Render pages from cache

src/cache.rs

@@ -87,4 +87,44 @@ impl Cache {
         None
     }
 
+    pub fn find_page(&self, name: &str) -> Option<PathBuf> {
+        // Build page file name
+        let page_filename = format!("{}.md", name);
+
+        // Get platform dir
+        let cache_dir = match self.get_cache_dir() {
+            Ok(dir) => dir,
+            Err(_) => return None,
+        };
+        let platforms_dir = cache_dir.join("tldr-master").join("pages");
+
+        // Determine platform
+        let platform = if cfg!(target_os = "linux") {
+            Some("linux")
+        } else if cfg!(target_os = "macos") {
+            Some("osx")
+        } else {
+            None // TODO: Does rust support Sun OS?
+        };
+
+        // Search for the page in the platform specific directory
+        if let Some(pf) = platform {
+            let path = platforms_dir.join(&pf).join(&page_filename);
+            if path.exists() && path.is_file() {
+                return Some(path);
+            }
+        }
+
+        // If platform is not supported or if platform specific page does not exist,
+        // look up the page in the "common" directory.
+        let path = platforms_dir.join("common").join(&page_filename);
+
+        // Return it if it exists, otherwise give up and return `None`
+        if path.exists() && path.is_file() {
+            Some(path)
+        } else {
+            None
+        }
+    }
+
 }

src/main.rs

@@ -12,6 +12,7 @@ extern crate time;
 
 use std::io::BufReader;
 use std::fs::File;
+use std::path::{Path, PathBuf};
 use std::process;
 
 use docopt::Docopt;
@@ -77,13 +78,19 @@ struct Args {
 }
 
 
-/// Open file, return a `BufRead` instance
-fn get_file_reader(filepath: &str) -> Result<BufReader<File>, String> {
+/// Print page by path
+fn print_page(path: &Path) -> Result<(), String> {
+    // Open file
     let file = try!(
-        File::open(filepath)
-            .map_err(|msg| format!("Could not open file: {}", msg))
+        File::open(path).map_err(|msg| format!("Could not open file: {}", msg))
     );
-    Ok(BufReader::new(file))
+    let reader = BufReader::new(file);
+
+    // Create tokenizer and print output
+    let mut tokenizer = Tokenizer::new(reader);
+    print_lines(&mut tokenizer);
+
+    Ok(())
 }
 
 
@@ -134,17 +141,13 @@ fn main() {
 
     // Render local file and exit
     if let Some(file) = args.flag_render {
-        // Open file
-        let reader = get_file_reader(&file).unwrap_or_else(|msg| {
+        let path = PathBuf::from(file);
+        if let Err(msg) = print_page(&path) {
             println!("{}", msg);
             process::exit(1);
-        });
-
-        // Create tokenizer and print output
-        let mut tokenizer = Tokenizer::new(reader);
-        print_lines(&mut tokenizer);
-
-        process::exit(0);
+        } else {
+            process::exit(0);
+        };
     }
 
     // List cached commands and exit
@@ -166,7 +169,7 @@ fn main() {
             match cache.last_update() {
                 Some(ago) if ago > MAX_CACHE_AGE => {
                     println!("Cache wasn't updated in {} days.", MAX_CACHE_AGE / 24 / 3600);
-                    println!("You should probably run `tldr --update` soon."); 
+                    println!("You should probably run `tldr --update` soon.");
                 },
                 None => {
                     println!("Cache not found. Please run `tldr --update`.");
@@ -177,8 +180,19 @@ fn main() {
         }
 
         // Search for command in cache
-        println!("Page rendering from cache not yet implemented.");
-        process::exit(1);
+        if let Some(path) = cache.find_page(&command) {
+            if let Err(msg) = print_page(&path) {
+                println!("{}", msg);
+                process::exit(1);
+            } else {
+                process::exit(0);
+            }
+        } else {
+            println!("Page {} not found in cache", &command);
+            println!("Try updating with `tldr --update`, or submit a pull request to:");
+            println!("https://github.com/tldr-pages/tldr");
+            process::exit(1);
+        }
     }
 
     // Some flags can be run without a command.