Add multithreaded import parsing

Cargo.lock

@@ -1,6 +1,39 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+[[package]]
+name = "autocfg"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "cfg-if"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "crossbeam-utils"
+version = "0.7.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "autocfg 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "lazy_static"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "markdown-rs"
 version = "0.1.0"
+dependencies = [
+ "crossbeam-utils 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
 
+[metadata]
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+"checksum crossbeam-utils 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)" = "c3c7c73a2d1e9fc0886a08b93e98eb643461230d5f1925e4036204d5f2e261a8"
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Cargo.toml

@@ -7,3 +7,4 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+crossbeam-utils = "0.7.2"

src/elements.rs

@@ -1,3 +1,5 @@
+use std::sync::{Arc, Mutex};
+
 #[derive(Clone, Debug)]
 pub enum Block {
     Section(Section),
@@ -6,6 +8,7 @@ pub enum Block {
     Table(Table),
     CodeBlock(CodeBlock),
     Quote(Quote),
+    Import(Import),
 }
 
 #[derive(Clone, Debug)]
@@ -86,6 +89,17 @@ pub struct Quote {
     pub(crate) text: Vec<Text>,
 }
 
+#[derive(Clone, Debug)]
+pub struct Import {
+    pub(crate) path: String,
+    pub(crate) anchor: Arc<Mutex<ImportAnchor>>,
+}
+
+#[derive(Clone, Debug)]
+pub struct ImportAnchor {
+    pub(crate) document: Option<Document>,
+}
+
 #[derive(Clone, Debug)]
 pub struct InlineMetadata {
     pub(crate) data: String,
@@ -271,4 +285,12 @@ impl Quote {
     }
 }
 
-// TODO: Images, URIs
+impl ImportAnchor {
+    pub fn new() -> Self {
+        Self { document: None }
+    }
+
+    pub fn set_document(&mut self, document: Document) {
+        self.document = Some(document);
+    }
+}

src/main.rs

@@ -4,7 +4,10 @@ use std::time::Instant;
 
 fn main() {
     let start = Instant::now();
-    let mut parser = Parser::new(read_to_string("test/document.md").unwrap());
+    let mut parser = Parser::new(
+        read_to_string("test/document.md").unwrap(),
+        Some("test/".to_string()),
+    );
     let document = parser.parse();
     println!("Total duration: {:?}", start.elapsed());
     write("test/document.ast", format!("{:#?}", document)).unwrap();

src/parser.rs

@@ -1,8 +1,13 @@
 use crate::elements::*;
 use crate::tokens::*;
+use crossbeam_utils::sync::WaitGroup;
 use std::error::Error;
 use std::fmt;
 use std::fmt::{Display, Formatter};
+use std::fs::read_to_string;
+use std::path::Path;
+use std::sync::{Arc, Mutex};
+use std::thread;
 
 macro_rules! parse_option {
     ($option:expr, $index:expr) => {
@@ -35,20 +40,33 @@ pub struct Parser {
     current_char: char,
     section_nesting: u8,
     section_return: Option<u8>,
+    path: Option<String>,
+    paths: Arc<Mutex<Vec<String>>>,
+    wg: WaitGroup,
 }
 
 impl Parser {
-    pub fn new(text: String) -> Self {
+    pub fn new(text: String, path: Option<String>) -> Self {
+        Parser::new_as_child(text, path, Arc::new(Mutex::new(Vec::new())))
+    }
+
+    pub fn new_as_child(
+        text: String,
+        path: Option<String>,
+        paths: Arc<Mutex<Vec<String>>>,
+    ) -> Self {
         let mut text: Vec<char> = text.chars().collect();
         text.append(&mut vec!['\n', ' ', '\n']); // push space and newline of eof. it fixes stuff and I don't know why.
         let current_char = text.get(0).unwrap().clone();
-
         Self {
             index: 0,
             text,
             current_char,
             section_nesting: 0,
             section_return: None,
+            path,
+            paths,
+            wg: WaitGroup::new(),
         }
     }
 
@@ -164,6 +182,54 @@ impl Parser {
         Ok(())
     }
 
+    fn transform_path(&mut self, path: String) -> String {
+        let mut path = path;
+        if let Some(selfpath) = &self.path {
+            let path_info = Path::new(&selfpath);
+            if path_info.is_file() {
+                if let Some(dir) = path_info.parent() {
+                    path = format!("{}/{}", dir.to_str().unwrap(), path);
+                }
+            }
+        }
+        return path;
+    }
+
+    /// starts up a new thread to parse the imported document
+    fn import_document(&mut self, path: String) -> Result<Arc<Mutex<ImportAnchor>>, ParseError> {
+        let mut path = self.transform_path(path);
+        let path_info = Path::new(&path);
+        if !path_info.exists() || !path_info.is_file() {
+            println!("Import of \"{}\" failed: The file doesn't exist.", path);
+            return Err(ParseError::new(self.index));
+        }
+        path = path_info.to_str().unwrap().to_string();
+        {
+            let mut paths = self.paths.lock().unwrap();
+            if paths.iter().find(|item| **item == path) != None {
+                println!("Import of \"{}\" failed: Cyclic reference.", path);
+                return Err(ParseError::new(self.index));
+            }
+            paths.push(path.clone());
+        }
+        let anchor = Arc::new(Mutex::new(ImportAnchor::new()));
+        let anchor_clone = Arc::clone(&anchor);
+        let wg = self.wg.clone();
+        let paths = Arc::clone(&self.paths);
+
+        let _ = thread::spawn(move || {
+            let text = read_to_string(path.clone()).unwrap();
+
+            let mut parser = Parser::new_as_child(text.to_string(), Some(path), paths);
+            let document = parser.parse();
+            anchor_clone.lock().unwrap().set_document(document);
+
+            drop(wg);
+        });
+
+        Ok(anchor)
+    }
+
     /// parses the given text into a document
     pub fn parse(&mut self) -> Document {
         let mut document = Document::new();
@@ -173,6 +239,9 @@ impl Parser {
             }
         }
 
+        let wg = self.wg.clone();
+        self.wg = WaitGroup::new();
+        wg.wait();
         document
     }
 
@@ -197,6 +266,8 @@ impl Parser {
             Block::CodeBlock(code_block)
         } else if let Ok(quote) = self.parse_quote() {
             Block::Quote(quote)
+        } else if let Ok(import) = self.parse_import() {
+            Block::Import(import)
         } else if let Ok(paragraph) = self.parse_paragraph() {
             Block::Paragraph(paragraph)
         } else {
@@ -332,6 +403,33 @@ impl Parser {
         Ok(InlineMetadata { data: text })
     }
 
+    /// parses an import and starts a new task to parse the document of the import
+    fn parse_import(&mut self) -> Result<Import, ParseError> {
+        let start_index = self.index;
+        if !self.check_special(&IMPORT_START)
+            || self.next_char() == None
+            || !self.check_special(&IMPORT_OPEN)
+        {
+            return Err(self.revert_with_error(start_index));
+        }
+        let mut path = String::new();
+        while let Some(character) = self.next_char() {
+            if self.check_linebreak() || self.check_special(&IMPORT_CLOSE) {
+                break;
+            }
+            path.push(character);
+        }
+        if self.check_linebreak() || path.is_empty() {
+            return Err(self.revert_with_error(start_index));
+        }
+
+        if let Ok(anchor) = self.import_document(path.clone()) {
+            Ok(Import { path, anchor })
+        } else {
+            Err(ParseError::new(self.index))
+        }
+    }
+
     /// Parses a paragraph
     fn parse_paragraph(&mut self) -> Result<Paragraph, ParseError> {
         let mut paragraph = Paragraph::new();

src/tokens.rs

@@ -17,6 +17,7 @@ pub(crate) const HASH: char = '#';
 pub(crate) const O: char = 'o';
 pub(crate) const X: char = 'x';
 pub(crate) const GT: char = '>';
+pub(crate) const LT: char = '<';
 pub(crate) const BANG: char = '!';
 
 // aliases
@@ -30,11 +31,21 @@ pub(crate) const DESC_CLOSE: char = L_BRACKET;
 pub(crate) const IMG_START: char = BANG;
 pub(crate) const URL_OPEN: char = R_PARENTH;
 pub(crate) const URL_CLOSE: char = L_PARENTH;
+pub(crate) const IMPORT_START: char = LT;
+pub(crate) const IMPORT_OPEN: char = R_BRACKET;
+pub(crate) const IMPORT_CLOSE: char = L_BRACKET;
 
 // groups
 
-pub(crate) const BLOCK_SPECIAL_CHARS: [char; 6] =
-    [HASH, MINUS, BACKTICK, PIPE, QUOTE_START, META_OPEN];
+pub(crate) const BLOCK_SPECIAL_CHARS: [char; 7] = [
+    HASH,
+    MINUS,
+    BACKTICK,
+    PIPE,
+    QUOTE_START,
+    META_OPEN,
+    IMPORT_START,
+];
 pub(crate) const INLINE_SPECIAL_CHARS: [char; 6] = [LB, ASTERISK, UNDERSCR, TILDE, PIPE, BACKTICK];
 pub(crate) const INLINE_SPECIAL_CHARS_SECOND: [char; 3] = [DESC_OPEN, IMG_START, URL_OPEN];