Split off functional contact tools into its own crate (#5444)

I would like to implement
https://github.com/deltachat/deltachat-core-rust/issues/5422 in its own
crate, but it will depend on some functions that are in the `deltachat`
crate.

So, this PR extracts these functions into its own crate so that I can
add https://github.com/deltachat/deltachat-core-rust/issues/5422 into
the new crate.

deltachat-contact-tools/src/lib.rs

@@ -0,0 +1,280 @@
+//! Contact-related tools, like parsing vcards and sanitizing name and address
+
+#![forbid(unsafe_code)]
+#![warn(
+    unused,
+    clippy::correctness,
+    missing_debug_implementations,
+    missing_docs,
+    clippy::all,
+    clippy::wildcard_imports,
+    clippy::needless_borrow,
+    clippy::cast_lossless,
+    clippy::unused_async,
+    clippy::explicit_iter_loop,
+    clippy::explicit_into_iter_loop,
+    clippy::cloned_instead_of_copied
+)]
+#![cfg_attr(not(test), warn(clippy::indexing_slicing))]
+#![allow(
+    clippy::match_bool,
+    clippy::mixed_read_write_in_expression,
+    clippy::bool_assert_comparison,
+    clippy::manual_split_once,
+    clippy::format_push_string,
+    clippy::bool_to_int_with_if
+)]
+
+use std::fmt;
+use std::ops::Deref;
+
+use anyhow::bail;
+use anyhow::Result;
+use once_cell::sync::Lazy;
+use regex::Regex;
+
+/// Valid contact address.
+#[derive(Debug, Clone)]
+pub struct ContactAddress(String);
+
+impl Deref for ContactAddress {
+    type Target = str;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl AsRef<str> for ContactAddress {
+    fn as_ref(&self) -> &str {
+        &self.0
+    }
+}
+
+impl fmt::Display for ContactAddress {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
+impl ContactAddress {
+    /// Constructs a new contact address from string,
+    /// normalizing and validating it.
+    pub fn new(s: &str) -> Result<Self> {
+        let addr = addr_normalize(s);
+        if !may_be_valid_addr(&addr) {
+            bail!("invalid address {:?}", s);
+        }
+        Ok(Self(addr.to_string()))
+    }
+}
+
+/// Allow converting [`ContactAddress`] to an SQLite type.
+impl rusqlite::types::ToSql for ContactAddress {
+    fn to_sql(&self) -> rusqlite::Result<rusqlite::types::ToSqlOutput> {
+        let val = rusqlite::types::Value::Text(self.0.to_string());
+        let out = rusqlite::types::ToSqlOutput::Owned(val);
+        Ok(out)
+    }
+}
+
+/// Make the name and address
+pub fn sanitize_name_and_addr(name: &str, addr: &str) -> (String, String) {
+    static ADDR_WITH_NAME_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new("(.*)<(.*)>").unwrap());
+    if let Some(captures) = ADDR_WITH_NAME_REGEX.captures(addr.as_ref()) {
+        (
+            if name.is_empty() {
+                strip_rtlo_characters(
+                    &captures
+                        .get(1)
+                        .map_or("".to_string(), |m| normalize_name(m.as_str())),
+                )
+            } else {
+                strip_rtlo_characters(name)
+            },
+            captures
+                .get(2)
+                .map_or("".to_string(), |m| m.as_str().to_string()),
+        )
+    } else {
+        (strip_rtlo_characters(name), addr.to_string())
+    }
+}
+
+/// Normalize a name.
+///
+/// - Remove quotes (come from some bad MUA implementations)
+/// - Trims the resulting string
+///
+/// Typically, this function is not needed as it is called implicitly by `Contact::add_address_book`.
+pub fn normalize_name(full_name: &str) -> String {
+    let full_name = full_name.trim();
+    if full_name.is_empty() {
+        return full_name.into();
+    }
+
+    match full_name.as_bytes() {
+        [b'\'', .., b'\''] | [b'\"', .., b'\"'] | [b'<', .., b'>'] => full_name
+            .get(1..full_name.len() - 1)
+            .map_or("".to_string(), |s| s.trim().to_string()),
+        _ => full_name.to_string(),
+    }
+}
+
+const RTLO_CHARACTERS: [char; 5] = ['\u{202A}', '\u{202B}', '\u{202C}', '\u{202D}', '\u{202E}'];
+/// This method strips all occurrences of the RTLO Unicode character.
+/// [Why is this needed](https://github.com/deltachat/deltachat-core-rust/issues/3479)?
+pub fn strip_rtlo_characters(input_str: &str) -> String {
+    input_str.replace(|char| RTLO_CHARACTERS.contains(&char), "")
+}
+
+/// Returns false if addr is an invalid address, otherwise true.
+pub fn may_be_valid_addr(addr: &str) -> bool {
+    let res = EmailAddress::new(addr);
+    res.is_ok()
+}
+
+/// Returns address lowercased,
+/// with whitespace trimmed and `mailto:` prefix removed.
+pub fn addr_normalize(addr: &str) -> String {
+    let norm = addr.trim().to_lowercase();
+
+    if norm.starts_with("mailto:") {
+        norm.get(7..).unwrap_or(&norm).to_string()
+    } else {
+        norm
+    }
+}
+
+/// Compares two email addresses, normalizing them beforehand.
+pub fn addr_cmp(addr1: &str, addr2: &str) -> bool {
+    let norm1 = addr_normalize(addr1);
+    let norm2 = addr_normalize(addr2);
+
+    norm1 == norm2
+}
+
+///
+/// Represents an email address, right now just the `name@domain` portion.
+///
+/// # Example
+///
+/// ```
+/// use deltachat_contact_tools::EmailAddress;
+/// let email = match EmailAddress::new("someone@example.com") {
+///     Ok(addr) => addr,
+///     Err(e) => panic!("Error parsing address, error was {}", e),
+/// };
+/// assert_eq!(&email.local, "someone");
+/// assert_eq!(&email.domain, "example.com");
+/// assert_eq!(email.to_string(), "someone@example.com");
+/// ```
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct EmailAddress {
+    /// Local part of the email address.
+    pub local: String,
+
+    /// Email address domain.
+    pub domain: String,
+}
+
+impl fmt::Display for EmailAddress {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}@{}", self.local, self.domain)
+    }
+}
+
+impl EmailAddress {
+    /// Performs a dead-simple parse of an email address.
+    pub fn new(input: &str) -> Result<EmailAddress> {
+        if input.is_empty() {
+            bail!("empty string is not valid");
+        }
+        let parts: Vec<&str> = input.rsplitn(2, '@').collect();
+
+        if input
+            .chars()
+            .any(|c| c.is_whitespace() || c == '<' || c == '>')
+        {
+            bail!("Email {:?} must not contain whitespaces, '>' or '<'", input);
+        }
+
+        match &parts[..] {
+            [domain, local] => {
+                if local.is_empty() {
+                    bail!("empty string is not valid for local part in {:?}", input);
+                }
+                if domain.is_empty() {
+                    bail!("missing domain after '@' in {:?}", input);
+                }
+                if domain.ends_with('.') {
+                    bail!("Domain {domain:?} should not contain the dot in the end");
+                }
+                Ok(EmailAddress {
+                    local: (*local).to_string(),
+                    domain: (*domain).to_string(),
+                })
+            }
+            _ => bail!("Email {:?} must contain '@' character", input),
+        }
+    }
+}
+
+impl rusqlite::types::ToSql for EmailAddress {
+    fn to_sql(&self) -> rusqlite::Result<rusqlite::types::ToSqlOutput> {
+        let val = rusqlite::types::Value::Text(self.to_string());
+        let out = rusqlite::types::ToSqlOutput::Owned(val);
+        Ok(out)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_contact_address() -> Result<()> {
+        let alice_addr = "alice@example.org";
+        let contact_address = ContactAddress::new(alice_addr)?;
+        assert_eq!(contact_address.as_ref(), alice_addr);
+
+        let invalid_addr = "<> foobar";
+        assert!(ContactAddress::new(invalid_addr).is_err());
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_emailaddress_parse() {
+        assert_eq!(EmailAddress::new("").is_ok(), false);
+        assert_eq!(
+            EmailAddress::new("user@domain.tld").unwrap(),
+            EmailAddress {
+                local: "user".into(),
+                domain: "domain.tld".into(),
+            }
+        );
+        assert_eq!(
+            EmailAddress::new("user@localhost").unwrap(),
+            EmailAddress {
+                local: "user".into(),
+                domain: "localhost".into()
+            }
+        );
+        assert_eq!(EmailAddress::new("uuu").is_ok(), false);
+        assert_eq!(EmailAddress::new("dd.tt").is_ok(), false);
+        assert!(EmailAddress::new("tt.dd@uu").is_ok());
+        assert!(EmailAddress::new("u@d").is_ok());
+        assert!(EmailAddress::new("u@d.").is_err());
+        assert!(EmailAddress::new("u@d.t").is_ok());
+        assert_eq!(
+            EmailAddress::new("u@d.tt").unwrap(),
+            EmailAddress {
+                local: "u".into(),
+                domain: "d.tt".into(),
+            }
+        );
+        assert!(EmailAddress::new("u@tt").is_ok());
+        assert_eq!(EmailAddress::new("@d.tt").is_ok(), false);
+    }
+}