Initial sketch of path2 module, starting with WindowsPath.

Author: graydon

src/libcore/path2.rs

@@ -0,0 +1,311 @@
+extern mod std;
+
+struct WindowsPath {
+    host: option<~str>;
+    device: option<~str>;
+    is_absolute: bool;
+    components: ~[~str];
+}
+
+struct PosixPath {
+    is_absolute: bool;
+    components: ~[~str];
+}
+
+trait Path {
+
+    static fn from_str((&str)) -> self;
+    fn to_str() -> ~str;
+
+    fn dirname() -> ~str;
+    fn filename() -> option<~str>;
+    fn filestem() -> option<~str>;
+    fn filetype() -> option<~str>;
+
+    fn with_dirname((&str)) -> self;
+    fn with_filename((&str)) -> self;
+    fn with_filestem((&str)) -> self;
+    fn with_filetype((&str)) -> self;
+
+    fn push_components((&[~str])) -> self;
+    fn pop_component() -> self;
+}
+
+
+impl WindowsPath : Path {
+
+    fn to_str() -> ~str {
+        match self.filename() {
+          none => self.dirname(),
+          some(ref f) =>
+          if (self.components.len() == 1 &&
+              !self.is_absolute &&
+              self.host == none &&
+              self.device == none) {
+            copy *f
+          } else {
+            self.dirname() + "\\" + *f
+          }
+        }
+    }
+
+    static fn from_str(s: &str) -> WindowsPath {
+        let host;
+        let device;
+        let rest;
+
+        match windows::extract_drive_prefix(s) {
+          some((ref d, ref r)) => {
+            host = none;
+            device = some(copy *d);
+            rest = copy *r;
+          }
+          none => {
+            match windows::extract_unc_prefix(s) {
+              some((ref h, ref r)) => {
+                host = some(copy *h);
+                device = none;
+                rest = copy *r;
+              }
+              none => {
+                host = none;
+                device = none;
+                rest = str::from_slice(s);
+              }
+            }
+          }
+        }
+
+        let mut components =
+            str::split_nonempty(rest, |c| windows::is_sep(c as u8));
+        let is_absolute = (rest.len() != 0 && windows::is_sep(rest[0]));
+        return WindowsPath { host: host,
+                             device: device,
+                             is_absolute: is_absolute,
+                            components: components }
+    }
+
+    fn dirname() -> ~str {
+        let mut s = ~"";
+        match self.host {
+          some(h) => { s += "\\\\"; s += h; }
+          none => { }
+        }
+        match self.device {
+          some(d) => { s += d; s += ":"; }
+          none => { }
+        }
+        if self.is_absolute {
+            s += "\\";
+        }
+        let mut d = copy self.components;
+        if d.len() != 0 {
+            vec::pop(d);
+        }
+        s += str::connect(d, "\\");
+        if s.len() == 0 {
+            s = ~".";
+        }
+        return s;
+    }
+
+    fn filename() -> option<~str> {
+        match self.components.len() {
+          0 => none,
+          1 => some(copy self.components[0]),
+          n => some(copy self.components[n - 1])
+        }
+    }
+
+    fn filestem() -> option<~str> {
+        match self.filename() {
+          none => none,
+          some(ref f) => {
+            match str::rfind_char(*f, '.') {
+              some(p) => some(f.slice(0, p)),
+              none => some(copy *f)
+            }
+          }
+        }
+    }
+
+    fn filetype() -> option<~str> {
+        match self.filename() {
+          none => none,
+          some(ref f) => {
+            match str::rfind_char(*f, '.') {
+              some(p) if p+1 < f.len() => some(f.slice(p+1, f.len())),
+              _ => none
+            }
+          }
+        }
+    }
+
+    fn with_dirname(d: &str) -> WindowsPath {
+        let dpath = from_str::<WindowsPath>(d);
+        match self.filename() {
+          some(ref f) => dpath.push_components(~[copy *f]),
+          none => dpath
+        }
+    }
+
+    fn with_filename(f: &str) -> WindowsPath {
+        assert ! str::any(f, |c| windows::is_sep(c as u8));
+        self.dir_path().push_components(~[str::from_slice(f)])
+    }
+
+    fn with_filestem(s: &str) -> WindowsPath {
+        match self.filetype() {
+          none => self.with_filename(s),
+          some(ref t) =>
+          self.with_filename(str::from_slice(s) + "." + *t)
+        }
+    }
+
+    fn with_filetype(t: &str) -> WindowsPath {
+        let t = ~"." + str::from_slice(t);
+        match self.filestem() {
+          none => self.with_filename(t),
+          some(ref s) =>
+          self.with_filename(*s + t)
+        }
+    }
+
+    fn dir_path() -> WindowsPath {
+        if self.components.len() != 0 {
+            self.pop_component()
+        } else {
+            copy self
+        }
+    }
+
+    fn file_path() -> WindowsPath {
+        let cs = match self.filename() {
+          none => ~[],
+          some(ref f) => ~[copy *f]
+        };
+        return WindowsPath { host: none,
+                             device: none,
+                             is_absolute: false,
+                             components: cs }
+    }
+
+    fn push_components(cs: &[~str]) -> WindowsPath {
+        return WindowsPath { components: self.components + cs, ..self }
+    }
+
+    fn pop_component() -> WindowsPath {
+        let mut cs = copy self.components;
+        if cs.len() != 0 {
+            vec::pop(cs);
+        }
+        return WindowsPath { components: cs, ..self }
+    }
+}
+
+// Various windows helpers, and tests for the impl.
+mod windows {
+
+    #[inline(always)]
+    fn is_sep(u: u8) -> bool {
+        u == '/' as u8 || u == '\\' as u8
+    }
+
+    fn extract_unc_prefix(s: &str) -> option<(~str,~str)> {
+        if (s.len() > 1 &&
+            s[0] == '\\' as u8 &&
+            s[1] == '\\' as u8) {
+            let mut i = 2;
+            while i < s.len() {
+                if s[i] == '\\' as u8 {
+                    let pre = s.slice(2, i);
+                    let rest = s.slice(i, s.len());
+                    return some((pre, rest));
+                }
+                i += 1;
+            }
+        }
+        none
+    }
+
+    fn extract_drive_prefix(s: &str) -> option<(~str,~str)> {
+        if (s.len() > 1 &&
+            libc::isalpha(s[0] as libc::c_int) != 0 &&
+            s[1] == ':' as u8) {
+            let rest = if s.len() == 2 { ~"" } else { s.slice(2, s.len()) };
+            return some((s.slice(0,1), rest));
+        }
+        none
+    }
+
+    #[test]
+    fn test_extract_unc_prefixes() {
+        assert extract_unc_prefix("\\\\") == none;
+        assert extract_unc_prefix("\\\\hi") == none;
+        assert extract_unc_prefix("\\\\hi\\") == some((~"hi", ~"\\"));
+        assert extract_unc_prefix("\\\\hi\\there") ==
+            some((~"hi", ~"\\there"));
+        assert extract_unc_prefix("\\\\hi\\there\\friends.txt") ==
+            some((~"hi", ~"\\there\\friends.txt"));
+    }
+
+    #[test]
+    fn test_extract_drive_prefixes() {
+        assert extract_drive_prefix("c") == none;
+        assert extract_drive_prefix("c:") == some((~"c", ~""));
+        assert extract_drive_prefix("d:") == some((~"d", ~""));
+        assert extract_drive_prefix("z:") == some((~"z", ~""));
+        assert extract_drive_prefix("c:\\hi") == some((~"c", ~"\\hi"));
+        assert extract_drive_prefix("d:hi") == some((~"d", ~"hi"));
+        assert extract_drive_prefix("c:hi\\there.txt") ==
+            some((~"c", ~"hi\\there.txt"));
+        assert extract_drive_prefix("c:\\hi\\there.txt") ==
+            some((~"c", ~"\\hi\\there.txt"));
+    }
+
+    #[test]
+    fn test_windows_paths() {
+        fn mk(s: &str) -> WindowsPath { from_str::<WindowsPath>(s) }
+        fn t(wp: &WindowsPath, s: &str) {
+            let ss = wp.to_str();
+            let sss = str::from_slice(s);
+            if (ss != sss) {
+                debug!("got %s", ss);
+                debug!("expected %s", sss);
+                assert ss == sss;
+            }
+        }
+
+        t(&(mk("hi")), "hi");
+        t(&(mk("hi/there")), "hi\\there");
+        t(&(mk("hi/there.txt")), "hi\\there.txt");
+
+        t(&(mk("there.txt")
+            .with_filetype("o")), "there.o");
+
+        t(&(mk("hi/there.txt")
+            .with_filetype("o")), "hi\\there.o");
+
+        t(&(mk("hi/there.txt")
+            .with_filetype("o")
+            .with_dirname("c:\\program files A")),
+          "c:\\program files A\\there.o");
+
+        t(&(mk("hi/there.txt")
+            .with_filetype("o")
+            .with_dirname("c:\\program files B\\")),
+          "c:\\program files B\\there.o");
+
+        t(&(mk("hi/there.txt")
+            .with_filetype("o")
+            .with_dirname("c:\\program files C\\/")),
+            "c:\\program files C\\there.o");
+
+        t(&(mk("c:\\program files (x86)\\rust")
+            .push_components([~"lib", ~"thingy.dll"])
+            .with_filename("librustc.dll")),
+          "c:\\program files (x86)\\rust\\lib\\librustc.dll");
+
+    }
+
+}