From f73d0b2256f2afc05995929c930b2eeab6800ecf Mon Sep 17 00:00:00 2001
From: Melody Horn <melody@boringcactus.com>
Date: Sat, 3 Apr 2021 18:01:04 -0600
Subject: implement GNUish '%'-based inference rules

---
 src/makefile/mod.rs | 62 ++++++++++++++++++++++++++++++++---------------------
 1 file changed, 37 insertions(+), 25 deletions(-)

(limited to 'src/makefile/mod.rs')

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())),+],
+                )
             ),+]
         };
     }
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