Move nix json types to extra crate

Signed-off-by: Marcel Müller <neikos@neikos.email>

nixie-build/Cargo.toml

@@ -7,3 +7,11 @@ authors.workspace = true
 readme.workspace = true
 
 [dependencies]
+thiserror.workspace = true
+displaydoc.workspace = true
+serde.workspace = true
+serde_json.workspace = true
+petgraph.workspace = true
+tokio.workspace = true
+futures.workspace = true
+nix-json.workspace = true

nixie-build/src/lib.rs

@@ -1,14 +1,265 @@
-pub fn add(left: u64, right: u64) -> u64 {
-    left + right
+use std::collections::HashMap;
+use std::fmt::Write;
+use std::process::Stdio;
+
+use futures::FutureExt;
+use futures::StreamExt;
+use futures::stream::BoxStream;
+use nix_json::NixBuildLogLine;
+use nix_json::RawNixDerivationInfoOutput;
+use petgraph::Directed;
+use petgraph::Graph;
+use petgraph::prelude::NodeIndex;
+use tokio::io::AsyncBufReadExt;
+use tokio::process::Command;
+
+#[derive(Debug)]
+pub struct NixBuildResult {
+    derivation: String,
+    log: String,
+    success: bool,
+}
+
+impl NixBuildResult {
+    pub fn derivation(&self) -> &str {
+        &self.derivation
+    }
+
+    pub fn log(&self) -> &str {
+        &self.log
+    }
+
+    pub fn success(&self) -> bool {
+        self.success
+    }
+}
+
+#[derive(Debug)]
+pub enum NixBuildError {}
+
+pub trait NixInProgressBuild {
+    fn next_log_line(
+        &mut self,
+    ) -> impl Future<Output = Option<Result<NixBuildLogLine, NixBuildError>>>;
+}
+
+pub trait NixBackend {
+    type InProgressBuild<'b>: NixInProgressBuild
+    where
+        Self: 'b;
+
+    fn start_build(
+        &self,
+        derivation: &str,
+    ) -> impl Future<Output = Result<Self::InProgressBuild<'_>, NixBuildError>>;
+
+    fn get_needed_builds(
+        &self,
+        derivation: &str,
+    ) -> impl Future<Output = Result<NixBuildGraph, NixBuildError>>;
+}
+
+pub struct NixCliBackend {
+    command_path: String,
+}
+
+pub struct NixCliBackendBuild {
+    child: BoxStream<'static, String>,
+}
+
+impl NixInProgressBuild for NixCliBackendBuild {
+    fn next_log_line(
+        &mut self,
+    ) -> impl Future<Output = Option<Result<NixBuildLogLine, NixBuildError>>> {
+        self.child.next().map(|out| {
+            out.map(|line| Ok(serde_json::from_str(line.trim_start_matches("@nix ")).unwrap()))
+        })
+    }
+}
+
+impl NixBackend for NixCliBackend {
+    type InProgressBuild<'b> = NixCliBackendBuild;
+
+    fn start_build(
+        &self,
+        derivation: &str,
+    ) -> impl Future<Output = Result<Self::InProgressBuild<'_>, NixBuildError>> {
+        async move {
+            let mut cmd = Command::new(&self.command_path)
+                .args(["build", "--log-format", "internal-json"])
+                .arg(derivation)
+                .stdout(Stdio::piped())
+                .stderr(Stdio::piped())
+                .spawn()
+                .unwrap();
+
+            let init = cmd.stderr.take().unwrap();
+            Ok(NixCliBackendBuild {
+                child: futures::stream::unfold(
+                    tokio::io::BufReader::new(init),
+                    move |mut state| async move {
+                        let mut buffer = String::new();
+                        let num_bytes = state.read_line(&mut buffer).await.unwrap();
+
+                        if num_bytes == 0 {
+                            None
+                        } else {
+                            Some((std::mem::take(&mut buffer), state))
+                        }
+                    },
+                )
+                .boxed(),
+            })
+        }
+    }
+
+    fn get_needed_builds(
+        &self,
+        derivation: &str,
+    ) -> impl Future<Output = Result<NixBuildGraph, NixBuildError>> {
+        async move {
+            let cmd = Command::new(&self.command_path)
+                .args(["derivation", "show", "--recursive"])
+                .arg(derivation)
+                .output()
+                .await
+                .unwrap();
+
+            let output: RawNixDerivationInfoOutput = serde_json::from_slice(&cmd.stdout).unwrap();
+
+            let mut build_graph = NixBuildGraph::default();
+
+            for (path, _info) in output.info() {
+                let internal_id = build_graph.dependencies.add_node(path.to_string());
+                build_graph.build_infos.insert(
+                    path.to_string(),
+                    NixBuildInfo {
+                        internal_id,
+                        present_in_binary_cache: false,
+                    },
+                );
+            }
+
+            for (path, info) in output.info() {
+                let build_info = &build_graph.build_infos[path];
+                let cur_node = build_info.internal_id;
+
+                for (dep_path, _dep_info) in info.input_derivations() {
+                    let other_node = build_graph.build_infos[dep_path].internal_id;
+                    build_graph.dependencies.add_edge(
+                        cur_node,
+                        other_node,
+                        NixBuildOutput {
+                            output_name: String::new(),
+                        },
+                    );
+                }
+            }
+
+            Ok(build_graph)
+        }
+    }
+}
+
+pub struct NixBuilder<B> {
+    backend: B,
+}
+
+#[derive(Debug, Clone)]
+pub struct NixBuildInfo {
+    internal_id: NodeIndex<usize>,
+    present_in_binary_cache: bool,
+}
+
+#[derive(Debug)]
+pub struct NixBuildOutput {
+    output_name: String,
+}
+
+#[derive(Debug, Default)]
+pub struct NixBuildGraph {
+    build_infos: HashMap<String, NixBuildInfo>,
+    dependencies: Graph<String, NixBuildOutput, Directed, usize>,
+}
+
+impl NixBuildGraph {
+    fn get_non_binary_builds(&self) -> impl Iterator<Item = (String, NixBuildInfo)> {
+        self.build_infos
+            .iter()
+            .filter(|(_, value)| !value.present_in_binary_cache)
+            .map(|(key, value)| (key.clone(), value.clone()))
+    }
+}
+
+impl<B> NixBuilder<B>
+where
+    B: NixBackend,
+{
+    pub async fn build(
+        &self,
+        derivation: String,
+    ) -> Result<HashMap<String, NixBuildResult>, NixBuildError> {
+        let needed_builds = self.backend.get_needed_builds(&derivation).await?;
+        let mut started_build = self.backend.start_build(&derivation).await?;
+
+        let mut actually_built =
+            HashMap::from_iter(needed_builds.get_non_binary_builds().map(|(k, _v)| {
+                (
+                    k.clone(),
+                    NixBuildResult {
+                        derivation: k,
+                        log: String::new(),
+                        success: false,
+                    },
+                )
+            }));
+
+        let mut id_to_derivation = HashMap::new();
+
+        while let Some(next_log_line) = started_build.next_log_line().await {
+            let next_log_line = next_log_line?;
+
+            if let NixBuildLogLine::Start(start_log) = next_log_line {
+                if start_log.kind == Some(105) {
+                    id_to_derivation.insert(
+                        start_log.id,
+                        start_log.fields[0].as_str().unwrap().to_string(),
+                    );
+                }
+            } else if let NixBuildLogLine::Result(result) = next_log_line {
+                if result.kind == 101 {
+                    if let Some(build) = actually_built.get_mut(&id_to_derivation[&result.id]) {
+                        writeln!(&mut build.log, "{}", result.fields[0].as_str().unwrap()).unwrap()
+                    } else {
+                        panic!("Could not find correct id");
+                    }
+                }
+            }
+        }
+
+        actually_built.retain(|_k, v| !v.log.is_empty());
+
+        Ok(actually_built)
+    }
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
 
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
+    #[tokio::test]
+    async fn check_unpure() {
+        let builder = NixBuilder {
+            backend: NixCliBackend {
+                command_path: String::from("nix"),
+            },
+        };
+
+        let infos = builder
+            .build(".#checks.x86_64-linux.crate-fmt".to_string())
+            .await
+            .unwrap();
+
+        println!("Got: {infos:#?}");
     }
 }