FIDL 範例：計算機

本計算機範例說明如何使用 建構 FIDL 通訊協定 功能最基本在這個例子中，您將修改 可能傳回錯誤、組合 FIDL 通訊協定與其他程式 並展示其他基元的用法

開始使用

在這個範例中，您將建立基本的計算機伺服器用戶端會顯示用來 如要先定義並提供及使用 FIDL 通訊協定，則須有基本設定。

首先，請定義介面定義並測試控管工具。 介面定義 (.fidl 檔案本身) 是任何新資料的起點 FIDL 通訊協定。此外，計算機還包括必要的 CML 和領域 建立可用於專案的用戶端與伺服器模式的定義 進行任意實作的 Scaffold

以下為 FIDL 代碼：

FIDL

// Copyright 2022 The Fuchsia 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 namespace for this FIDL protocol. This namespace is how both consumers (clients) and providers (servers) reference this protocol.
library examples.calculator.baseline;

// @discoverable indicates 'Calculator' is a protocol that will be served under the examples.calculator.baseline libarary namespace. https://fuchsia.dev/fuchsia-src/reference/fidl/language/attributes#discoverable . If @discoverable is missing, it will lead to a compile time error when trying to import the library.
@discoverable
// A limited-functionality calculator 'protocol' that adds and subtracts integers.
open protocol Calculator {
    // Takes as input a struct with two integers, and returns their sum: (a+b)=sum.  This method is infallible (no errors can be generated) as two int32's cannot overflow a result type of int64.
    flexible Add(struct {
        a int32;
        b int32;
    }) -> (struct {
        sum int64;
    });
    // Takes as input a struct with two integers, and returns their difference: (a-b)=difference.  This method is infallible (no errors can be generated) as two int32's cannot overflow a result type of int64.
    flexible Subtract(struct {
        a int32;
        b int32;
    }) -> (struct {
        difference int64;
    });
};

CML

用戶端

// Copyright 2022 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
{
    include: [ "syslog/client.shard.cml" ],
    program: {
        runner: "elf",
        binary: "bin/client_bin",
    },
    use: [
        { protocol: "examples.calculator.baseline.Calculator" },
    ],
    config: {},
}

伺服器

// Copyright 2022 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
{
    include: [ "syslog/client.shard.cml" ],
    program: {
        runner: "elf",
        binary: "bin/server_bin",
    },
    capabilities: [
        { protocol: "examples.calculator.baseline.Calculator" },
    ],
    expose: [
        {
            protocol: "examples.calculator.baseline.Calculator",
            from: "self",
        },
    ],
}

領域

// Copyright 2022 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
{
    children: [
        {
            name: "client",
            url: "#meta/client.cm",
        },
        {
            name: "server",
            url: "#meta/server.cm",
        },
    ],
    offer: [
        // Route the protocol under test from the server to the client.
        {
            protocol: "examples.calculator.baseline.Calculator",
            from: "#server",
            to: "#client",
        },

        // Route logging support to all children.
        {
            protocol: [
                "fuchsia.inspect.InspectSink",
                "fuchsia.logger.LogSink",
            ],
            from: "parent",
            to: [
                "#client",
                "#server",
            ],
        },
    ],
}

用戶端和伺服器實作項目現在可以使用任何支援的語言編寫：

荒漠油廠

用戶端

// TODO(https://fxbug.dev/42063075): Rust implementation.

伺服器

// TODO(https://fxbug.dev/42063075): Rust implementation.

C++ (自然)

用戶端

// TODO(https://fxbug.dev/42063075): C++ (Natural) implementation.

伺服器

// TODO(https://fxbug.dev/42063075): C++ (Natural) implementation.

C++ (有線)

用戶端

// TODO(https://fxbug.dev/42063075): C++ (Wire) implementation.

伺服器

// TODO(https://fxbug.dev/42063075): C++ (Wire) implementation.

HLCPP

用戶端

// TODO(https://fxbug.dev/42063075): HLCPP implementation.

伺服器

// TODO(https://fxbug.dev/42063075): HLCPP implementation.

如以下範例所示，從頭開始建立 FIDL 通訊協定 更常見的情境，例如平台開發人員 不過，其他類型的開發人員也能藉由瞭解 或 FIDL 通訊協定。這有助於瞭解 所有 FIDL 的相關資訊都整合在一起，包括語法、文法和語言 包括如何提供和使用指定的 FIDL 通訊協定 以及每個 VM 的運作原理如要瞭解後續步驟，請參考這個基準線的範例， 擴充現有的 FIDL 通訊協定，在預期發生類似情況時 練習。

改善設計

以下各節將探索一種可能的疊代方式 原始設計。每個學習路徑都不必依序建構 的論述獨立方式， 遭到修改或改良