Add ICRC-21 as it is considered approved and finalized

ICRCs/ICRC-21/ICRC-21.did

@@ -0,0 +1,173 @@
+// Canister interface specification for ICRC-21.
+// See https://github.com/dfinity/wg-identity-authentication/blob/main/topics/ICRC-21/icrc_21_consent_msg.md
+
+type icrc21_consent_message_metadata = record {
+    // BCP-47 language tag. See https://www.rfc-editor.org/rfc/bcp/bcp47.txt
+    language: text;
+
+    // The users local timezone offset in minutes from UTC.
+    // Applicable when converting timestamps to human-readable format.
+    //
+    // If absent in the request, the canister should fallback to the UTC timezone when creating the consent message.
+    // If absent in the response, the canister is indicating that the consent message is not timezone sensitive.
+    utc_offset_minutes: opt int16;
+};
+
+type icrc21_consent_message_spec = record {
+    // Metadata of the consent message.
+    metadata: icrc21_consent_message_metadata;
+
+    // Information about the device responsible for presenting the consent message to the user.
+    // If absent in the request, the canister should fallback to one of the values defined in this spec (ICRC-21).
+    device_spec: opt variant {
+        // A generic display able to handle large documents and do line wrapping and pagination / scrolling.
+        // Text must be Markdown formatted, no external resources (e.g. images) are allowed.
+        GenericDisplay;
+        // A simple display able to handle multiple fields with a title and content.
+        // It's able to do line wrapping and splits fields into multiple pages if they're too long.
+        // Text must be plain text without any embedded formatting elements.
+        FieldsDisplay;
+    };
+};
+
+type icrc21_consent_message_request = record {
+    // Method name of the canister call.
+    method: text;
+    // Argument of the canister call.
+    arg: blob;
+    // User preferences with regards to the consent message presented to the end-user.
+    user_preferences: icrc21_consent_message_spec;
+};
+
+type TokenAmount = record {
+    decimals: nat8;
+    amount: nat64;
+    symbol: text;
+};
+
+type TimestampSeconds = record {
+    amount: nat64;
+};
+
+type DurationSeconds = record {
+    amount: nat64;
+};
+
+type TextValue = record {
+    content: text;
+};
+
+type Value = variant {
+    TokenAmount: TokenAmount;
+    TimestampSeconds: TimestampSeconds;
+    DurationSeconds: DurationSeconds;
+    Text: TextValue;
+};
+
+type icrc21_consent_message = variant {
+    // Message for a generic display able to handle large documents and do proper line wrapping and pagination / scrolling.
+    // Uses Markdown formatting, no external resources (e.g. images) are allowed.
+    GenericDisplayMessage: text;
+    // Message for a simple display able to handle multiple fields title and content.
+    // It's able to do line wrapping and splits fields into multiple pages if they're too long.
+    // Uses plain text, without any embedded formatting elements.
+    FieldsDisplayMessage: record {
+        // Context and type of canister call, accurate and concise e.g. Send ICP
+        intent: text;
+        // Canister call fields for review e.g. Amount 234.73 ICP
+        fields: vec record { text; Value };
+    };
+};
+
+type icrc21_consent_info = record {
+    // Consent message describing in a human-readable format what the call will do.
+    //
+    // The message should adhere as close as possible to the user_preferences specified in the consent_message_spec
+    // of the icrc21_consent_message_request.
+    // If the message is not available for the given user_preferences any fallback message should be used. Providing a
+    // message should be preferred over sending an icrc21_error.
+    // The metadata must match the consent_message provided.
+    //
+    // The message should be short and concise.
+    // It should only contain information that is:
+    // * relevant to the user
+    // * relevant given the canister call argument
+    //
+    // The message must fit the following context shown to
+    // the user on the signer UI:
+    // ┌─────────────────────────────────┐
+    // │  Approve the following action?  │
+    // │  ┌───────────────────────────┐  │
+    // │  │    <consent_message>      │  │
+    // │  └───────────────────────────┘  │
+    // │  ┌───────────┐   ┌───────────┐  │
+    // │  │  Reject   │   │  Approve  │  │
+    // │  └───────────┘   └───────────┘  │
+    // └─────────────────────────────────┘
+    consent_message: icrc21_consent_message;
+    // Metadata of the consent_message.
+    metadata: icrc21_consent_message_metadata;
+};
+
+type icrc21_error_info = record {
+    // Human readable technical description of the error intended for developers, not the end-user.
+    description: text;
+};
+
+type icrc21_error = variant {
+    // The canister does not support this call (i.e. it will lead to a rejection or error response).
+    // Reasons might be (non-exhaustive list):
+    // * the canister call is malformed (e.g. wrong method name, argument cannot be decoded)
+    // * the arguments exceed certain bounds
+    //
+    // The developer should provide more information about the error using the description in icrc21_error_info.
+    UnsupportedCanisterCall: icrc21_error_info;
+
+    // The canister cannot produce a consent message for this call.
+    // Reasons might be (non-exhaustive list):
+    // * it is an internal call not intended for end-users
+    // * the canister developer has not yet implemented a consent message for this call
+    //
+    // The developer should provide more information about the error using the description in icrc21_error_info.
+    ConsentMessageUnavailable: icrc21_error_info;
+
+    // The canister did not provide a consent message for because payment was missing or insufficient.
+    //
+    // This error is used to account for payment extensions to be added in the future:
+    // While small consent messages are easy and cheap to provide, this might not generally be the case for all consent
+    // messages. To avoid future breaking changes, when introducing a payment flow, this error is already introduced
+    // even though there no standardized payment flow yet.
+    InsufficientPayment: icrc21_error_info;
+
+    // Any error not covered by the above variants.
+    GenericError: record {
+       // Machine parsable error. Can be chosen by the target canister but should indicate the error category.
+       error_code: nat;
+       // Human readable technical description of the error intended for developers, not the end-user.
+       description: text;
+   };
+};
+
+type icrc21_consent_message_response = variant {
+    // The call is ok, consent message is provided.
+    Ok: icrc21_consent_info;
+    // The call is not ok, error is provided.
+    Err: icrc21_error;
+};
+
+service : {
+    // Returns a human-readable consent message for the given canister call.
+    //
+    // This call must not require authentication (i.e. must be available for the anonymous sender).
+    // If the call is made with a non-anonymous identity, the response may be tailored to the identity.
+    //
+    // This is currently an update call. As soon as secure (replicated) query calls are available, this will be changed to such a replicated query call.
+    icrc21_canister_call_consent_message: (icrc21_consent_message_request) -> (icrc21_consent_message_response);
+
+    // Returns a list of supported standards that this canister implements.
+    // The result must include an entry for ICRC-21:
+    // record { name = "ICRC-21"; url = "https://github.com/dfinity/ICRC/blob/main/ICRCs/ICRC-21/ICRC-21.md" }
+    //
+    // See ICRC-10 for more information: https://github.com/dfinity/ICRC/blob/main/ICRCs/ICRC-10/ICRC-10.md
+    icrc10_supported_standards : () -> (vec record { name : text; url : text }) query;
+}