skeleton continues

src/lib.rs

@@ -1,3 +1,5 @@
+use std::{io::BufWriter, sync::Arc};
+
 pub(crate) mod prelude {
     #![allow(unused_imports)]
 
@@ -27,22 +29,20 @@ pub(crate) mod prelude {
 
 use prelude::*;
 
-use std::{
-    io::{BufRead, BufReader},
-    sync::Arc,
-};
-
 pub mod args;
 pub use args::Parser;
 mod color;
 pub use color::{CLI_ENABLE_COLOR, SHOULD_COLOR};
 pub mod line;
+mod nixcmd;
 pub use line::Line;
 pub mod source;
 pub use source::SourceLine;
 
 use serde::{Deserialize, Serialize};
 
+use crate::source::SourceFile;
+
 #[derive(Debug, Clone, PartialEq, Hash, Serialize, Deserialize)]
 pub struct DefinitionWithLocation {
     pub file: Box<Path>,
@@ -59,57 +59,29 @@ pub fn get_where(option_name: &str, configuration_nix: &Path) -> Result<Box<Path
     .into_iter()
     .map(ToOwned::to_owned)
     .collect();
-    let result = Command::new("nix-instantiate")
-        .arg("--eval")
-        .arg("--json")
-        .arg("--strict")
-        .arg("--expr")
-        .arg(expr)
-        .arg("-A")
-        .arg(format!("options.{}.definitionsWithLocations", option_name))
+
+    let attrpath = format!("options.{}.definitionsWithLocations", option_name);
+
+    let output = nixcmd::NixEvalExpr { expr, attrpath }
+        .into_command()
         .output_checked_utf8()?;
-    let stdout = result.stdout();
+    let stdout = output.stdout();
 
     let definitions: Box<[DefinitionWithLocation]> = serde_json::from_str(&stdout)?;
-    let last_location = definitions.last().unwrap();
-    let file = &*last_location.file;
-    dbg!(&file);
+    let last_location = definitions.into_iter().last().unwrap();
 
-    Ok(Box::from(file))
+    Ok(Box::from(last_location.file))
 }
 
 pub fn get_highest_prio(
     option_name: &str,
-    file_with_definition: &Path,
+    mut source: SourceFile,
 ) -> Result<SourceLine, BoxDynError> {
-    let mut file = File::options()
-        .read(true)
-        .write(true)
-        .create(false)
-        .custom_flags(libc::O_CLOEXEC)
-        .open(file_with_definition)?;
-
-    // TODO: seek and read backwards.
-
-    let mut lines = BufReader::new(&mut file)
-        .lines()
-        .enumerate()
-        .map(|(index, line_res)| {
-            line_res.map(|line| SourceLine {
-                line: Line::from_index(index as u64),
-                path: Arc::from(file_with_definition),
-                text: Arc::from(line),
-            })
-        })
-        .collect::<Result<Vec<SourceLine>, IoError>>()?;
-    lines.reverse();
-    let lines_reversed = lines;
-
     // Get the current highest priority.
 
     let expr: OsString = [
         OsStr::new("import <nixpkgs/nixos> { configuration = "),
-        file_with_definition.as_os_str(),
+        source.path().as_os_str(),
         OsStr::new("; }"),
     ]
     .into_iter()
@@ -117,41 +89,40 @@ pub fn get_highest_prio(
     .collect();
 
     // Get the highest priority, and the file its defined in.
-    let result = Command::new("nix-instantiate")
-        .arg("--eval")
-        .arg("--json")
-        .arg("--strict")
-        .arg("--expr")
-        .arg(expr)
-        .arg("-A")
-        .arg(format!("options.{}.highestPrio", option_name))
+    let attrpath = format!("options.{}.highestPrio", option_name);
+    let output = nixcmd::NixEvalExpr { expr, attrpath }
+        .into_command()
         .output_checked_utf8()?;
-    let stdout = result.stdout();
+    let stdout = output.stdout();
     let highest_prio = stdout.trim();
 
     let needle = format!("lib.mkOverride ({})", highest_prio);
-    eprintln!("looking for {needle:?}");
 
-    let line_with_current_highest = lines_reversed
+    let path = source.path();
+    let lines = source.lines()?;
+    let line = lines
         .iter()
-        .position(|line| {
-            eprintln!("looking for {needle} in {line}");
-
-            line.text.contains(&needle)
-        })
+        // We're more likely to find it at the end, so let's start there.
+        .rev()
+        .find(|&line| line.text.contains(&needle))
         .unwrap_or_else(|| {
             panic!(
                 "couldn't find override number {highest_prio} in {}",
-                file_with_definition.display()
+                path.display(),
             )
         });
 
-    let line = lines_reversed
-        .into_iter()
-        .nth(line_with_current_highest)
-        .unwrap();
-
-    eprintln!("found, on line index {}", line);
-
-    Ok(line)
+    Ok(line.clone())
+}
+
+pub fn write_next_prio(
+    mut source: SourceFile,
+    last_line_def: SourceLine,
+    new_prio: u64,
+) -> Result<(), BoxDynError> {
+    let lines = source.lines()?;
+
+    for line in lines {}
+
+    Ok(())
 }