Linux support | Fix -n > file size | print last few lines before foll…

…owing

Cargo.toml

@@ -1,7 +1,8 @@
 [package]
 name = "trunk"
-version = "0.1.0"
+version = "0.1.1"
 edition = "2021"
+authors = ["stupendoussuperpowers"]
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
@@ -11,3 +12,4 @@ colored = "2.1.0"
 filesize = "0.2.0"
 notify = { version = "6.1.1" }
 static-str = "0.2.0"
+

README.md

@@ -12,19 +12,25 @@ TODO: ensuring linux support as well.
 
 # Usage
 
-Added feature for "sieving". Will follow for file changes -
+Added feature for "sieving". Will follow for file changes
+
 `trunk -s <filter> /path/to/file`
 
-Usual tail commands are compatible -
+Usual tail commands are compatible
+
 `trunk -n <number of lines> /path/to/file`
+
 `trunk -f /path/to/file`
 
 .
+
 .
+
 .
 
-`trunk -h` -
+`trunk -h`
 
+```
 Usage: trunk.exe [OPTIONS] <FILE>
 
 Arguments:
@@ -36,6 +42,7 @@ Options:
 -n, --num-lines <NUM_LINES> Number of lines from the end to tail [default: 5]
 -h, --help Print help
 -V, --version Print version
+```
 
 # Building
 

src/main.rs

@@ -20,18 +20,26 @@ struct FileSpec {
 
 impl FileSpec {
     fn new(fpath: &'static Path) -> Self {
-        let size: u64 = fpath.size_on_disk().unwrap();
-        Self { fpath, size }
+        let size: u64 = 0;
+        let mut ret = Self { fpath, size };
+        ret.update_size();
+        ret
     }
 
+    // size_on_disk() wasn't returning actual file size for linux.
+    #[cfg(target_os = "linux")]
+    fn update_size(&mut self) {
+        self.size = self.fpath.metadata().unwrap().len();
+    }
+
+    #[cfg(target_os = "windows")]
     fn update_size(&mut self) {
         self.size = self.fpath.size_on_disk().unwrap();
     }
 }
 
 fn main() {
     let mut args = Args::parse();
-    println!("Args: {:#?}", args);
 
     let filepath = to_str(args.file);
     let sieve = to_str(args.sieve);
@@ -45,6 +53,9 @@ fn main() {
 
     let mut fspec = FileSpec::new(path);
 
+    let num = args.num_lines.parse::<i32>().unwrap();
+    read_last_n_lines(&mut fspec, num);
+
     if args.follow {
         let mut watcher = notify::recommended_watcher(move |res| match res {
             Ok(_event) => follow_filter(&mut fspec, sieve),
@@ -54,9 +65,6 @@ fn main() {
 
         watcher.watch(path, RecursiveMode::Recursive).unwrap();
         loop {}
-    } else {
-        let num = args.num_lines.parse::<i32>().unwrap();
-        read_last_n_lines(&mut fspec, num)
     }
 }
 
@@ -68,15 +76,18 @@ fn read_last_n_lines(file: &mut FileSpec, num: i32) {
         .open(file.fpath)
         .unwrap();
 
-    let mut start = 1;
-    while b_ns > 0 {
+    let mut start: u64 = 0;
+
+    // Stop when number of \n are met, or the file is completely read.
+    while b_ns > 0 && start < file.size {
         // Read one byte at a time until we reach the specified number of \n's (b_ns)
+        start = start + 1;
+
         f.seek(SeekFrom::Start(file.size - start)).unwrap();
+
         let mut buf = vec![0; 1];
         f.read_exact(&mut buf).unwrap();
 
-        start = start + 1;
-
         if from_utf8(&buf).unwrap() == "\n".to_string() {
             b_ns -= 1;
         }
@@ -88,11 +99,11 @@ fn read_last_n_lines(file: &mut FileSpec, num: i32) {
     let mut buf_print = Vec::new();
     f.read_to_end(&mut buf_print).unwrap();
 
-    println!("{}", String::from_utf8(buf_print).unwrap());
+    print!("{}", String::from_utf8(buf_print).unwrap());
 }
 
 fn follow_filter(file: &mut FileSpec, filter: &str) {
-    if file.fpath.size_on_disk().unwrap() > file.size {
+    if file.fpath.metadata().unwrap().len() >= file.size {
         // Regular tail -f behaviour so far.
         let mut f = File::options()
             .read(true)