WIP refactor: changing internal text representation to be line-based.

This will make some of the internals a little more complex, but should
simplify things on the balance.

src/buffer/mod.rs

@@ -6,6 +6,7 @@ use self::text_node::{TextNode, TextNodeData};
 
 mod text_block;
 mod text_node;
+mod text_line;
 
 
 /// A text buffer

src/buffer/text_line.rs

@@ -0,0 +1,413 @@
+#![allow(dead_code)]
+
+use std::mem;
+use std::str::Graphemes;
+use string_utils::{grapheme_pos_to_byte_pos, is_line_ending};
+
+
+/// A single line of text
+pub struct TextLine {
+    text: Vec<u8>, // The text data, stored as UTF8
+    ending: LineEnding, // The type of line ending, if any
+}
+
+
+impl TextLine {
+    /// Creates a new empty TextLine
+    pub fn new() -> TextLine {
+        TextLine {
+            text: Vec::new(),
+            ending: LineEnding::None,
+        }
+    }
+    
+    
+    /// Creates a new TextLine from a str.
+    pub fn new_from_str(text: &str) -> TextLine {
+        // Initialize TextLine
+        let mut tl = TextLine {
+            text: Vec::with_capacity(text.len()),
+            ending: LineEnding::None,
+        };
+        
+        // Copy text data, stopping on a line ending if any is found
+        for g in text.graphemes(true) {        
+            match g {
+                //==============
+                // Line endings
+                //==============
+                
+                // CRLF
+                "\u{000D}\u{000A}" => {
+                    tl.ending = LineEnding::CRLF;
+                    break;
+                },
+                
+                // LF
+                "\u{000A}" => {
+                    tl.ending = LineEnding::LF;
+                    break;
+                },
+                
+                // VT
+                "\u{000B}" => {
+                    tl.ending = LineEnding::VT;
+                    break;
+                },
+                
+                // FF
+                "\u{000C}" => {
+                    tl.ending = LineEnding::FF;
+                    break;
+                },
+                
+                // CR
+                "\u{000D}" => {
+                    tl.ending = LineEnding::CR;
+                    break;
+                },
+                
+                // NEL
+                "\u{0085}" => {
+                    tl.ending = LineEnding::NEL;
+                    break;
+                },
+                
+                // LS
+                "\u{2028}" => {
+                    tl.ending = LineEnding::LS;
+                    break;
+                },
+                
+                // PS
+                "\u{2029}" => {
+                    tl.ending = LineEnding::PS;
+                    break;
+                },
+                
+                //==================
+                // Other characters
+                //==================
+                
+                _ => {
+                    for b in g.bytes() {
+                        tl.text.push(b);
+                    }
+                }
+            }
+        }
+        
+        // Done!
+        return tl;
+    }
+    
+    
+    /// Returns an immutable string slice into the text block's memory
+    pub fn as_str<'a>(&'a self) -> &'a str {
+        unsafe {
+            mem::transmute(self.text.as_slice())
+        }
+    }
+    
+    
+    /// Inserts `text` at grapheme index `pos`.
+    /// NOTE: panics if it encounters a line ending in the text.
+    pub fn insert_text(&mut self, text: &str, pos: uint) {
+        // Find insertion position in bytes
+        let byte_pos = grapheme_pos_to_byte_pos(self.as_str(), pos);
+
+        // Grow data size        
+        self.text.grow(text.len(), 0);
+        
+        // Move old bytes forward
+        let mut from = self.text.len() - text.len();
+        let mut to = self.text.len();
+        while from > byte_pos {
+            from -= 1;
+            to -= 1;
+            
+            self.text[to] = self.text[from];
+        }
+        
+        // Copy new bytes in
+        let mut i = byte_pos;
+        for g in text.graphemes(true) {
+            if is_line_ending(g) {
+                panic!("TextLine::insert_text(): line ending in inserted text.");
+            }
+            
+            for b in g.bytes() {
+                self.text[i] = b;
+                i += 1
+            }
+        }
+    }
+    
+    
+    /// Returns an iterator over the graphemes of the line
+    pub fn grapheme_iter<'a>(&'a self) -> TextLineIter<'a> {
+        TextLineIter {
+            graphemes: self.as_str().graphemes(true),
+            ending: self.ending,
+            done: false,
+        }
+    }
+    
+    
+    /// Returns an iterator over the graphemes of the line
+    pub fn grapheme_iter_at_index<'a>(&'a self, index: uint) -> TextLineIter<'a> {
+        let temp: &str = unsafe{mem::transmute(self.text.as_slice())};
+        
+        let mut iter = TextLineIter {
+            graphemes: temp.graphemes(true),
+            ending: self.ending,
+            done: false,
+        };
+        
+        for _ in range(0, index) {
+            iter.next();
+        }
+        
+        return iter;
+    }
+}
+
+
+/// Represents one of the valid Unicode line endings.
+/// Also acts as an index into `LINE_ENDINGS`.
+#[deriving(PartialEq, Copy)]
+pub enum LineEnding {
+    None = 0,  // No line ending
+    CRLF = 1,  // CarriageReturn followed by LineFeed
+    LF = 2,    // U+000A -- LineFeed
+    VT = 3,    // U+000B -- VerticalTab
+    FF = 4,    // U+000C -- FormFeed
+    CR = 5,    // U+000D -- CarriageReturn
+    NEL = 6,   // U+0085 -- NextLine
+    LS = 7,    // U+2028 -- Line Separator
+    PS = 8,    // U+2029 -- ParagraphSeparator
+}
+
+/// An array of string literals corresponding to the possible
+/// unicode line endings.
+pub const LINE_ENDINGS: [&'static str, ..9] = ["",
+                          "\u{000D}\u{000A}",
+                          "\u{000A}",
+                          "\u{000B}",
+                          "\u{000C}",
+                          "\u{000D}",
+                          "\u{0085}",
+                          "\u{2028}",
+                          "\u{2029}"
+];
+
+
+/// An iterator over the graphemes of a TextLine
+pub struct TextLineIter<'a> {
+    graphemes: Graphemes<'a>,
+    ending: LineEnding,
+    done: bool,
+}
+
+impl<'a> Iterator<&'a str> for TextLineIter<'a> {
+    fn next(&mut self) -> Option<&'a str> {
+        if self.done {
+            return None;
+        }
+        else {
+            let g = self.graphemes.next();
+            if let Some(_) = g {
+                return g;
+            }
+            else {
+                self.done = true;
+                
+                if self.ending == LineEnding::None {
+                    return None;
+                }
+                else {
+                    return Some(LINE_ENDINGS[self.ending as uint]);
+                }
+            }
+        }
+    }
+}
+
+
+
+
+//=========================================================================
+// TextLine tests
+//=========================================================================
+
+#[test]
+fn new_text_line() {
+    let tl = TextLine::new();
+    
+    assert!(tl.text.len() == 0);
+    assert!(tl.ending == LineEnding::None);
+}
+
+#[test]
+fn new_text_line_from_str() {
+    let tl = TextLine::new_from_str("Hello!");
+    
+    assert!(tl.text.len() == 6);
+    assert!(tl.text[0] == ('H' as u8));
+    assert!(tl.text[1] == ('e' as u8));
+    assert!(tl.text[2] == ('l' as u8));
+    assert!(tl.text[3] == ('l' as u8));
+    assert!(tl.text[4] == ('o' as u8));
+    assert!(tl.text[5] == ('!' as u8));
+    assert!(tl.ending == LineEnding::None);
+}
+
+#[test]
+fn new_text_line_from_empty_str() {
+    let tl = TextLine::new_from_str("");
+    
+    assert!(tl.text.len() == 0);
+    assert!(tl.ending == LineEnding::None);
+}
+
+#[test]
+fn new_text_line_from_str_with_lf() {
+    let tl = TextLine::new_from_str("Hello!\n");
+    
+    assert!(tl.text.len() == 6);
+    assert!(tl.text[0] == ('H' as u8));
+    assert!(tl.text[1] == ('e' as u8));
+    assert!(tl.text[2] == ('l' as u8));
+    assert!(tl.text[3] == ('l' as u8));
+    assert!(tl.text[4] == ('o' as u8));
+    assert!(tl.text[5] == ('!' as u8));
+    assert!(tl.ending == LineEnding::LF);
+}
+
+#[test]
+fn new_text_line_from_str_with_crlf() {
+    let tl = TextLine::new_from_str("Hello!\r\n");
+    
+    assert!(tl.text.len() == 6);
+    assert!(tl.text[0] == ('H' as u8));
+    assert!(tl.text[1] == ('e' as u8));
+    assert!(tl.text[2] == ('l' as u8));
+    assert!(tl.text[3] == ('l' as u8));
+    assert!(tl.text[4] == ('o' as u8));
+    assert!(tl.text[5] == ('!' as u8));
+    assert!(tl.ending == LineEnding::CRLF);
+}
+
+#[test]
+fn new_text_line_from_str_with_crlf_and_too_long() {
+    let tl = TextLine::new_from_str("Hello!\r\nLa la la la");
+    
+    assert!(tl.text.len() == 6);
+    assert!(tl.text[0] == ('H' as u8));
+    assert!(tl.text[1] == ('e' as u8));
+    assert!(tl.text[2] == ('l' as u8));
+    assert!(tl.text[3] == ('l' as u8));
+    assert!(tl.text[4] == ('o' as u8));
+    assert!(tl.text[5] == ('!' as u8));
+    assert!(tl.ending == LineEnding::CRLF);
+}
+
+#[test]
+fn text_line_insert_text() {
+    let mut tl = TextLine::new_from_str("Hello!\r\n");
+    
+    tl.insert_text(" world", 5);
+    
+    assert!(tl.text.len() == 12);
+    assert!(tl.text[0] == ('H' as u8));
+    assert!(tl.text[1] == ('e' as u8));
+    assert!(tl.text[2] == ('l' as u8));
+    assert!(tl.text[3] == ('l' as u8));
+    assert!(tl.text[4] == ('o' as u8));
+    assert!(tl.text[5] == (' ' as u8));
+    assert!(tl.text[6] == ('w' as u8));
+    assert!(tl.text[7] == ('o' as u8));
+    assert!(tl.text[8] == ('r' as u8));
+    assert!(tl.text[9] == ('l' as u8));
+    assert!(tl.text[10] == ('d' as u8));
+    assert!(tl.text[11] == ('!' as u8));
+    assert!(tl.ending == LineEnding::CRLF);
+}
+
+
+//=========================================================================
+// TextLineIter tests
+//=========================================================================
+
+#[test]
+fn text_line_grapheme_iter() {
+    let tl = TextLine::new_from_str("Hello!");
+    let mut iter = tl.grapheme_iter();
+    
+    assert!(iter.next() == Some("H"));
+    assert!(iter.next() == Some("e"));
+    assert!(iter.next() == Some("l"));
+    assert!(iter.next() == Some("l"));
+    assert!(iter.next() == Some("o"));
+    assert!(iter.next() == Some("!"));
+    assert!(iter.next() == None);
+}
+
+#[test]
+fn text_line_grapheme_iter_with_lf() {
+    let tl = TextLine::new_from_str("Hello!\n");
+    let mut iter = tl.grapheme_iter();
+    
+    assert!(iter.next() == Some("H"));
+    assert!(iter.next() == Some("e"));
+    assert!(iter.next() == Some("l"));
+    assert!(iter.next() == Some("l"));
+    assert!(iter.next() == Some("o"));
+    assert!(iter.next() == Some("!"));
+    assert!(iter.next() == Some("\n"));
+    assert!(iter.next() == None);
+}
+
+#[test]
+fn text_line_grapheme_iter_with_crlf() {
+    let tl = TextLine::new_from_str("Hello!\r\n");
+    let mut iter = tl.grapheme_iter();
+    
+    assert!(iter.next() == Some("H"));
+    assert!(iter.next() == Some("e"));
+    assert!(iter.next() == Some("l"));
+    assert!(iter.next() == Some("l"));
+    assert!(iter.next() == Some("o"));
+    assert!(iter.next() == Some("!"));
+    assert!(iter.next() == Some("\r\n"));
+    assert!(iter.next() == None);
+}
+
+#[test]
+fn text_line_grapheme_iter_at_index() {
+    let tl = TextLine::new_from_str("Hello!");
+    let mut iter = tl.grapheme_iter_at_index(2);
+    
+    assert!(iter.next() == Some("l"));
+    assert!(iter.next() == Some("l"));
+    assert!(iter.next() == Some("o"));
+    assert!(iter.next() == Some("!"));
+    assert!(iter.next() == None);
+}
+
+#[test]
+fn text_line_grapheme_iter_at_index_past_end() {
+    let tl = TextLine::new_from_str("Hello!");
+    let mut iter = tl.grapheme_iter_at_index(10);
+    
+    assert!(iter.next() == None);
+}
+
+#[test]
+fn text_line_grapheme_iter_at_index_at_lf() {
+    let tl = TextLine::new_from_str("Hello!\n");
+    let mut iter = tl.grapheme_iter_at_index(6);
+    
+    assert!(iter.next() == Some("\n"));
+    assert!(iter.next() == None);
+}

src/buffer/text_node.rs

@@ -22,6 +22,7 @@ pub enum IndexOrOffset {
 pub struct TextNode {
     pub data: TextNodeData,
     pub tree_height: uint,
+    
     pub char_count: uint,
     pub newline_count: uint,
 }

src/string_utils.rs

@@ -1,6 +1,21 @@
 #![allow(dead_code)]
 //! Misc helpful utility functions for TextBuffer related stuff.
 
+pub fn is_line_ending(text: &str) -> bool {
+    match text {
+        "\u{000D}\u{000A}"
+        | "\u{000A}"
+        | "\u{000B}"
+        | "\u{000C}"
+        | "\u{000D}"
+        | "\u{0085}"
+        | "\u{2028}"
+        | "\u{2029}" => true,
+        
+        _ => false
+    }
+}
+
 pub fn newline_count(text: &str) -> uint {
     let mut count = 0;
     for c in text.chars() {
@@ -48,4 +63,21 @@ pub fn char_pos_to_byte_pos(text: &str, pos: uint) -> uint {
     }
     
     panic!("char_pos_to_byte_pos(): char position off the end of the string.");
+}
+
+pub fn grapheme_pos_to_byte_pos(text: &str, pos: uint) -> uint {
+    let mut i: uint = 0;
+    
+    for (offset, _) in text.grapheme_indices(true) {
+        if i == pos {
+            return offset;
+        }
+        i += 1;
+    }
+    
+    if i == pos {
+        return text.len();
+    }
+    
+    panic!("grapheme_pos_to_byte_pos(): char position off the end of the string.");
 }

todo.md

@@ -6,4 +6,10 @@
 - File opening by entering path
 - UI that wraps editors, for split view.
 - Unit testing for text block, text node, and text buffer.  They must
-  be reliable!
+  be reliable!
+
+- Change text data structure to store lines explicitly.  Still use a tree
+  structure to hold the lines, but just store the lines themselves as
+  straight vectors for now.  Be mindful to keep the API's clean enough
+  that you can substitute another internal storage approach for lines
+  later on.