compiler: Track/Report Relative Paths Names

When the user gives relative path names for p4 files, report
those in error messages (etc.). The SourceManager can/does
resolve those to absolute path names.

Signed-off-by: Will Hawkins <hawkinsw@obs.cr>

Sources/Common/SourceCode.swift

@@ -85,7 +85,7 @@ public struct SourceManager {
 
     let fm = FileManager()
     for path in self.paths {
-      let combined = path.pushing(file)
+      let combined = path.pushing(file).lexicallyNormalized()
       if fm.fileExists(atPath: combined.string) {
         return combined
       }
@@ -247,14 +247,24 @@ public struct SourceCode {
 }
 
 func do_preprocess(
-  _ file: URL, _ manager: SourceManager, _ starting: Int = 0
+  _ file: FilePath, _ manager: SourceManager, _ starting: Int = 0
 ) -> Result<(FileSourceLocation, String)> {
   // First (1) match group has the name of the include file.
   let re = /\#include[\s]*<([^\s>]*)>/
 
   do {
     var locations: [FileSourceLocation] = Array()
-    var contents = try String.init(contentsOf: file, encoding: String.defaultCStringEncoding)
+
+    // First, try to find the file.
+    guard let included_path = manager.firstExisting(file) else {
+      return .Error(
+        Error(
+          withMessage:
+            "Could not open \(file) for preprocessing"))
+    }
+
+    var contents = try String.init(
+      contentsOf: URL(filePath: included_path.string), encoding: String.defaultCStringEncoding)
     var changed = true
 
     while changed {
@@ -264,20 +274,9 @@ func do_preprocess(
         let before = contents[..<match.range.lowerBound]
         let after = contents[match.range.upperBound...]
 
-        // Determine whether there is a file with that name in the include path.
-        guard let included_path = manager.firstExisting(FilePath.init("\(match.1)")) else {
-          return .Error(
-            Error(
-              withMessage:
-                "Could not open \(match.1) for inclusion"))
-        }
-
-        // Try to make a url from the configured file.
-        let included_url = URL.init(filePath: included_path.string)
-
         // By calling ourselves recursively, the include being processed will
         // be _completely_ expanded (including any nested includes).
-        switch do_preprocess(included_url, manager, starting + before.count) {
+        switch do_preprocess(FilePath("\(match.1)"), manager, starting + before.count) {
         case .Ok((let location, let expanded)):
           // Recombine what was before and after the include being processed
           // with the expanded text.
@@ -298,7 +297,7 @@ func do_preprocess(
     return .Ok(
       (
         FileSourceLocation(
-          SourceLocation(starting..<(starting + contents.count)), FilePath(file.path()), locations),
+          SourceLocation(starting..<(starting + contents.count)), file, locations),
         contents
       ))
 
@@ -316,22 +315,7 @@ public struct SourceCodePreprocessor {
   }
 
   public func preprocess(_ file: FilePath) -> Result<SourceCode> {
-    // First, decide whether the given file exists at the path the user gave.
-    let fm = FileManager()
-    let file_to_open =
-      if !fm.fileExists(atPath: file.string) {
-        self.manager.firstExisting(file)
-      } else {
-        file
-      }
-
-    guard let file_to_open else {
-      return .Error(Error(withMessage: "Could not open \(file) for preprocessing"))
-    }
-
-    let url = URL.init(filePath: file_to_open.string)
-
-    switch do_preprocess(url, self.manager) {
+    switch do_preprocess(file, self.manager) {
     case .Ok((let location, let contents)):
       return .Ok(SourceCode(contents, self.manager, location))
     case .Error(let e): return .Error(e)