Parse QR codes without using Param

Param should only be used to parse dictionaries stored in SQL database, not external data.

Since Param parser has been extended to escape newlines with newlines, QR-codes parser started to treat && as escaped &, which is wrong.

This change also uses String keys like "n" for "name" instead of completely unrelated constants like Param::SetLongitude.

src/param.rs

@@ -127,15 +127,6 @@ pub enum Param {
     /// For Chats
     Devicetalk = b'D',
 
-    /// For QR
-    Auth = b's',
-
-    /// For QR
-    GroupId = b'x',
-
-    /// For QR
-    GroupName = b'g',
-
     /// For MDN-sending job
     MsgId = b'I',
 }
@@ -431,14 +422,6 @@ mod tests {
         assert_eq!(params.to_string().parse::<Params>().unwrap(), params);
     }
 
-    #[test]
-    fn test_regression() {
-        let p1: Params = "a=cli%40deltachat.de\nn=\ni=TbnwJ6lSvD5\ns=0ejvbdFSQxB"
-            .parse()
-            .unwrap();
-        assert_eq!(p1.get(Param::Forwarded).unwrap(), "cli%40deltachat.de");
-    }
-
     #[async_std::test]
     async fn test_params_file_fs_path() {
         let t = TestContext::new().await;

src/qr.rs

@@ -4,6 +4,7 @@ use anyhow::{bail, ensure, format_err, Error};
 use once_cell::sync::Lazy;
 use percent_encoding::percent_decode_str;
 use serde::Deserialize;
+use std::collections::BTreeMap;
 
 use crate::chat;
 use crate::config::Config;
@@ -13,7 +14,6 @@ use crate::context::Context;
 use crate::key::Fingerprint;
 use crate::lot::{Lot, LotState};
 use crate::message::Message;
-use crate::param::{Param, Params};
 use crate::peerstate::Peerstate;
 
 const OPENPGP4FPR_SCHEME: &str = "OPENPGP4FPR:"; // yes: uppercase
@@ -93,16 +93,18 @@ async fn decode_openpgp(context: &Context, qr: &str) -> Lot {
         }
     };
 
-    // replace & with \n to match expected param format
-    let fragment = fragment.replace('&', "\n");
+    let param: BTreeMap<&str, &str> = fragment
+        .split('&')
+        .filter_map(|s| {
+            if let [key, value] = s.splitn(2, '=').collect::<Vec<_>>()[..] {
+                Some((key, value))
+            } else {
+                None
+            }
+        })
+        .collect();
 
-    // Then parse the parameters
-    let param: Params = match fragment.parse() {
-        Ok(params) => params,
-        Err(err) => return err.into(),
-    };
-
-    let addr = if let Some(addr) = param.get(Param::Forwarded) {
+    let addr = if let Some(addr) = param.get("a") {
         match normalize_address(addr) {
             Ok(addr) => Some(addr),
             Err(err) => return err.into(),
@@ -112,7 +114,7 @@ async fn decode_openpgp(context: &Context, qr: &str) -> Lot {
     };
 
     // what is up with that param name?
-    let name = if let Some(encoded_name) = param.get(Param::SetLongitude) {
+    let name = if let Some(encoded_name) = param.get("n") {
         let encoded_name = encoded_name.replace("+", "%20"); // sometimes spaces are encoded as `+`
         match percent_decode_str(&encoded_name).decode_utf8() {
             Ok(name) => name.to_string(),
@@ -122,12 +124,12 @@ async fn decode_openpgp(context: &Context, qr: &str) -> Lot {
         "".to_string()
     };
 
-    let invitenumber = param.get(Param::ProfileImage).map(|s| s.to_string());
-    let auth = param.get(Param::Auth).map(|s| s.to_string());
-    let grpid = param.get(Param::GroupId).map(|s| s.to_string());
+    let invitenumber = param.get("i").map(|s| s.to_string());
+    let auth = param.get("s").map(|s| s.to_string());
+    let grpid = param.get("x").map(|s| s.to_string());
 
     let grpname = if grpid.is_some() {
-        if let Some(encoded_name) = param.get(Param::GroupName) {
+        if let Some(encoded_name) = param.get("g") {
             let encoded_name = encoded_name.replace("+", "%20"); // sometimes spaces are encoded as `+`
             match percent_decode_str(&encoded_name).decode_utf8() {
                 Ok(name) => Some(name.to_string()),
@@ -563,6 +565,7 @@ mod tests {
         assert_eq!(res.get_text1().unwrap(), "test ? test !");
 
         // Test it again with lowercased "openpgp4fpr:" uri scheme
+        let ctx = TestContext::new().await;
         let res = check_qr(
             &ctx.ctx,
             "openpgp4fpr:79252762C34C5096AF57958F4FC3D21A81B0F0A7#a=cli%40deltachat.de&g=test%20%3F+test%20%21&x=h-0oKQf2CDK&i=9JEXlxAqGM0&s=0V7LzL9cxRL"
@@ -603,6 +606,21 @@ mod tests {
         let contact = Contact::get_by_id(&ctx.ctx, res.get_id()).await.unwrap();
         assert_eq!(contact.get_addr(), "cli@deltachat.de");
         assert_eq!(contact.get_name(), "Jörn P. P.");
+
+        // Regression test
+        let ctx = TestContext::new().await;
+        let res = check_qr(
+            &ctx.ctx,
+            "openpgp4fpr:79252762C34C5096AF57958F4FC3D21A81B0F0A7#a=cli%40deltachat.de&n=&i=TbnwJ6lSvD5&s=0ejvbdFSQxB"
+        ).await;
+
+        println!("{:?}", res);
+        assert_eq!(res.get_state(), LotState::QrAskVerifyContact);
+        assert_ne!(res.get_id(), 0);
+
+        let contact = Contact::get_by_id(&ctx.ctx, res.get_id()).await.unwrap();
+        assert_eq!(contact.get_addr(), "cli@deltachat.de");
+        assert_eq!(contact.get_name(), "");
     }
 
     #[async_std::test]