implement GNUish '%'-based inference rules

3 files changed, 106 insertions, 37 deletions

diff --git a/src/makefile/inference_rules.rs b/src/makefile/inference_rules.rs
index 3d18730..dfbb07c 100644
--- a/src/makefile/inference_rules.rs
+++ b/src/makefile/inference_rules.rs
@@ -1,19 +1,62 @@
 use std::fmt;
 
-use crate::makefile::command_line::CommandLine;
+use eyre::{eyre, Result};
+use regex::Captures;
+
+use super::command_line::CommandLine;
+use super::pattern::r#match;
 
 #[derive(PartialEq, Eq, Clone, Debug)]
 pub struct InferenceRule {
-    /// POSIX calls this ".s1" but that's not useful.
-    pub product: String,
-    /// POSIX calls this ".s2" but that's not useful.
-    pub prereq: String,
+    pub products: Vec<String>,
+    pub prerequisites: Vec<String>,
     pub commands: Vec<CommandLine>,
 }
 
+impl InferenceRule {
+    /// s1 is the product, s2 is the prereq
+    pub fn new_suffix(s1: String, s2: String, commands: Vec<CommandLine>) -> Self {
+        Self {
+            products: vec![format!("%.{}", s1)],
+            prerequisites: vec![format!("%.{}", s2)],
+            commands,
+        }
+    }
+
+    fn first_match<'s, 't: 's>(&'s self, target_name: &'t str) -> Result<Option<Captures<'t>>> {
+        self.products
+            .iter()
+            .map(|pattern| r#match(pattern, target_name))
+            .try_fold(None, |x, y| y.map(|y| x.or(y)))
+    }
+
+    pub fn matches(&self, target_name: &str) -> Result<bool> {
+        self.first_match(target_name).map(|x| x.is_some())
+    }
+
+    pub fn prereqs<'s>(
+        &'s self,
+        target_name: &'s str,
+    ) -> Result<impl Iterator<Item = String> + 's> {
+        let capture = self
+            .first_match(target_name)?
+            .ok_or_else(|| eyre!("asked non-matching inference rule for prerequisites"))?;
+        let percent_expansion = capture.get(1).expect("should've matched the %").as_str();
+        Ok(self
+            .prerequisites
+            .iter()
+            .map(move |p| p.replace('%', percent_expansion)))
+    }
+}
+
 impl fmt::Display for InferenceRule {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        writeln!(f, "{}{}:", &self.prereq, &self.product)?;
+        writeln!(
+            f,
+            "{}: {}",
+            self.products.join(" "),
+            self.prerequisites.join(" ")
+        )?;
         for command in &self.commands {
             writeln!(f, "\t{}", command)?;
         }
diff --git a/src/makefile/input.rs b/src/makefile/input.rs
index 3abdb8b..3a3508f 100644
--- a/src/makefile/input.rs
+++ b/src/makefile/input.rs
@@ -375,19 +375,33 @@ impl<'a, 'parent, R: BufRead> MakefileReader<'a, 'parent, R> {
             return Ok(());
         }
 
-        // we don't know yet if it's a target rule or an inference rule
+        // we don't know yet if it's a target rule or an inference rule (or a GNUish "pattern rule")
         let inference_match = inference_match(&targets, &prerequisites);
+        #[cfg(feature = "full")]
+        let is_pattern = targets.iter().all(|x| x.contains('%'));
 
-        if let Some(inference_match) = inference_match {
+        #[cfg(feature = "full")]
+        if is_pattern {
             let new_rule = InferenceRule {
-                product: inference_match.name("s1").unwrap().as_str().to_owned(),
-                prereq: inference_match.name("s2").unwrap().as_str().to_owned(),
+                products: targets.into_iter().map(|x| x.to_owned()).collect(),
+                prerequisites,
                 commands,
             };
 
+            self.inference_rules.push(new_rule);
+            return Ok(());
+        }
+
+        if let Some(inference_match) = inference_match {
+            let new_rule = InferenceRule::new_suffix(
+                inference_match.name("s1").unwrap().as_str().to_owned(),
+                inference_match.name("s2").unwrap().as_str().to_owned(),
+                commands,
+            );
+
             self.inference_rules.retain(|existing_rule| {
-                (&existing_rule.prereq, &existing_rule.product)
-                    != (&new_rule.prereq, &new_rule.product)
+                (&existing_rule.prerequisites, &existing_rule.products)
+                    != (&new_rule.prerequisites, &new_rule.products)
             });
             self.inference_rules.push(new_rule);
         } else {
diff --git a/src/makefile/mod.rs b/src/makefile/mod.rs
index 3d824b9..225ff55 100644
--- a/src/makefile/mod.rs
+++ b/src/makefile/mod.rs
@@ -2,7 +2,7 @@ use std::cell::{Cell, RefCell};
 use std::collections::HashMap;
 use std::env;
 use std::fmt;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 use std::rc::Rc;
 
 use eyre::{eyre, Result};
@@ -103,7 +103,7 @@ impl<'a> Makefile<'a> {
 
     pub fn get_target(&self, name: &str) -> Result<Rc<RefCell<Target>>> {
         // TODO implement .POSIX
-        let follow_gnu = true;
+        let follow_gnu = cfg!(feature = "full");
 
         let vpath_options = match self.macros.get("VPATH") {
             Some((_, vpath)) if follow_gnu => {
@@ -113,16 +113,16 @@ impl<'a> Makefile<'a> {
             _ => vec![],
         };
 
-        let targets = self.targets.borrow();
         let mut new_target = None;
         let exists_but_infer_anyway = if follow_gnu {
-            targets
+            self.targets
+                .borrow()
                 .get(name)
                 .map_or(false, |target| target.borrow().commands.is_empty())
         } else {
             false
         };
-        if !targets.contains_key(name) || exists_but_infer_anyway {
+        if !self.targets.borrow().contains_key(name) || exists_but_infer_anyway {
             // When no target rule is found to update a target, the inference rules shall
             // be checked. The suffix of the target to be built...
             let suffix = Path::new(name)
@@ -132,39 +132,51 @@ impl<'a> Makefile<'a> {
             // targets. If the .s1 suffix is found in .SUFFIXES...
             if self.special_target_has_prereq(".SUFFIXES", &suffix) || suffix.is_empty() {
                 // the inference rules shall be searched in the order defined...
-                'rules: for rule in self
+                // TODO implement GNUish shortest-stem-first matching
+                let inference_rule_candidates = self
                     .inference_rules
                     .iter()
-                    // for the first .s2.s1 rule...
-                    .filter(|rule| rule.product == suffix)
-                {
+                    .filter(|rule| rule.matches(name).unwrap_or(false));
+                for rule in inference_rule_candidates {
                     // whose prerequisite file ($*.s2) exists.
-                    let prereq_path =
-                        Path::new(name).with_extension(rule.prereq.trim_start_matches('.'));
-                    if let Some(prereq) = std::iter::once(prereq_path.clone())
-                        .chain(
-                            if prereq_path.is_absolute() {
+                    let prereq_paths = rule
+                        .prereqs(name)?
+                        .map(|prereq_path_name| {
+                            if name == prereq_path_name {
+                                // we can't build this based on itself! fuck outta here
+                                return None;
+                            }
+                            if self.get_target(&prereq_path_name).is_ok() {
+                                return Some(prereq_path_name);
+                            }
+                            let prereq_path = PathBuf::from(prereq_path_name);
+                            let prereq_vpath_options = if prereq_path.is_absolute() {
                                 None
                             } else {
                                 Some(vpath_options.iter().map(|vpath| vpath.join(&prereq_path)))
                             }
                             .into_iter()
-                            .flatten(),
-                        )
-                        .find(|prereq| prereq.exists())
-                    {
+                            .flatten();
+                            std::iter::once(prereq_path.clone())
+                                .chain(prereq_vpath_options)
+                                .find(|prereq| prereq.exists())
+                                .map(|path| path.to_string_lossy().to_string())
+                        })
+                        .collect::<Option<Vec<String>>>();
+                    if let Some(prereqs) = prereq_paths {
                         new_target = Some(Target {
                             name: name.into(),
-                            prerequisites: vec![prereq.to_string_lossy().into()],
+                            prerequisites: prereqs,
                             commands: rule.commands.clone(),
                             already_updated: Cell::new(false),
                         });
-                        break 'rules;
+                        break;
                     }
                 }
             }
         }
 
+        let targets = self.targets.borrow();
         if !targets.contains_key(name) && new_target.is_none() {
             // well, inference didn't work. is there a default?
             if let Some(default) = targets.get(".DEFAULT") {
@@ -315,11 +327,11 @@ fn builtin_inference_rules() -> Vec<InferenceRule> {
         {$(.$first:tt$(.$second:tt)?:
             $($cmd:literal)+)+} => {
             vec![$(
-                InferenceRule {
-                    product: prepend_dot!($($second)?).into(),
-                    prereq: concat!(".", stringify!($first)).into(),
-                    commands: vec![$(CommandLine::from($cmd.parse().unwrap())),+],
-                }
+                InferenceRule::new_suffix(
+                    prepend_dot!($($second)?).into(),
+                    concat!(".", stringify!($first)).into(),
+                    vec![$(CommandLine::from($cmd.parse().unwrap())),+],
+                )
             ),+]
         };
     }