put matrix & discord functionality behind gates

serenity and matrix-sdk pull in quite a lot of dependencies, which for a
minimal use of ezau might not be wanted. Therefore, we now disable those
parts by default, and the user has to opt-in into building ezau with
Discord or Matrix functionality.

5 files changed, 67 insertions, 7 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 47e2400..a812cfb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1475,6 +1475,8 @@ dependencies = [
 [[package]]
 name = "olm-sys"
 version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "108c8902295791150d37f0d7b200de1fdd759f34bf479dfdc63c19de8c84c584"
 dependencies = [
  "cmake",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index c0d5e9e..78abccd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,10 @@ license = "MIT"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[features]
+im-matrix = ["matrix-sdk", "tokio"]
+im-discord = ["serenity", "tokio"]
+
 [dependencies]
 clap = "3.0.0-beta.1"
 log = "0.4.8"
@@ -14,15 +18,16 @@ pretty_env_logger = "0.4.0"
 anyhow = "1.0.31"
 evtclib = "0.5.0"
 reqwest = { version = "0.10.6", features = ["json", "blocking"] }
-serde = "1.0.111"
+serde = { version = "1.0.111", features = ["derive"] }
 chrono = "0.4.11"
 notify = "4.0.15"
 regex = "1.3.9"
 zip = "0.5.5"
 toml = "0.5.6"
-tokio = { version = "0.2", features = ["rt-core"] }
-matrix-sdk = "0.2.0"
 itertools = "0.10.0"
+# Optional features for IM integration
+tokio = { version = "0.2", features = ["rt-core"], optional = true }
+matrix-sdk = { version = "0.2.0", optional = true }
 
 [dependencies.serenity]
 default-features = false
@@ -37,3 +42,4 @@ features = [
     "rustls_backend",
 ]
 version = "0.9"
+optional = true
diff --git a/src/discord.rs b/src/discord.rs
index ea0ea36..c98a6c7 100644
--- a/src/discord.rs
+++ b/src/discord.rs
@@ -11,7 +11,7 @@ use tokio::runtime::Runtime;
 use log::info;
 
 use super::categories::Categorizable;
-use super::logbag::{LogBag, state_emoji};
+use super::logbag::{state_emoji, LogBag};
 
 const MAX_HOURS: i64 = 5;
 const MAX_MESSAGE_LENGTH: usize = 2000;
diff --git a/src/logbag.rs b/src/logbag.rs
index f94b80a..362bee5 100644
--- a/src/logbag.rs
+++ b/src/logbag.rs
@@ -14,15 +14,16 @@ pub struct LogBag {
     data: Vec<(String, Vec<String>)>,
 }
 
+// Conditional compilation makes it hard to really use all the code, so we just allow dead code
+// here locally.
+#[allow(dead_code)]
 impl LogBag {
     /// Construct a new, empty [`LogBag`].
-    #[cfg(test)]
     pub fn new() -> Self {
         LogBag { data: Vec::new() }
     }
 
     /// Return an iterator over all available categories.
-    #[cfg(test)]
     pub fn categories(&self) -> impl Iterator<Item = &str> {
         self.data.iter().map(|x| &x.0 as &str)
     }
diff --git a/src/main.rs b/src/main.rs
index ab40d86..55bd637 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -7,7 +7,7 @@ use std::{
     time::Duration,
 };
 
-use anyhow::{anyhow, Context, Result};
+use anyhow::{anyhow, bail, Context, Result};
 use clap::Clap;
 use evtclib::{Compression, Encounter, Log};
 use log::{debug, error, info, warn};
@@ -20,8 +20,11 @@ mod categories;
 use categories::Categorizable;
 mod config;
 use config::Config;
+#[cfg(feature = "im-discord")]
 mod discord;
+#[cfg(any(feature = "im-discord", feature = "im-matrix"))]
 mod logbag;
+#[cfg(feature = "im-matrix")]
 mod matrix;
 
 const DPS_REPORT_API: &str = "https://dps.report/uploadContent";
@@ -75,6 +78,8 @@ fn main() {
 
 fn inner_main(opts: &Opts) -> Result<()> {
     let config = config::load(&opts.config).context("Could not load configuration")?;
+    sanity_check(&config)?;
+
     match &opts.subcmd {
         SubCommand::Watch(w) => watch(w, &config)?,
         SubCommand::Upload(u) => {
@@ -244,3 +249,49 @@ fn upload_log(file: &Path) -> Result<String> {
         .json()?;
     Ok(resp.permalink)
 }
+
+fn sanity_check(config: &Config) -> Result<()> {
+    if config.discord.is_some() && !cfg!(feature = "im-discord") {
+        bail!(
+            "Discord is configured but ezau was built without Discord support. \
+            Please enable the `im-discord` feature or adjust your configuration \
+            to continue."
+        );
+    }
+    if config.matrix.is_some() && !cfg!(feature = "im-matrix") {
+        bail!(
+            "Matrix is configured but ezau was built without Matrix support. \
+            Please enable the `im-matrix` feature or adjust your configuration \
+            to continue."
+        );
+    }
+    Ok(())
+}
+
+// Dummy modules for when the features are disabled
+#[cfg(not(feature = "im-discord"))]
+mod discord {
+    use super::{Log, Result};
+    use anyhow::bail;
+
+    /// Stub, enable the `im-discord` feature to use this function.
+    pub fn post_link(_: &str, _: u64, _: &Log, _: &str) -> Result<()> {
+        bail!("Discord feature is disabled in this build!")
+    }
+}
+
+#[cfg(not(feature = "im-matrix"))]
+mod matrix {
+    use super::{Log, Result};
+    use anyhow::bail;
+    pub struct MatrixUser;
+    impl From<super::config::Matrix> for MatrixUser {
+        fn from(_: super::config::Matrix) -> MatrixUser {
+            MatrixUser
+        }
+    }
+    /// Stub, enable the `im-matrix` feature to use this function.
+    pub fn post_link(_: MatrixUser, _: &str, _: &Log, _: &str) -> Result<()> {
+        bail!("Matrix feature is disabled in this build!")
+    }
+}