Move QrInvite out to a submodle

src/securejoin/qrinvite.rs

@@ -0,0 +1,115 @@
+//! Supporting code for the QR-code invite.
+//!
+//! QR-codes are decoded into a more general-purpose [`Lot`] struct normally, this struct is
+//! so general it is not even specific to QR-codes.  This makes working with it rather hard,
+//! so here we have a wrapper type that specifically deals weith Secure-Join QR-codes so
+//! that the Secure-Join code can have many more guarantees when dealing with this.
+
+use std::convert::TryFrom;
+
+use anyhow::Result;
+
+use crate::key::{Fingerprint, FingerprintError};
+use crate::lot::{Lot, LotState};
+
+/// Represents the data from a QR-code scan.
+///
+/// There are methods to conveniently access fields present in both variants.
+#[derive(Debug, Clone)]
+pub enum QrInvite {
+    Contact {
+        contact_id: u32,
+        fingerprint: Fingerprint,
+        invitenumber: String,
+        authcode: String,
+    },
+    Group {
+        contact_id: u32,
+        fingerprint: Fingerprint,
+        name: String,
+        grpid: String,
+        invitenumber: String,
+        authcode: String,
+    },
+}
+
+impl QrInvite {
+    /// The contact ID of the inviter.
+    ///
+    /// The actual QR-code contains a URL-encoded email address, but upon scanning this is
+    /// currently translated to a contact ID.
+    pub fn contact_id(&self) -> u32 {
+        match self {
+            Self::Contact { contact_id, .. } | Self::Group { contact_id, .. } => *contact_id,
+        }
+    }
+
+    /// The fingerprint of the inviter.
+    pub fn fingerprint(&self) -> &Fingerprint {
+        match self {
+            Self::Contact { fingerprint, .. } | Self::Group { fingerprint, .. } => &fingerprint,
+        }
+    }
+
+    /// The `INVITENUMBER` of the setup-contact/secure-join protocol.
+    pub fn invitenumber(&self) -> &str {
+        match self {
+            Self::Contact { invitenumber, .. } | Self::Group { invitenumber, .. } => &invitenumber,
+        }
+    }
+
+    /// The `AUTH` code of the setup-contact/secure-join protocol.
+    pub fn authcode(&self) -> &str {
+        match self {
+            Self::Contact { authcode, .. } | Self::Group { authcode, .. } => &authcode,
+        }
+    }
+}
+
+impl TryFrom<Lot> for QrInvite {
+    type Error = QrError;
+
+    fn try_from(lot: Lot) -> Result<Self, Self::Error> {
+        if lot.state != LotState::QrAskVerifyContact && lot.state != LotState::QrAskVerifyGroup {
+            return Err(QrError::UnsupportedProtocol);
+        }
+        let fingerprint = lot.fingerprint.ok_or(QrError::MissingFingerprint)?;
+        let invitenumber = lot.invitenumber.ok_or(QrError::MissingInviteNumber)?;
+        let authcode = lot.auth.ok_or(QrError::MissingAuthCode)?;
+        match lot.state {
+            LotState::QrAskVerifyContact => Ok(QrInvite::Contact {
+                contact_id: lot.id,
+                fingerprint,
+                invitenumber,
+                authcode,
+            }),
+            LotState::QrAskVerifyGroup => Ok(QrInvite::Group {
+                contact_id: lot.id,
+                fingerprint,
+                name: lot.text1.ok_or(QrError::MissingGroupName)?,
+                grpid: lot.text2.ok_or(QrError::MissingGroupId)?,
+                invitenumber,
+                authcode,
+            }),
+            _ => Err(QrError::UnsupportedProtocol),
+        }
+    }
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum QrError {
+    #[error("Unsupported protocol in QR-code")]
+    UnsupportedProtocol,
+    #[error("Failed to read fingerprint")]
+    InvalidFingerprint(#[from] FingerprintError),
+    #[error("Missing fingerprint")]
+    MissingFingerprint,
+    #[error("Missing invitenumber")]
+    MissingInviteNumber,
+    #[error("Missing auth code")]
+    MissingAuthCode,
+    #[error("Missing group name")]
+    MissingGroupName,
+    #[error("Missing group id")]
+    MissingGroupId,
+}