Add support for embedded "{}"

Given

  find . -exec foo{}bar \;

GNU find will replace `{}` by the filename. This commit matches that
behavior.

Note that this is not required by the POSIX spec.

The GNU testsuite doesn't cover this case, so I've added a test in this
repo.

src/find/matchers/exec.rs

@@ -14,7 +14,7 @@ use walkdir::DirEntry;
 use super::{Matcher, MatcherIO};
 
 enum Arg {
-    Filename,
+    FileArg(Vec<OsString>),
     LiteralArg(OsString),
 }
 
@@ -32,9 +32,14 @@ impl SingleExecMatcher {
     ) -> Result<Self, Box<dyn Error>> {
         let transformed_args = args
             .iter()
-            .map(|&a| match a {
-                "{}" => Arg::Filename,
-                _ => Arg::LiteralArg(OsString::from(a)),
+            .map(|&a| {
+                let parts = a.split("{}").collect::<Vec<_>>();
+                if parts.len() == 1 {
+                    // No {} present
+                    Arg::LiteralArg(OsString::from(a))
+                } else {
+                    Arg::FileArg(parts.iter().map(OsString::from).collect())
+                }
             })
             .collect();
 
@@ -60,10 +65,10 @@ impl Matcher for SingleExecMatcher {
         };
 
         for arg in &self.args {
-            command.arg(match *arg {
-                Arg::LiteralArg(ref a) => a.as_os_str(),
-                Arg::Filename => path_to_file.as_os_str(),
-            });
+            match *arg {
+                Arg::LiteralArg(ref a) => command.arg(a.as_os_str()),
+                Arg::FileArg(ref parts) => command.arg(&parts.join(path_to_file.as_os_str())),
+            };
         }
         if self.exec_in_parent_dir {
             match file_info.path().parent() {

tests/exec_unit_tests.rs

@@ -85,6 +85,37 @@ fn matching_executes_code_in_files_directory() {
     );
 }
 
+#[test]
+fn matching_embedded_filename() {
+    let temp_dir = Builder::new()
+        .prefix("matching_embedded_filename")
+        .tempdir()
+        .unwrap();
+    let temp_dir_path = temp_dir.path().to_string_lossy();
+
+    let abbbc = get_dir_entry_for("test_data/simple", "abbbc");
+    let matcher = SingleExecMatcher::new(
+        &path_to_testing_commandline(),
+        &[temp_dir_path.as_ref(), "abc{}x{}yz"],
+        false,
+    )
+    .expect("Failed to create matcher");
+    let deps = FakeDependencies::new();
+    assert!(matcher.matches(&abbbc, &mut deps.new_matcher_io()));
+
+    let mut f = File::open(temp_dir.path().join("1.txt")).expect("Failed to open output file");
+    let mut s = String::new();
+    f.read_to_string(&mut s)
+        .expect("failed to read output file");
+    assert_eq!(
+        s,
+        fix_up_slashes(&format!(
+            "cwd={}\nargs=\nabctest_data/simple/abbbcxtest_data/simple/abbbcyz\n",
+            env::current_dir().unwrap().to_string_lossy()
+        ))
+    );
+}
+
 #[test]
 /// Running "find . -execdir whatever \;" failed with a No such file or directory error.
 /// It's now fixed, and this is a regression test to check that it stays fixed.