 
 |  * | 
 |  * \return Success if the callbacks were added.  Otherwise, returns an | 
 |  *   error handle. | 
 |  */ | 
 | DART_EXPORT char* Dart_SetServiceStreamCallbacks( | 
 |     Dart_ServiceStreamListenCallback listen_callback, | 
 |     Dart_ServiceStreamCancelCallback cancel_callback); | 
 |  | 
 | /** | 
 |  * Sends a data event to clients of the VM Service. | 
 |  * | 
 |  * A data event is used to pass an array of bytes to subscribed VM | 
 |  * Service clients.  For example, in the standalone embedder, this is | 
 |  * function used to provide WriteEvents on the Stdout and Stderr | 
 |  * streams. | 
 |  * | 
 |  * If the embedder passes in a stream id for which no client is | 
 |  * subscribed, then the event is ignored. | 
 |  * | 
 |  * \param stream_id The id of the stream on which to post the event. | 
 |  * | 
 |  * \param event_kind A string identifying what kind of event this is. | 
 |  *   For example, 'WriteEvent'. | 
 |  * | 
 |  * \param bytes A pointer to an array of bytes. | 
 |  * | 
 |  * \param bytes_length The length of the byte array. | 
 |  * | 
 |  * \return NULL if the arguments are well formed.  Otherwise, returns an | 
 |  *   error string. The caller is responsible for freeing the error message. | 
 |  */ | 
 | DART_EXPORT char* Dart_ServiceSendDataEvent(const char* stream_id, | 
 |                                             const char* event_kind, | 
 |                                             const uint8_t* bytes, | 
 |                                             intptr_t bytes_length); | 
 |  | 
 | /* | 
 |  * ======== | 
 |  * Reload support | 
 |  * ======== | 
 |  * | 
 |  * These functions are used to implement reloading in the Dart VM. | 
 |  * This is an experimental feature, so embedders should be prepared | 
 |  * for these functions to change. | 
 |  */ | 
 |  | 
 | /** | 
 |  * A callback which determines whether the file at some url has been | 
 |  * modified since some time.  If the file cannot be found, true should | 
 |  * be returned. | 
 |  */ | 
 | typedef bool (*Dart_FileModifiedCallback)(const char* url, int64_t since); | 
 |  | 
 | DART_EXPORT char* Dart_SetFileModifiedCallback( | 
 |     Dart_FileModifiedCallback file_modified_callback); | 
 |  | 
 | /** | 
 |  * Returns true if isolate is currently reloading. | 
 |  */ | 
 | DART_EXPORT bool Dart_IsReloading(); | 
 |  | 
 | /* | 
 |  * ======== | 
 |  * Timeline | 
 |  * ======== | 
 |  */ | 
 |  | 
 | /** | 
 |  * Enable tracking of specified timeline category. This is operational | 
 |  * only when systrace timeline functionality is turned on. | 
 |  * | 
 |  * \param categories A comma separated list of categories that need to | 
 |  *   be enabled, the categories are | 
 |  *   "all" : All categories | 
 |  *   "API" - Execution of Dart C API functions | 
 |  *   "Compiler" - Execution of Dart JIT compiler | 
 |  *   "CompilerVerbose" - More detailed Execution of Dart JIT compiler | 
 |  *   "Dart" - Execution of Dart code | 
 |  *   "Debugger" - Execution of Dart debugger | 
 |  *   "Embedder" - Execution of Dart embedder code | 
 |  *   "GC" - Execution of Dart Garbage Collector | 
 |  *   "Isolate" - Dart Isolate lifecycle execution | 
 |  *   "VM" - Execution in Dart VM runtime code | 
 |  *   "" - None | 
 |  * | 
 |  *  When "all" is specified all the categories are enabled. | 
 |  *  When a comma separated list of categories is specified, the categories | 
 |  *   that are specified will be enabled and the rest will be disabled. | 
 |  *  When "" is specified all the categories are disabled. | 
 |  *  The category names are case sensitive. | 
 |  *  eg:  Dart_EnableTimelineCategory("all"); | 
 |  *       Dart_EnableTimelineCategory("GC,API,Isolate"); | 
 |  *       Dart_EnableTimelineCategory("GC,Debugger,Dart"); | 
 |  * | 
 |  * \return True if the categories were successfully enabled, False otherwise. | 
 |  */ | 
 | DART_EXPORT bool Dart_SetEnabledTimelineCategory(const char* categories); | 
 |  | 
 | /** | 
 |  * Returns a timestamp in microseconds. This timestamp is suitable for | 
 |  * passing into the timeline system, and uses the same monotonic clock | 
 |  * as dart:developer's Timeline.now. | 
 |  * | 
 |  * \return A timestamp that can be passed to the timeline system. | 
 |  */ | 
 | DART_EXPORT int64_t Dart_TimelineGetMicros(); | 
 |  | 
 | /** | 
 |  * Returns a raw timestamp in from the monotonic clock. | 
 |  * | 
 |  * \return A raw timestamp from the monotonic clock. | 
 |  */ | 
 | DART_EXPORT int64_t Dart_TimelineGetTicks(); | 
 |  | 
 | /** | 
 |  * Returns the frequency of the monotonic clock. | 
 |  * | 
 |  * \return The frequency of the monotonic clock. | 
 |  */ | 
 | DART_EXPORT int64_t Dart_TimelineGetTicksFrequency(); | 
 |  | 
 | typedef enum { | 
 |   Dart_Timeline_Event_Begin,          // Phase = 'B'. | 
 |   Dart_Timeline_Event_End,            // Phase = 'E'. | 
 |   Dart_Timeline_Event_Instant,        // Phase = 'i'. | 
 |   Dart_Timeline_Event_Duration,       // Phase = 'X'. | 
 |   Dart_Timeline_Event_Async_Begin,    // Phase = 'b'. | 
 |   Dart_Timeline_Event_Async_End,      // Phase = 'e'. | 
 |   Dart_Timeline_Event_Async_Instant,  // Phase = 'n'. | 
 |   Dart_Timeline_Event_Counter,        // Phase = 'C'. | 
 |   Dart_Timeline_Event_Flow_Begin,     // Phase = 's'. | 
 |   Dart_Timeline_Event_Flow_Step,      // Phase = 't'. | 
 |   Dart_Timeline_Event_Flow_End,       // Phase = 'f'. | 
 | } Dart_Timeline_Event_Type; | 
 |  | 
 | /** | 
 |  * Add a timeline event to the embedder stream. | 
 |  * | 
 |  * Note regarding flow events: events must be associated with flow IDs in two | 
 |  * different ways to allow flow events to be serialized correctly in both | 
 |  * Chrome's JSON trace event format and Perfetto's proto trace format. Events | 
 |  * of type |Dart_Timeline_Event_Flow_Begin|, |Dart_Timeline_Event_Flow_Step|, | 
 |  * and |Dart_Timeline_Event_Flow_End| must be reported to support serialization | 
 |  * in Chrome's trace format. The |flow_ids| argument must be supplied when | 
 |  * reporting events of type |Dart_Timeline_Event_Begin|, | 
 |  * |Dart_Timeline_Event_Duration|, |Dart_Timeline_Event_Instant|, | 
 |  * |Dart_Timeline_Event_Async_Begin|, and |Dart_Timeline_Event_Async_Instant| to | 
 |  * support serialization in Perfetto's proto format. | 
 |  * | 
 |  * The Dart VM can use various underlying recorders depending on configuration | 
 |  * and operating system. Many recorders do not support all event types; | 
 |  * unsupported event types are siliently dropped. Some recorders do not accept | 
 |  * timestamps as input, instead implicitly using the time the event is recorded. | 
 |  * For maximum compatibility, record events with the Begin and End types as they | 
 |  * occur instead of using the Duration type or buffering. | 
 |  * | 
 |  * \param label The name of the event. Its lifetime must extend at least until | 
 |  *     Dart_Cleanup. | 
 |  * \param timestamp0 The first timestamp of the event. | 
 |  * \param timestamp1_or_id When reporting an event of type | 
 |  *     |Dart_Timeline_Event_Duration|, the second (end) timestamp of the event | 
 |  *     should be passed through |timestamp1_or_id|. When reporting an event of | 
 |  *     type |Dart_Timeline_Event_Async_Begin|, |Dart_Timeline_Event_Async_End|, | 
 |  *     or |Dart_Timeline_Event_Async_Instant|, the async ID associated with the | 
 |  *     event should be passed through |timestamp1_or_id|. When reporting an | 
 |  *     event of type |Dart_Timeline_Event_Flow_Begin|, | 
 |  *     |Dart_Timeline_Event_Flow_Step|, or |Dart_Timeline_Event_Flow_End|, the | 
 |  *     flow ID associated with the event should be passed through | 
 |  *     |timestamp1_or_id|. When reporting an event of type | 
 |  *     |Dart_Timeline_Event_Begin| or |Dart_Timeline_Event_End|, the event ID | 
 |  *     associated with the event should be passed through |timestamp1_or_id|. | 
 |  *     Note that this event ID will only be used by the MacOS recorder. The | 
 |  *     argument to |timestamp1_or_id| will not be used when reporting events of | 
 |  *     other types. | 
 |  * \param flow_id_count The number of flow IDs associated with this event. | 
 |  * \param flow_ids An array of flow IDs associated with this event. The array | 
 |  *     may be reclaimed when this call returns. | 
 |  * \param argument_count The number of argument names and values. | 
 |  * \param argument_names An array of names of the arguments. The lifetime of the | 
 |  *     names must extend at least until Dart_Cleanup. The array may be reclaimed | 
 |  *     when this call returns. | 
 |  * \param argument_values An array of values of the arguments. The values and | 
 |  *     the array may be reclaimed when this call returns. | 
 |  */ | 
 | DART_EXPORT void Dart_RecordTimelineEvent(const char* label, | 
 |                                           int64_t timestamp0, | 
 |                                           int64_t timestamp1_or_id, | 
 |                                           intptr_t flow_id_count, | 
 |                                           const int64_t* flow_ids, | 
 |                                           Dart_Timeline_Event_Type type, | 
 |                                           intptr_t argument_count, | 
 |                                           const char** argument_names, | 
 |                                           const char** argument_values); | 
 |  | 
 | /** | 
 |  * Associates a name with the current thread. This name will be used to name | 
 |  * threads in the timeline. Can only be called after a call to Dart_Initialize. | 
 |  * | 
 |  * \param name The name of the thread. | 
 |  */ | 
 | DART_EXPORT void Dart_SetThreadName(const char* name); | 
 |  | 
 | typedef struct { | 
 |   const char* name; | 
 |   const char* value; | 
 | } Dart_TimelineRecorderEvent_Argument; | 
 |  | 
 | #define DART_TIMELINE_RECORDER_CURRENT_VERSION (0x00000002) | 
 |  | 
 | typedef struct { | 
 |   /* Set to DART_TIMELINE_RECORDER_CURRENT_VERSION */ | 
 |   int32_t version; | 
 |  | 
 |   /* The event's type / phase. */ | 
 |   Dart_Timeline_Event_Type type; | 
 |  | 
 |   /* The event's timestamp according to the same clock as | 
 |    * Dart_TimelineGetMicros. For a duration event, this is the beginning time. | 
 |    */ | 
 |   int64_t timestamp0; | 
 |  | 
 |   /** | 
 |    * For a duration event, this is the end time. For an async event, this is the | 
 |    * async ID. For a flow event, this is the flow ID. For a begin or end event, | 
 |    * this is the event ID (which is only referenced by the MacOS recorder). | 
 |    */ | 
 |   int64_t timestamp1_or_id; | 
 |  | 
 |   /* The current isolate of the event, as if by Dart_GetMainPortId, or | 
 |    * ILLEGAL_PORT if the event had no current isolate. */ | 
 |   Dart_Port isolate; | 
 |  | 
 |   /* The current isolate group of the event, as if by | 
 |    * Dart_CurrentIsolateGroupId, or ILLEGAL_PORT if the event had no current | 
 |    * isolate group. */ | 
 |   Dart_IsolateGroupId isolate_group; | 
 |  | 
 |   /* The callback data associated with the isolate if any. */ | 
 |   void* isolate_data; | 
 |  | 
 |   /* The callback data associated with the isolate group if any. */ | 
 |   void* isolate_group_data; | 
 |  | 
 |   /* The name / label of the event. */ | 
 |   const char* label; | 
 |  | 
 |   /* The stream / category of the event. */ | 
 |   const char* stream; | 
 |  | 
 |   intptr_t argument_count; | 
 |   Dart_TimelineRecorderEvent_Argument* arguments; | 
 | } Dart_TimelineRecorderEvent; | 
 |  | 
 | /** | 
 |  * Callback provided by the embedder to handle the completion of timeline | 
 |  * events. | 
 |  * | 
 |  * \param event A timeline event that has just been completed. The VM keeps | 
 |  * ownership of the event and any field in it (i.e., the embedder should copy | 
 |  * any values it needs after the callback returns). | 
 |  */ | 
 | typedef void (*Dart_TimelineRecorderCallback)( | 
 |     Dart_TimelineRecorderEvent* event); | 
 |  | 
 | /** | 
 |  * Register a `Dart_TimelineRecorderCallback` to be called as timeline events | 
 |  * are completed. | 
 |  * | 
 |  * The callback will be invoked without a current isolate. | 
 |  * | 
 |  * The callback will be invoked on the thread completing the event. Because | 
 |  * `Dart_RecordTimelineEvent` may be called by any thread, the callback may be | 
 |  * called on any thread. | 
 |  * | 
 |  * The callback may be invoked at any time after `Dart_Initialize` is called and | 
 |  * before `Dart_Cleanup` returns. | 
 |  * | 
 |  * If multiple callbacks are registered, only the last callback registered | 
 |  * will be remembered. Providing a NULL callback will clear the registration | 
 |  * (i.e., a NULL callback produced a no-op instead of a crash). | 
 |  * | 
 |  * Setting a callback is insufficient to receive events through the callback. The | 
 |  * VM flag `timeline_recorder` must also be set to `callback`. | 
 |  */ | 
 | DART_EXPORT void Dart_SetTimelineRecorderCallback( | 
 |     Dart_TimelineRecorderCallback callback); | 
 |  | 
 | /* | 
 |  * ======= | 
 |  * Metrics | 
 |  * ======= | 
 |  */ | 
 |  | 
 | /** | 
 |  * Return metrics gathered for the VM and individual isolates. | 
 |  */ | 
 | DART_EXPORT int64_t | 
 | Dart_IsolateGroupHeapOldUsedMetric(Dart_IsolateGroup group);  // Byte | 
 | DART_EXPORT int64_t | 
 | Dart_IsolateGroupHeapOldCapacityMetric(Dart_IsolateGroup group);  // Byte | 
 | DART_EXPORT int64_t | 
 | Dart_IsolateGroupHeapOldExternalMetric(Dart_IsolateGroup group);  // Byte | 
 | DART_EXPORT int64_t | 
 | Dart_IsolateGroupHeapNewUsedMetric(Dart_IsolateGroup group);  // Byte | 
 | DART_EXPORT int64_t | 
 | Dart_IsolateGroupHeapNewCapacityMetric(Dart_IsolateGroup group);  // Byte | 
 | DART_EXPORT int64_t | 
 | Dart_IsolateGroupHeapNewExternalMetric(Dart_IsolateGroup group);  // Byte | 
 |  | 
 | /* | 
 |  * ======== | 
 |  * UserTags | 
 |  * ======== | 
 |  */ | 
 |  | 
 | /* | 
 |  * Gets the current isolate's currently set UserTag instance. | 
 |  * | 
 |  * \return The currently set UserTag instance. | 
 |  */ | 
 | DART_EXPORT Dart_Handle Dart_GetCurrentUserTag(); | 
 |  | 
 | /* | 
 |  * Gets the current isolate's default UserTag instance. | 
 |  * | 
 |  * \return The default UserTag with label 'Default' | 
 |  */ | 
 | DART_EXPORT Dart_Handle Dart_GetDefaultUserTag(); | 
 |  | 
 | /* | 
 |  * Creates a new UserTag instance. | 
 |  * | 
 |  * \param label The name of the new UserTag. | 
 |  * | 
 |  * \return The newly created UserTag instance or an error handle. | 
 |  */ | 
 | DART_EXPORT Dart_Handle Dart_NewUserTag(const char* label); | 
 |  | 
 | /* | 
 |  * Updates the current isolate's UserTag to a new value. | 
 |  * | 
 |  * \param user_tag The UserTag to be set as the current UserTag. | 
 |  * | 
 |  * \return The previously set UserTag instance or an error handle. | 
 |  */ | 
 | DART_EXPORT Dart_Handle Dart_SetCurrentUserTag(Dart_Handle user_tag); | 
 |  | 
 | /* | 
 |  * Returns the label of a given UserTag instance. | 
 |  * | 
 |  * \param user_tag The UserTag from which the label will be retrieved. | 
 |  * | 
 |  * \return The UserTag's label. NULL if the user_tag is invalid. The caller is | 
 |  *   responsible for freeing the returned label. | 
 |  */ | 
 | DART_EXPORT DART_API_WARN_UNUSED_RESULT char* Dart_GetUserTagLabel( | 
 |     Dart_Handle user_tag); | 
 |  | 
 | /* | 
 |  * ======= | 
 |  * Heap Snapshot | 
 |  * ======= | 
 |  */ | 
 |  | 
 | /** | 
 |  * Callback provided by the caller of `Dart_WriteHeapSnapshot` which is | 
 |  * used to write out chunks of the requested heap snapshot. | 
 |  * | 
 |  * \param context An opaque context which was passed to `Dart_WriteHeapSnapshot` | 
 |  *   together with this callback. | 
 |  * | 
 |  * \param buffer Pointer to the buffer containing a chunk of the snapshot. | 
 |  *   The callback owns the buffer and needs to `free` it. | 
 |  * | 
 |  * \param size Number of bytes in the `buffer` to be written. | 
 |  * | 
 |  * \param is_last Set to `true` for the last chunk. The callback will not | 
 |  *   be invoked again after it was invoked once with `is_last` set to `true`. | 
 |  */ | 
 | typedef void (*Dart_HeapSnapshotWriteChunkCallback)(void* context, | 
 |                                                     uint8_t* buffer, | 
 |                                                     intptr_t size, | 
 |                                                     bool is_last); | 
 |  | 
 | /** | 
 |  * Generate heap snapshot of the current isolate group and stream it into the | 
 |  * given `callback`. VM would produce snapshot in chunks and send these chunks | 
 |  * one by one back to the embedder by invoking the provided `callback`. | 
 |  * | 
 |  * This API enables embedder to stream snapshot into a file or socket without | 
 |  * allocating a buffer to hold the whole snapshot in memory. | 
 |  * | 
 |  * The isolate group will be paused for the duration of this operation. | 
 |  * | 
 |  * \param write Callback used to write chunks of the heap snapshot. | 
 |  * | 
 |  * \param context Opaque context which would be passed on each invocation of | 
 |  *   `write` callback. | 
 |  * | 
 |  * \returns `nullptr` if the operation is successful otherwise error message. | 
 |  *   Caller owns error message string and needs to `free` it. | 
 |  */ | 
 | DART_EXPORT char* Dart_WriteHeapSnapshot( | 
 |     Dart_HeapSnapshotWriteChunkCallback write, | 
 |     void* context); | 
 |  | 
 | #endif  // RUNTIME_INCLUDE_DART_TOOLS_API_H_ |