install: Use show! macro for noncritical errors during execution

Drop the previous flags that would tell whether a noncritical error occured
during execution in favor of the `show!` macro from the error submodule.

This allows us to generate regular error types during execution to signify
failures inside the program, but without prematurely aborting program execution
if not needed or specified.

Also make verbose outputs use `print!` and friends instead of `show_error!` to
ensure verbose output is redirected to stdout, not stderr.

src/uu/install/src/install.rs

@@ -63,7 +63,7 @@ enum InstallError {
     MetadataFailed(std::io::Error),
     NoSuchUser(String),
     NoSuchGroup(String),
-    SilentError(),
+    OmittingDirectory(PathBuf),
 }
 
 impl UCustomError for InstallError {
@@ -119,7 +119,7 @@ impl Display for InstallError {
             IE::MetadataFailed(e) => write!(f, "{}", e.to_string()),
             IE::NoSuchUser(user) => write!(f, "no such user: {}", user),
             IE::NoSuchGroup(group) => write!(f, "no such group: {}", group),
-            IE::SilentError() => write!(f, ""),
+            IE::OmittingDirectory(dir) => write!(f, "omitting directory '{}'", dir.display()),
         }
     }
 }
@@ -416,44 +416,46 @@ fn behavior(matches: &ArgMatches) -> UResult<Behavior> {
 /// GNU man pages describe this functionality as creating 'all components of
 /// the specified directories'.
 ///
-/// Returns an integer intended as a program return code.
+/// Returns a Result type with the Err variant containing the error message.
 ///
 fn directory(paths: Vec<String>, b: Behavior) -> UResult<()> {
     if paths.is_empty() {
         Err(InstallError::DirNeedsArg().into())
     } else {
-        let mut all_successful = true;
-
         for path in paths.iter().map(Path::new) {
             // if the path already exist, don't try to create it again
             if !path.exists() {
-                // Differently than the primary functionality (MainFunction::Standard), the directory
-                // functionality should create all ancestors (or components) of a directory regardless
-                // of the presence of the "-D" flag.
-                // NOTE: the GNU "install" sets the expected mode only for the target directory. All
-                // created ancestor directories will have the default mode. Hence it is safe to use
-                // fs::create_dir_all and then only modify the target's dir mode.
-                if let Err(e) = fs::create_dir_all(path) {
-                    show_error!("{}: {}", path.display(), e);
-                    all_successful = false;
+                // Differently than the primary functionality
+                // (MainFunction::Standard), the directory functionality should
+                // create all ancestors (or components) of a directory
+                // regardless of the presence of the "-D" flag.
+                //
+                // NOTE: the GNU "install" sets the expected mode only for the
+                // target directory. All created ancestor directories will have
+                // the default mode. Hence it is safe to use fs::create_dir_all
+                // and then only modify the target's dir mode.
+                if let Err(e) =
+                    fs::create_dir_all(path).map_err_context(|| format!("{}", path.display()))
+                {
+                    show!(e);
                     continue;
                 }
 
                 if b.verbose {
-                    show_error!("creating directory '{}'", path.display());
+                    println!("creating directory '{}'", path.display());
                 }
             }
 
             if mode::chmod(path, b.mode()).is_err() {
-                all_successful = false;
+                // Error messages are printed by the mode::chmod function!
+                uucore::error::set_exit_code(1);
                 continue;
             }
         }
-        if all_successful {
-            Ok(())
-        } else {
-            Err(InstallError::SilentError().into())
-        }
+        // If the exit code was set, or show! has been called at least once
+        // (which sets the exit code as well), function execution will end after
+        // this return.
+        Ok(())
     }
 }
 
@@ -467,7 +469,7 @@ fn is_new_file_path(path: &Path) -> bool {
 
 /// Perform an install, given a list of paths and behavior.
 ///
-/// Returns an integer intended as a program return code.
+/// Returns a Result type with the Err variant containing the error message.
 ///
 fn standard(mut paths: Vec<String>, b: Behavior) -> UResult<()> {
     let target: PathBuf = b
@@ -504,7 +506,7 @@ fn standard(mut paths: Vec<String>, b: Behavior) -> UResult<()> {
 /// Copy some files into a directory.
 ///
 /// Prints verbose information and error messages.
-/// Returns an integer intended as a program return code.
+/// Returns a Result type with the Err variant containing the error message.
 ///
 /// # Parameters
 ///
@@ -515,22 +517,19 @@ fn copy_files_into_dir(files: &[PathBuf], target_dir: &Path, b: &Behavior) -> UR
     if !target_dir.is_dir() {
         return Err(InstallError::TargetDirIsntDir(target_dir.to_path_buf()).into());
     }
-
-    let mut all_successful = true;
     for sourcepath in files.iter() {
         if !sourcepath.exists() {
-            show_error!(
-                "cannot stat '{}': No such file or directory",
-                sourcepath.display()
+            let err = UIoError::new(
+                std::io::ErrorKind::NotFound,
+                format!("cannot stat '{}'", sourcepath.display()),
             );
-
-            all_successful = false;
+            show!(err);
             continue;
         }
 
         if sourcepath.is_dir() {
-            show_error!("omitting directory '{}'", sourcepath.display());
-            all_successful = false;
+            let err = InstallError::OmittingDirectory(sourcepath.to_path_buf());
+            show!(err);
             continue;
         }
 
@@ -538,21 +537,20 @@ fn copy_files_into_dir(files: &[PathBuf], target_dir: &Path, b: &Behavior) -> UR
         let filename = sourcepath.components().last().unwrap();
         targetpath.push(filename);
 
-        if copy(sourcepath, &targetpath, b).is_err() {
-            all_successful = false;
+        if let Err(e) = copy(sourcepath, &targetpath, b) {
+            show!(e);
         }
     }
-    if all_successful {
-        Ok(())
-    } else {
-        Err(InstallError::SilentError().into())
-    }
+    // If the exit code was set, or show! has been called at least once
+    // (which sets the exit code as well), function execution will end after
+    // this return.
+    Ok(())
 }
 
 /// Copy a file to another file.
 ///
 /// Prints verbose information and error messages.
-/// Returns an integer intended as a program return code.
+/// Returns a Result type with the Err variant containing the error message.
 ///
 /// # Parameters
 ///
@@ -565,6 +563,8 @@ fn copy_file_to_file(file: &Path, target: &Path, b: &Behavior) -> UResult<()> {
 
 /// Copy one file to a new location, changing metadata.
 ///
+/// Returns a Result type with the Err variant containing the error message.
+///
 /// # Parameters
 ///
 /// _from_ must exist as a non-directory.
@@ -707,6 +707,7 @@ fn copy(from: &Path, to: &Path, b: &Behavior) -> UResult<()> {
 }
 
 /// Return true if a file is necessary to copy. This is the case when:
+///
 /// - _from_ or _to_ is nonexistent;
 /// - either file has a sticky bit or set[ug]id bit, or the user specified one;
 /// - either file isn't a regular file;