Remove itertools dependency

Collecting into Vec of &str and joining may even be faster according
to benchmarks:
https://gist.github.com/green-s/fbd0d374b290781ac9b3f8ff03e3245d

Cargo.lock

@@ -1101,7 +1101,6 @@ dependencies = [
  "humansize",
  "image",
  "indexmap",
- "itertools",
  "kamadak-exif",
  "lettre_email",
  "libc",

Cargo.toml

@@ -37,7 +37,6 @@ futures = "0.3"
 hex = "0.4.0"
 image = { version = "0.23.5", default-features=false, features = ["gif", "jpeg", "ico", "png", "pnm", "webp", "bmp"] }
 indexmap = "1.7"
-itertools = "0.10"
 kamadak-exif = "0.5"
 lettre_email = { git = "https://github.com/deltachat/lettre", branch = "master" }
 libc = "0.2"

src/chat.rs

@@ -7,7 +7,6 @@ use std::time::{Duration, SystemTime};
 use anyhow::{bail, ensure, format_err, Context as _, Result};
 use async_std::path::{Path, PathBuf};
 use deltachat_derive::{FromSql, ToSql};
-use itertools::Itertools;
 use serde::{Deserialize, Serialize};
 
 use crate::aheader::EncryptPreference;
@@ -2817,7 +2816,7 @@ pub async fn forward_msgs(context: &Context, msg_ids: &[MsgId], chat_id: ChatId)
             .query_map(
                 format!(
                     "SELECT id FROM msgs WHERE id IN({}) ORDER BY timestamp,id",
-                    msg_ids.iter().map(|_| "?").join(",")
+                    msg_ids.iter().map(|_| "?").collect::<Vec<&str>>().join(",")
                 ),
                 rusqlite::params_from_iter(msg_ids),
                 |row| row.get::<_, MsgId>(0),

src/configure.rs

@@ -8,7 +8,6 @@ mod server_params;
 use anyhow::{bail, ensure, Context as _, Result};
 use async_std::prelude::*;
 use async_std::task;
-use itertools::Itertools;
 use job::Action;
 use percent_encoding::{utf8_percent_encode, NON_ALPHANUMERIC};
 
@@ -682,7 +681,11 @@ async fn nicer_configuration_error(context: &Context, errors: Vec<ConfigurationE
         return first_err.msg.to_string();
     }
 
-    errors.iter().map(|e| e.to_string()).join("\n\n")
+    errors
+        .iter()
+        .map(|e| e.to_string())
+        .collect::<Vec<String>>()
+        .join("\n\n")
 }
 
 #[derive(Debug, thiserror::Error)]

src/contact.rs

@@ -5,7 +5,6 @@ use std::convert::{TryFrom, TryInto};
 use anyhow::{bail, ensure, Context as _, Result};
 use async_std::path::PathBuf;
 use deltachat_derive::{FromSql, ToSql};
-use itertools::Itertools;
 use once_cell::sync::Lazy;
 use regex::Regex;
 
@@ -1356,15 +1355,13 @@ pub fn addr_cmp(addr1: impl AsRef<str>, addr2: impl AsRef<str>) -> bool {
 
 fn split_address_book(book: &str) -> Vec<(&str, &str)> {
     book.lines()
+        .collect::<Vec<&str>>()
         .chunks(2)
         .into_iter()
-        .filter_map(|mut chunk| {
+        .filter_map(|chunk| {
-            let name = chunk.next().unwrap();
+            let name = chunk.get(0)?;
-            let addr = match chunk.next() {
+            let addr = chunk.get(1)?;
-                Some(a) => a,
+            Some((*name, *addr))
-                None => return None,
-            };
-            Some((name, addr))
         })
         .collect()
 }

src/dc_receive_imf.rs

@@ -4,7 +4,6 @@ use std::cmp::min;
 use std::convert::TryFrom;
 
 use anyhow::{bail, ensure, Context as _, Result};
-use itertools::join;
 use mailparse::SingleInfo;
 use num_traits::FromPrimitive;
 use once_cell::sync::Lazy;
@@ -1931,7 +1930,11 @@ async fn create_adhoc_group(
 /// are hidden in BCC. This group ID is sent by DC in the messages sent to this chat,
 /// so having the same ID prevents group split.
 async fn create_adhoc_grp_id(context: &Context, member_ids: &[u32]) -> Result<String> {
-    let member_ids_str = join(member_ids.iter().map(|x| x.to_string()), ",");
+    let member_ids_str = member_ids
+        .iter()
+        .map(|x| x.to_string())
+        .collect::<Vec<String>>()
+        .join(",");
     let member_cs = context
         .get_config(Config::ConfiguredAddr)
         .await?
@@ -2023,7 +2026,11 @@ async fn check_verified_properties(
     if to_ids.is_empty() {
         return Ok(());
     }
-    let to_ids_str = join(to_ids.iter().map(|x| x.to_string()), ",");
+    let to_ids_str = to_ids
+        .iter()
+        .map(|x| x.to_string())
+        .collect::<Vec<String>>()
+        .join(",");
 
     let rows = context
         .sql

src/job.rs

@@ -8,7 +8,6 @@ use std::future::Future;
 use anyhow::{bail, ensure, format_err, Context as _, Error, Result};
 use async_smtp::smtp::response::{Category, Code, Detail};
 use deltachat_derive::{FromSql, ToSql};
-use itertools::Itertools;
 use rand::{thread_rng, Rng};
 
 use crate::blob::BlobObject;
@@ -840,7 +839,7 @@ pub async fn kill_action(context: &Context, action: Action) -> Result<()> {
 async fn kill_ids(context: &Context, job_ids: &[u32]) -> Result<()> {
     let q = format!(
         "DELETE FROM jobs WHERE id IN({})",
-        job_ids.iter().map(|_| "?").join(",")
+        job_ids.iter().map(|_| "?").collect::<Vec<&str>>().join(",")
     );
     context
         .sql

src/param.rs

@@ -4,7 +4,6 @@ use std::str;
 
 use anyhow::{bail, Error};
 use async_std::path::PathBuf;
-use itertools::Itertools;
 use num_traits::FromPrimitive;
 use serde::{Deserialize, Serialize};
 
@@ -182,7 +181,7 @@ impl fmt::Display for Params {
                 f,
                 "{}={}",
                 *key as u8 as char,
-                value.split('\n').join("\n\n")
+                value.split('\n').collect::<Vec<&str>>().join("\n\n")
             )?;
         }
         Ok(())

src/simplify.rs

@@ -1,7 +1,5 @@
 //! # Simplify incoming plaintext.
 
-use itertools::Itertools;
-
 // protect lines starting with `--` against being treated as a footer.
 // for that, we insert a ZERO WIDTH SPACE (ZWSP, 0x200B);
 // this should be invisible on most systems and there is no need to unescape it again
@@ -158,6 +156,7 @@ fn remove_bottom_quote<'a>(lines: &'a [&str]) -> (&'a [&'a str], Option<String>)
                 s.strip_prefix('>')
                     .map_or(*s, |u| u.strip_prefix(' ').unwrap_or(u))
             })
+            .collect::<Vec<&str>>()
             .join("\n");
         if l_last > 1 && is_empty_line(lines[l_last - 1]) {
             l_last -= 1
@@ -204,6 +203,7 @@ fn remove_top_quote<'a>(lines: &'a [&str]) -> (&'a [&'a str], Option<String>) {
                         s.strip_prefix('>')
                             .map_or(*s, |u| u.strip_prefix(' ').unwrap_or(u))
                     })
+                    .collect::<Vec<&str>>()
                     .join("\n"),
             ),
         )

src/smtp/send.rs

@@ -6,7 +6,6 @@ use async_smtp::{EmailAddress, Envelope, SendableEmail, Transport};
 use crate::constants::DEFAULT_MAX_SMTP_RCPT_TO;
 use crate::context::Context;
 use crate::events::EventType;
-use itertools::Itertools;
 use std::time::Duration;
 
 pub type Result<T> = std::result::Result<T, Error>;
@@ -43,10 +42,14 @@ impl Smtp {
         }
 
         for recipients_chunk in recipients.chunks(chunk_size).into_iter() {
-            let recipients = recipients_chunk.to_vec();
+            let recipients_display = recipients_chunk
-            let recipients_display = recipients.iter().map(|x| x.to_string()).join(",");
+                .iter()
+                .map(|x| x.as_ref())
+                .collect::<Vec<&str>>()
+                .join(",");
 
-            let envelope = Envelope::new(self.from.clone(), recipients).map_err(Error::Envelope)?;
+            let envelope = Envelope::new(self.from.clone(), recipients_chunk.to_vec())
+                .map_err(Error::Envelope)?;
             let mail = SendableEmail::new(
                 envelope,
                 format!("{}", job_id), // only used for internal logging

src/summary.rs

@@ -9,7 +9,6 @@ use crate::message::{Message, MessageState};
 use crate::mimeparser::SystemMessage;
 use crate::param::Param;
 use crate::stock_str;
-use itertools::Itertools;
 use std::borrow::Cow;
 use std::fmt;
 
@@ -174,7 +173,7 @@ impl Message {
             summary_content
         };
 
-        summary.split_whitespace().join(" ")
+        summary.split_whitespace().collect::<Vec<&str>>().join(" ")
     }
 }
 

src/sync.rs

@@ -12,7 +12,6 @@ use crate::sync::SyncData::{AddQrToken, DeleteQrToken};
 use crate::token::Namespace;
 use crate::{chat, stock_str, token};
 use anyhow::Result;
-use itertools::Itertools;
 use lettre_email::mime::{self};
 use lettre_email::PartBuilder;
 use serde::{Deserialize, Serialize};
@@ -177,7 +176,10 @@ impl Context {
         } else {
             Ok(Some((
                 format!("{{\"items\":[\n{}\n]}}", serialized),
-                ids.iter().map(|x| x.to_string()).join(","),
+                ids.iter()
+                    .map(|x| x.to_string())
+                    .collect::<Vec<String>>()
+                    .join(","),
             )))
         }
     }