Fix problem with MAX_PATH on windows + UnitTest

* Manually implemented windows File Namespace name generation

* added some unit tests

closes scullionw#5

.gitignore

@@ -74,4 +74,9 @@ $RECYCLE.BIN/
 # Windows shortcuts
 *.lnk
 
-# End of https://www.gitignore.io/api/linux,macos,windows
+# End of https://www.gitignore.io/api/linux,macos,windows
+
+# Jetrbrains IDE (Intellij RUST/Clion/Idea)
+.idea/
+
+test-data/

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "dirstat-rs"
-version = "0.3.7"
+version = "0.3.8"
 authors = ["scullionw <[email protected]>"]
 edition = "2018"
 license = "MIT"
@@ -19,8 +19,12 @@ atty = "0.2.14"
 serde = { version = "1.0.131", features = ["derive"] }
 serde_json = "1.0.73"
 
+[dev-dependencies]
+const_format = "0.2.22"
+
 [target.'cfg(windows)'.dependencies]
 winapi-util = "0.1.2"
+path-absolutize = "3.0.12"
 
 [target.'cfg(windows)'.dependencies.winapi]
 version = "0.3.7"
@@ -35,3 +39,4 @@ incremental = false
 bench = false
 path = "src/bin/main.rs"
 name = "ds"
+

src/ffi.rs

@@ -11,7 +11,7 @@ use winapi::um::fileapi::GetCompressedFileSizeW;
 use winapi::um::fileapi::INVALID_FILE_SIZE;
 
 pub fn compressed_size(path: &Path) -> Result<u64, Box<dyn Error>> {
-    let wide: Vec<u16> = path.as_os_str().encode_wide().chain(once(0)).collect();
+    let wide = path_to_u16s(path);
     let mut high: u32 = 0;
 
     // TODO: Deal with max path size
@@ -27,6 +27,54 @@ pub fn compressed_size(path: &Path) -> Result<u64, Box<dyn Error>> {
     Ok(u64::from(high) << 32 | u64::from(low))
 }
 
+/// inspired by [fn maybe_verbatim(path: &Path)](https://github.com/rust-lang/rust/blob/1f4681ad7a132755452c32a987ad0f0d075aa6aa/library/std/src/sys/windows/path.rs#L170)
+/// But function from std is calling winapi GetFullPathNameW in case if path is longer than 248.
+/// We are more optimistic and expect all path being absolute, so no API calls from this function.
+fn path_to_u16s(path: &Path) -> Vec<u16> {
+    // Normally the MAX_PATH is 260 UTF-16 code units (including the NULL).
+    // However, for APIs such as CreateDirectory[1], the limit is 248.
+    //
+    // [1]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createdirectorya#parameters
+    const LEGACY_MAX_PATH: usize = 248;
+    // UTF-16 encoded code points, used in parsing and building UTF-16 paths.
+    // All of these are in the ASCII range so they can be cast directly to `u16`.
+    const SEP: u16 = b'\\' as _;
+    const QUERY: u16 = b'?' as _;
+    const U: u16 = b'U' as _;
+    const N: u16 = b'N' as _;
+    const C: u16 = b'C' as _;
+    // \\?\
+    const VERBATIM_PREFIX: &[u16] = &[SEP, SEP, QUERY, SEP];
+    // \??\
+    const NT_PREFIX: &[u16] = &[SEP, QUERY, QUERY, SEP];
+    // \\?\UNC\
+    const UNC_PREFIX: &[u16] = &[SEP, SEP, QUERY, SEP, U, N, C, SEP];
+    // \\
+    const NETWORK_PREFIX: &[u16] = &[SEP, SEP];
+
+    let wide: Vec<u16> = path.as_os_str().encode_wide().chain(once(0)).collect();
+    // don't need to do anything if path is small enaught.
+    if wide.len() < LEGACY_MAX_PATH {
+        return wide;
+    }
+
+    if wide.starts_with(VERBATIM_PREFIX) || wide.starts_with(NT_PREFIX) {
+        return wide;
+    }
+
+    if wide.starts_with(NETWORK_PREFIX) {
+        // network path from SMB
+        let mut tmp = Vec::from(UNC_PREFIX);
+        tmp.extend(&wide[2..]);
+        return tmp;
+    } else {
+        // if we came here, we aren't using network drive, so just prepend File namespace prefix
+        let mut tmp = Vec::from(VERBATIM_PREFIX);
+        tmp.extend(wide);
+        return tmp;
+    }
+}
+
 fn get_last_error() -> u32 {
     unsafe { GetLastError() }
 }

src/lib.rs

@@ -15,11 +15,25 @@ pub struct DiskItem {
 }
 
 impl DiskItem {
+    /// Analyzes provided path and returns tree structure of analyzed DiskItems
     pub fn from_analyze(
         path: &Path,
         apparent: bool,
         root_dev: u64,
     ) -> Result<Self, Box<dyn Error>> {
+        #[cfg(windows)]
+        {
+            // Solution for windows compressed files requires path to be absolute, see ffi.rs
+            // Basically it would be triggered only on top most invocation,
+            // and afterwards all path would be absolute. We do it here as it is relatively harmless
+            // but this would allow us fo it only once instead of each invocation of ffi::compressed_size
+            if apparent && !path.is_absolute() {
+                use path_absolutize::*;
+                let absolute_dir = path.absolutize()?;
+                return Self::from_analyze(absolute_dir.as_ref(), apparent, root_dev);
+            }
+        }
+
         let name = path
             .file_name()
             .unwrap_or(&OsStr::new("."))
@@ -115,3 +129,6 @@ impl FileInfo {
         }
     }
 }
+
+#[cfg(test)]
+mod tests;

src/tests.rs

@@ -0,0 +1,142 @@
+use crate::{DiskItem, FileInfo};
+// warn: don't remove `as &str` after macro invocation.
+// It breaks type checker in Intellij Rust IDE
+use const_format::concatcp;
+use std::fs::File;
+use std::io::Write;
+use std::panic;
+use std::path::Path;
+
+// be aware that rust runs tests in parallel, so tests should use different dirs
+
+const TEST_DATA_DIR: &str = "./test-data/";
+
+const LONG_PATH_DIR: &str = "long-path/";
+//noinspection SpellCheckingInspection
+const PATH_1: &str = "lll1/llllllll/llllllllllllllll/llllllllllllll/lllllllllllll/oooooo\
+oooooooo/oooooooooooooooo/nnnnnnnnn/nnnnnnnnnn/nnnnnnnn/nnnnnn/gggggggggg/p/a/tttt\
+tttttttttt/ttttttttttt/ttttttttttttttt/ttttttttt/tttthhh/2222222222/22222222222/222222222222/\
+3333333333333/33333333/33333333333/33333333333/333333333/33333333/44444444/44444444444444444/\
+5555555/55555555555/55555555/5555555555/5555555/5555555/555555/555555555/66666666666666666666/\
+77777777/7777777777/7777777777777/77777777777/7777777777/77777777/7777777/77777777/8888888888/\
+99999999/999999/99999999/99999999999/99999999/999999999/9999999999/";
+
+const PATH_1_FULL: &str = concatcp!(TEST_DATA_DIR, LONG_PATH_DIR, PATH_1) as &str;
+//noinspection SpellCheckingInspection
+const PATH_2: &str = "lll2/llllllll/llllllllllllllll/llllllllllllll/lllllllllllll/oooooo\
+oooooooo/oooooooooooooooo/nnnnnnnnn/nnnnnnnnnn/nnnnnnnn/nnnnnn/gggggggggg/p/a/tttt\
+tttttttttt/ttttttttttt/ttttttttttttttt/ttttttttt/tttthhh/2222222222/22222222222/222222222222/\
+3333333333333/33333333/33333333333/33333333333/333333333/33333333/44444444/44444444444444444/\
+5555555/55555555555/55555555/5555555555/5555555/5555555/555555/555555555/66666666666666666666/\
+77777777/7777777777/7777777777777/77777777777/7777777777/77777777/7777777/77777777/8888888888/\
+99999999/999999/99999999/99999999999/99999999/999999999/9999999999/";
+
+const PATH_2_FULL: &str = concatcp!(TEST_DATA_DIR, LONG_PATH_DIR, PATH_2) as &str;
+
+#[test]
+fn test_max_path() {
+    // do not rename it into `_` it would cause immediate destrucion after creation
+    let _guard = CleanUpGuard {
+        path: concatcp!(TEST_DATA_DIR, LONG_PATH_DIR) as &str,
+    };
+
+    // Given
+    create_dir(PATH_1_FULL);
+    create_dir(PATH_2_FULL);
+    create_file(&concatcp!(PATH_1_FULL, "file.bin") as &str, 4096);
+    create_file(&concatcp!(PATH_2_FULL, "file.bin") as &str, 8192);
+
+    // When
+    let test_path = Path::new(concatcp!(TEST_DATA_DIR, LONG_PATH_DIR) as &str);
+    let result = FileInfo::from_path(test_path, true);
+
+    // Then
+    if let Result::Ok(FileInfo::Directory { volume_id }) = result {
+        let result = DiskItem::from_analyze(test_path, true, volume_id);
+        let result = result.expect("Must collect data");
+        assert_eq!(result.disk_size, 4096 + 8192);
+        let children = result.children.unwrap();
+        assert_eq!(children.len(), 2);
+        assert_eq!(children[0].disk_size, 8192);
+        assert_eq!(children[1].disk_size, 4096);
+    } else {
+        panic!("Can not get file info");
+    }
+}
+
+#[test]
+#[cfg(unix)] // It gives inconsistent results on windows
+fn test_file_size() {
+    const DIR: &str = concatcp!(TEST_DATA_DIR, "test_file_size/") as &str;
+    // do not rename it into `_` it would cause immediate destrucion after creation
+    let _guard = CleanUpGuard { path: DIR };
+
+    // Given
+    // Such sizes is selected to be close to filesystem sector size, and to be maximally universal
+    // event for FS-es with sector as bif as 8KiB
+    create_file(&concatcp!(DIR, "foo/file.bin") as &str, 8192);
+    create_file(&concatcp!(DIR, "bar/file.bin") as &str, 8192 - 5);
+
+    // When calculating with apparent size
+    let test_path = Path::new(DIR);
+    let result = FileInfo::from_path(test_path, true);
+
+    // Then
+    if let Result::Ok(FileInfo::Directory { volume_id }) = result {
+        let result = DiskItem::from_analyze(test_path, true, volume_id);
+        let result = result.expect("Must collect data");
+        assert_eq!(result.disk_size, 8192 + 8192);
+        let children = result.children.unwrap();
+        assert_eq!(children.len(), 2);
+        // Both dirs should be rounded to sector size
+        assert_eq!(children[0].disk_size, 8192);
+        assert_eq!(children[1].disk_size, 8192);
+    } else {
+        panic!("Can not get file info");
+    }
+
+    // When calculating withOUT apparent size
+    let result = FileInfo::from_path(test_path, false);
+
+    // Then
+    if let Result::Ok(FileInfo::Directory { volume_id }) = result {
+        let result = DiskItem::from_analyze(test_path, false, volume_id);
+        let result = result.expect("Must collect data");
+        assert_eq!(result.disk_size, 8192 + 8192 - 5);
+        let children = result.children.unwrap();
+        assert_eq!(children.len(), 2);
+        // Both dirs should be rounded to sector size
+        assert_eq!(children[0].disk_size, 8192);
+        assert_eq!(children[1].disk_size, 8192 - 5);
+    } else {
+        panic!("Can not get file info");
+    }
+}
+
+// Helper functions and cleanup code goes next
+
+fn create_dir(dir_path: &str) {
+    std::fs::create_dir_all(dir_path).unwrap();
+}
+
+fn create_file(file_path: &str, size: usize) {
+    let content = vec![0u8; size];
+    let file_path = Path::new(file_path);
+    // ensure parent
+    std::fs::create_dir_all(file_path.parent().unwrap()).unwrap();
+
+    let mut file = File::create(file_path).unwrap();
+    file.write(&content).unwrap();
+}
+
+/// Used to clean up test folder after test runs.
+struct CleanUpGuard {
+    path: &'static str,
+}
+
+impl Drop for CleanUpGuard {
+    fn drop(&mut self) {
+        // Teardown
+        std::fs::remove_dir_all(Path::new(self.path)).unwrap();
+    }
+}