feat(picker): add filesystem-aware path value types

Add `FilePath`, `NoFilePath`, `DirPath`, `NoDirPath`, `SymlinkPath`,
`NoSymlinkPath`, `NoPath`, and `RecursiveFiles` wrapper types with
filesystem validation at parse time. Each type implements
`SinglePickable`
and provides standard conversions via `From`, `AsRef`, `Deref`, and
`DerefMut`.

1 files changed, 167 insertions, 0 deletions

diff --git a/arg_picker/src/builtin/pick_paths.rs b/arg_picker/src/builtin/pick_paths.rs
new file mode 100644
index 0000000..8e6c0fd
--- /dev/null
+++ b/arg_picker/src/builtin/pick_paths.rs
@@ -0,0 +1,167 @@
+use std::{
+    fs,
+    path::{Path, PathBuf},
+};
+
+use crate::{
+    PickerArgResult::{self, NotFound, Parsed, Unparsed},
+    SinglePickable,
+    value::{
+        DirPath, FilePath, NoDirPath, NoFilePath, NoPath, NoSymlinkPath, RecursiveFiles,
+        SymlinkPath,
+    },
+};
+
+impl SinglePickable for FilePath {
+    fn pick_single(str: Option<&str>) -> PickerArgResult<Self> {
+        match <PathBuf as SinglePickable>::pick_single(str) {
+            Parsed(path) => {
+                if path.exists() && path.is_file() {
+                    Parsed(FilePath::from(path))
+                } else {
+                    NotFound
+                }
+            }
+            Unparsed => Unparsed,
+            NotFound => NotFound,
+        }
+    }
+}
+
+impl SinglePickable for NoFilePath {
+    fn pick_single(str: Option<&str>) -> PickerArgResult<Self> {
+        match <PathBuf as SinglePickable>::pick_single(str) {
+            Parsed(path) => {
+                if !path.exists() || !path.is_file() {
+                    Parsed(NoFilePath::from(path))
+                } else {
+                    NotFound
+                }
+            }
+            Unparsed => Unparsed,
+            NotFound => NotFound,
+        }
+    }
+}
+
+impl SinglePickable for DirPath {
+    fn pick_single(str: Option<&str>) -> PickerArgResult<Self> {
+        match <PathBuf as SinglePickable>::pick_single(str) {
+            Parsed(path) => {
+                if path.exists() && path.is_dir() {
+                    Parsed(DirPath::from(path))
+                } else {
+                    NotFound
+                }
+            }
+            Unparsed => Unparsed,
+            NotFound => NotFound,
+        }
+    }
+}
+
+impl SinglePickable for NoDirPath {
+    fn pick_single(str: Option<&str>) -> PickerArgResult<Self> {
+        match <PathBuf as SinglePickable>::pick_single(str) {
+            Parsed(path) => {
+                if !path.exists() || !path.is_dir() {
+                    Parsed(NoDirPath::from(path))
+                } else {
+                    NotFound
+                }
+            }
+            Unparsed => Unparsed,
+            NotFound => NotFound,
+        }
+    }
+}
+
+impl SinglePickable for SymlinkPath {
+    fn pick_single(str: Option<&str>) -> PickerArgResult<Self> {
+        match <PathBuf as SinglePickable>::pick_single(str) {
+            Parsed(path) => {
+                if path.exists() && path.is_symlink() {
+                    Parsed(SymlinkPath::from(path))
+                } else {
+                    NotFound
+                }
+            }
+            Unparsed => Unparsed,
+            NotFound => NotFound,
+        }
+    }
+}
+
+impl SinglePickable for NoSymlinkPath {
+    fn pick_single(str: Option<&str>) -> PickerArgResult<Self> {
+        match <PathBuf as SinglePickable>::pick_single(str) {
+            Parsed(path) => {
+                if !path.exists() || !path.is_symlink() {
+                    Parsed(NoSymlinkPath::from(path))
+                } else {
+                    NotFound
+                }
+            }
+            Unparsed => Unparsed,
+            NotFound => NotFound,
+        }
+    }
+}
+
+impl SinglePickable for NoPath {
+    fn pick_single(str: Option<&str>) -> PickerArgResult<Self> {
+        match <PathBuf as SinglePickable>::pick_single(str) {
+            Parsed(path) => {
+                if !path.exists() {
+                    Parsed(NoPath::from(path))
+                } else {
+                    NotFound
+                }
+            }
+            Unparsed => Unparsed,
+            NotFound => NotFound,
+        }
+    }
+}
+
+impl SinglePickable for RecursiveFiles {
+    fn pick_single(str: Option<&str>) -> PickerArgResult<Self> {
+        match <PathBuf as SinglePickable>::pick_single(str) {
+            Parsed(path) => {
+                if !path.exists() {
+                    return NotFound;
+                }
+                if path.is_file() || path.is_symlink() {
+                    return Parsed(RecursiveFiles::from(vec![path]));
+                }
+                let mut entries = Vec::new();
+                if let Ok(dir_entries) = fs::read_dir(&path) {
+                    for entry in dir_entries.flatten() {
+                        let entry_path = entry.path();
+                        if entry_path.is_file() || entry_path.is_symlink() {
+                            entries.push(entry_path);
+                        } else if entry_path.is_dir() {
+                            collect_files(&entry_path, &mut entries);
+                        }
+                    }
+                }
+                Parsed(RecursiveFiles::from(entries))
+            }
+            Unparsed => Unparsed,
+            NotFound => NotFound,
+        }
+    }
+}
+
+fn collect_files(dir: &Path, entries: &mut Vec<PathBuf>) {
+    if let Ok(dir_entries) = fs::read_dir(dir) {
+        for entry in dir_entries.flatten() {
+            let entry_path = entry.path();
+            if entry_path.is_file() || entry_path.is_symlink() {
+                entries.push(entry_path);
+            } else if entry_path.is_dir() {
+                collect_files(&entry_path, entries);
+            }
+        }
+    }
+}