Flutter SDK 1.0.0发布版

/* * Copyright (c) 2012, 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_API_H_ #define RUNTIME_INCLUDE_DART_API_H_ /** \mainpage Dart Embedding API Reference * * This reference describes the Dart Embedding API, which is used to embed the * Dart Virtual Machine within C/C++ applications. * * This reference is generated from the header include/dart_api.h. */ #ifdef __cplusplus #define DART_EXTERN_C extern "C" #else #define DART_EXTERN_C #endif #if defined(__CYGWIN__) #error Tool chain and platform not supported. #elif defined(_WIN32) // Define bool if necessary. #ifndef __cplusplus typedef unsigned __int8 bool; #endif // Define integer types. typedef signed __int8 int8_t; typedef signed __int16 int16_t; typedef signed __int32 int32_t; typedef signed __int64 int64_t; typedef unsigned __int8 uint8_t; typedef unsigned __int16 uint16_t; typedef unsigned __int32 uint32_t; typedef unsigned __int64 uint64_t; #if defined(DART_SHARED_LIB) #define DART_EXPORT DART_EXTERN_C __declspec(dllexport) #else #define DART_EXPORT DART_EXTERN_C #endif #else /* __STDC_FORMAT_MACROS has to be defined before including <inttypes.h> to * enable platform independent printf format specifiers. */ #ifndef __STDC_FORMAT_MACROS #define __STDC_FORMAT_MACROS #endif #include <inttypes.h> #include <stdbool.h> #if __GNUC__ >= 4 #if defined(DART_SHARED_LIB) #define DART_EXPORT \ DART_EXTERN_C __attribute__((visibility("default"))) __attribute((used)) #else #define DART_EXPORT DART_EXTERN_C #endif #else #error Tool chain not supported. #endif #endif #if __GNUC__ #define DART_WARN_UNUSED_RESULT __attribute__((warn_unused_result)) #elif _MSC_VER #define DART_WARN_UNUSED_RESULT _Check_return_ #else #define DART_WARN_UNUSED_RESULT #endif #include <assert.h> /* * ======= * Handles * ======= */ /** * An isolate is the unit of concurrency in Dart. Each isolate has * its own memory and thread of control. No state is shared between * isolates. Instead, isolates communicate by message passing. * * Each thread keeps track of its current isolate, which is the * isolate which is ready to execute on the current thread. The * current isolate may be NULL, in which case no isolate is ready to * execute. Most of the Dart apis require there to be a current * isolate in order to function without error. The current isolate is * set by any call to Dart_CreateIsolate or Dart_EnterIsolate. */ typedef struct _Dart_Isolate* Dart_Isolate; /** * An object reference managed by the Dart VM garbage collector. * * Because the garbage collector may move objects, it is unsafe to * refer to objects directly. Instead, we refer to objects through * handles, which are known to the garbage collector and updated * automatically when the object is moved. Handles should be passed * by value (except in cases like out-parameters) and should never be * allocated on the heap. * * Most functions in the Dart Embedding API return a handle. When a * function completes normally, this will be a valid handle to an * object in the Dart VM heap. This handle may represent the result of * the operation or it may be a special valid handle used merely to * indicate successful completion. Note that a valid handle may in * some cases refer to the null object. * * --- Error handles --- * * When a function encounters a problem that prevents it from * completing normally, it returns an error handle (See Dart_IsError). * An error handle has an associated error message that gives more * details about the problem (See Dart_GetError). * * There are four kinds of error handles that can be produced, * depending on what goes wrong: * * - Api error handles are produced when an api function is misused. * This happens when a Dart embedding api function is called with * invalid arguments or in an invalid context. * * - Unhandled exception error handles are produced when, during the * execution of Dart code, an exception is thrown but not caught. * Prototypically this would occur during a call to Dart_Invoke, but * it can occur in any function which triggers the execution of Dart * code (for example, Dart_ToString). * * An unhandled exception error provides access to an exception and * stacktrace via the functions Dart_ErrorGetException and * Dart_ErrorGetStackTrace. * * - Compilation error handles are produced when, during the execution * of Dart code, a compile-time error occurs. As above, this can * occur in any function which triggers the execution of Dart code. * * - Fatal error handles are produced when the system wants to shut * down the current isolate. * * --- Propagating errors --- * * When an error handle is returned from the top level invocation of * Dart code in a program, the embedder must handle the error as they * see fit. Often, the embedder will print the error message produced * by Dart_Error and exit the program. * * When an error is returned while in the body of a native function, * it can be propagated up the call stack by calling * Dart_PropagateError, Dart_SetReturnValue, or Dart_ThrowException. * Errors should be propagated unless there is a specific reason not * to. If an error is not propagated then it is ignored. For * example, if an unhandled exception error is ignored, that * effectively "catches" the unhandled exception. Fatal errors must * always be propagated. * * When an error is propagated, any current scopes created by * Dart_EnterScope will be exited. * * Using Dart_SetReturnValue to propagate an exception is somewhat * more convenient than using Dart_PropagateError, and should be * preferred for reasons discussed below. * * Dart_PropagateError and Dart_ThrowException do not return. Instead * they transfer control non-locally using a setjmp-like mechanism. * This can be inconvenient if you have resources that you need to * clean up before propagating the error. * * When relying on Dart_PropagateError, we often return error handles * rather than propagating them from helper functions. Consider the * following contrived example: * * 1 Dart_Handle isLongStringHelper(Dart_Handle arg) { * 2 intptr_t* length = 0; * 3 result = Dart_StringLength(arg, &length); * 4 if (Dart_IsError(result)) { * 5 return result * 6 } * 7 return Dart_NewBoolean(length > 100); * 8 } * 9 * 10 void NativeFunction_isLongString(Dart_NativeArguments args) { * 11 Dart_EnterScope(); * 12 AllocateMyResource(); * 13 Dart_Handle arg = Dart_GetNativeArgument(args, 0); * 14 Dart_Handle result = isLongStringHelper(arg); * 15 if (Dart_IsError(result)) { * 16 FreeMyResource(); * 17 Dart_PropagateError(result); * 18 abort(); // will not reach here * 19 } * 20 Dart_SetReturnValue(result); * 21 FreeMyResource(); * 22 Dart_ExitScope(); * 23 } * * In this example, we have a native function which calls a helper * function to do its work. On line 5, the helper function could call * Dart_PropagateError, but that would not give the native function a * chance to call FreeMyResource(), causing a leak. Instead, the * helper function returns the error handle to the caller, giving the * caller a chance to clean up before propagating the error handle. * * When an error is propagated by calling Dart_SetReturnValue, the * native function will be allowed to complete normally and then the * exception will be propagated only once the native call * returns. This can be convenient, as it allows the C code to clean * up normally. * * The example can be written more simply using Dart_SetReturnValue to * propagate the error. * * 1 Dart_Handle isLongStringHelper(Dart_Handle arg) {