winget-cli

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Settings.h (4110B)

      1 // Copyright (c) Microsoft Corporation.
      2 // Licensed under the MIT License.
      3 #pragma once
      4 #include <filesystem>
      5 #include <memory>
      6 #include <string>
      7 #include <string_view>
      8 
      9 namespace AppInstaller::Settings
     10 {
     11     using namespace std::string_view_literals;
     12 
     13     namespace details
     14     {
     15         // A settings container.
     16         struct ISettingsContainer
     17         {
     18             virtual ~ISettingsContainer() = default;
     19 
     20             // Gets a stream containing the setting's value, if present.
     21             // If the setting does not exist, returns an empty value.
     22             virtual std::unique_ptr<std::istream> Get() = 0;
     23 
     24             // Sets the setting to the given value.
     25             virtual bool Set(std::string_view value) = 0;
     26 
     27             // Deletes the setting.
     28             virtual void Remove() = 0;
     29 
     30             // Gets the path to the setting, if reasonable.
     31             virtual std::filesystem::path PathTo() = 0;
     32         };
     33     }
     34 
     35     // Allows settings to be classified and treated differently base on any number of factors.
     36     // Names should still be unique, as there is no guarantee made about types mapping to unique roots.
     37     enum class Type
     38     {
     39         // A Standard setting stream has no special requirements.
     40         Standard,
     41         // A UserFile setting stream should be located in a file that is easily editable by the user.
     42         UserFile,
     43         // A settings stream that should not be modified except by admin privileges.
     44         Secure,
     45     };
     46 
     47     // Converts the Type enum to a string.
     48     std::string_view ToString(Type type);
     49 
     50     // A stream definition, combining both type and path.
     51     // The well known values in Streams should be used by product code, while tests may directly create them.
     52     struct StreamDefinition
     53     {
     54         constexpr StreamDefinition(Type type, std::string_view name) : Type(type), Name(name) {}
     55 
     56         // The type of stream.
     57         Type Type;
     58 
     59         // The name is used as a file name in some situations.
     60         std::string_view Name;
     61     };
     62 
     63     // A setting stream; provides access to functionality on the stream.
     64     struct Stream
     65     {
     66         // The set of well known settings streams.
     67         // Changing these values can result in data loss.
     68 
     69         // The set of sources as defined by the user.
     70         constexpr static StreamDefinition UserSources{ Type::Secure, "user_sources"sv };
     71         // The metadata about all sources.
     72         constexpr static StreamDefinition SourcesMetadata{ Type::Standard, "sources_metadata"sv };
     73         // The primary user settings file.
     74         constexpr static StreamDefinition PrimaryUserSettings{ Type::UserFile, "settings.json"sv };
     75         // The backup user settings file.
     76         constexpr static StreamDefinition BackupUserSettings{ Type::UserFile, "settings.json.backup"sv };
     77         // The admin settings.
     78         constexpr static StreamDefinition AdminSettings{ Type::Secure, "admin_settings"sv };
     79 
     80         // Gets a Stream for the StreamDefinition.
     81         // If the stream is synchronized, attempts to Set the value can fail due to another writer
     82         // having changed the underlying stream.
     83         Stream(const StreamDefinition& streamDefinition);
     84 
     85         const StreamDefinition& Definition() const { return m_streamDefinition; }
     86 
     87         // Gets the stream if present.
     88         // If the setting stream does not exist, returns an empty value (see operator bool).
     89         std::unique_ptr<std::istream> Get();
     90 
     91         // Sets the stream to the given value.
     92         // Returns true if successful; false if the underlying stream has changed.
     93         [[nodiscard]] bool Set(std::string_view value);
     94 
     95         // Deletes the setting stream.
     96         void Remove();
     97 
     98         // Gets the name of the stream.
     99         std::string_view GetName() const;
    100 
    101         // Gets the path to the stream.
    102         std::filesystem::path GetPath() const;
    103 
    104     private:
    105         const StreamDefinition m_streamDefinition;
    106         std::unique_ptr<details::ISettingsContainer> m_container;
    107     };
    108 }