Make writetoline not be so dumb

ordered took: Duration { secs: 0, nanos: 15943489 }
reversed took: Duration { secs: 5, nanos: 490028410 }
old ordered took: Duration { secs: 11, nanos: 176841460 }
old reversed took: Duration { secs: 19, nanos: 555249871 }

ofborg/src/tasks/log_message_collector.rs

@@ -7,7 +7,7 @@ use std::fs;
 use std::fs::{OpenOptions, File};
 use std::path::{Component, PathBuf};
 
-use ofborg::writetoline;
+use ofborg::writetoline::LineWriter;
 use ofborg::message::buildlogmsg::BuildLogMsg;
 use ofborg::worker;
 use amqp::protocol::basic::{Deliver, BasicProperties};
@@ -19,7 +19,7 @@ pub struct LogFrom {
 }
 
 pub struct LogMessageCollector {
-    handles: LruCache<LogFrom, File>,
+    handles: LruCache<LogFrom, LineWriter>,
     log_root: PathBuf,
 }
 
@@ -58,15 +58,16 @@ impl LogMessageCollector {
         };
     }
 
-    pub fn handle_for(&mut self, from: &LogFrom) -> Result<&mut File, String> {
+    pub fn handle_for(&mut self, from: &LogFrom) -> Result<&mut LineWriter, String> {
         if self.handles.contains_key(&from) {
             return Ok(self.handles.get_mut(&from).expect(
                 "handles just contained the key",
             ));
         } else {
             let logpath = self.path_for(&from)?;
-            let handle = self.open_log(logpath)?;
+            let fp = self.open_log(logpath)?;
-            self.handles.insert(from.clone(), handle);
+            let writer = LineWriter::new(fp);
+            self.handles.insert(from.clone(), writer);
             if let Some(handle) = self.handles.get_mut(&from) {
                 return Ok(handle);
             } else {
@@ -150,11 +151,7 @@ impl worker::SimpleWorker for LogMessageCollector {
     fn consumer(&mut self, job: &LogMessage) -> worker::Actions {
         let mut handle = self.handle_for(&job.from).unwrap();
 
-        writetoline::write_to_line(
+        handle.write_to_line((job.message.line_number - 1) as usize, &job.message.output);
-            &mut handle,
-            (job.message.line_number - 1) as usize,
-            &job.message.output,
-        );
 
         return vec![worker::Action::Ack];
     }

ofborg/src/writetoline.rs

@@ -5,35 +5,87 @@ use std::io::Seek;
 use std::io::SeekFrom;
 use std::fs::File;
 
-pub fn write_to_line(rw: &mut File, line: usize, data: &str) {
+pub struct LineWriter {
+    file: File,
+    buffer: Vec<String>,
+    last_line: usize,
+}
 
-    rw.seek(SeekFrom::Start(0)).unwrap();
+impl LineWriter {
+    pub fn new(mut rw: File) -> LineWriter {
+        let buf = LineWriter::load_buffer(&mut rw);
+        let len = buf.len();
 
-    let reader = BufReader::new(rw.try_clone().unwrap());
+        let writer = LineWriter {
-    let mut lines: Vec<String> = reader
+            file: rw,
+            buffer: buf,
+            last_line: len,
+        };
+
+        return writer;
+    }
+
+    fn load_buffer(file: &mut File) -> Vec<String> {
+        file.seek(SeekFrom::Start(0)).unwrap();
+
+        let reader = BufReader::new(file.try_clone().unwrap());
+        reader
             .lines()
             .map(|line| match line {
                 Ok(s) => s,
                 Err(e) => format!("UTF-8 Decode err: {:?}", e),
             })
-        .collect();
+            .collect()
-    while lines.len() <= line {
-        lines.push("".to_owned());
     }
 
-    lines.remove(line);
+    pub fn write_to_line(&mut self, line: usize, data: &str) {
-    lines.insert(line, data.to_owned());
+        let buffer_len = self.buffer.len();
 
-    let writeout = lines.join("\n");
+        let original_len = self.buffer.len();
-
+        while self.buffer.len() <= line {
-    rw.set_len(0).unwrap();
+            self.buffer.push("".to_owned());
-    rw.seek(SeekFrom::Start(0)).unwrap();
-
-    let bytes = writeout.as_bytes();
-    rw.write_all(bytes).unwrap();
-    rw.write("\n".as_bytes()).unwrap();
         }
 
+        self.buffer.remove(line);
+        self.buffer.insert(line, data.to_owned());
+
+        if self.last_line > line {
+            // println!("taking the rewrite option");
+            // We're inserting in to the middle of a file, so just
+            // write the entire buffer again
+            self.file.set_len(0).unwrap();
+            self.file.seek(SeekFrom::Start(0)).unwrap();
+            self.file
+                .write_all(self.buffer.join("\n").as_bytes())
+                .unwrap();
+            self.file.write("\n".as_bytes());
+        } else {
+            // println!("taking the append option");
+            // println!("Writing {:?} to line {}", data, line);
+
+            let buffer_start = original_len;
+            let buffer_end = line + 1;
+            let to_write = self.buffer[buffer_start..buffer_end].join("\n");
+            // println!("Full buffer: {:?}", self.buffer);
+            // println!("buffer[{}..{}] = {:?}", buffer_start, buffer_end, to_write);
+            // Inclusive range syntax (ie: ...) is experimental, so
+            // to include the final newline in to the written buffer
+            // we have to use one more than the range we want for the
+            // end
+            // println!("selected buffer: {:?}", to_write);
+            self.file.write(to_write.as_bytes()).unwrap();
+            self.file.write("\n".as_bytes());
+        }
+
+        self.last_line = line;
+    }
+
+    pub fn inner(mut self) -> File {
+        self.file
+    }
+}
+
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -42,6 +94,7 @@ mod tests {
     use std::io::Read;
     use std::fs::OpenOptions;
     use ofborg::test_scratch::TestScratch;
+    use std::time::Instant;
 
     fn testfile(path: &Path) -> File {
         OpenOptions::new()
@@ -69,11 +122,23 @@ mod tests {
         let mut f = testfile(&p.path());
 
         assert_file_content(&mut f, "");
-        write_to_line(&mut f, 0, "hello");
+
+        let mut writer = LineWriter::new(f);
+        writer.write_to_line(0, "hello");
+        f = writer.inner();
+
         assert_file_content(&mut f, "hello\n");
-        write_to_line(&mut f, 1, "world");
+
+        let mut writer = LineWriter::new(f);
+        writer.write_to_line(1, "world");
+        f = writer.inner();
+
         assert_file_content(&mut f, "hello\nworld\n");
-        write_to_line(&mut f, 2, ":)");
+
+        let mut writer = LineWriter::new(f);
+        writer.write_to_line(2, ":)");
+        f = writer.inner();
+
         assert_file_content(&mut f, "hello\nworld\n:)\n");
     }
 
@@ -83,16 +148,31 @@ mod tests {
         let mut f = testfile(&p.path());
 
         assert_file_content(&mut f, "");
-        write_to_line(&mut f, 2, ":)");
-        assert_file_content(&mut f, "\n\n:)\n");
 
-        write_to_line(&mut f, 1, "world");
+        {
-        assert_file_content(&mut f, "\nworld\n:)\n");
+            let mut writer = LineWriter::new(f);
-
+            writer.write_to_line(2, ":)");
-        write_to_line(&mut f, 0, "hello");
+            f = writer.inner();
-        assert_file_content(&mut f, "hello\nworld\n:)\n");
         }
 
+        assert_file_content(&mut f, "\n\n:)\n");
+
+        {
+            let mut writer = LineWriter::new(f);
+            writer.write_to_line(1, "world");
+            f = writer.inner();
+        }
+
+        assert_file_content(&mut f, "\nworld\n:)\n");
+
+        {
+            let mut writer = LineWriter::new(f);
+            writer.write_to_line(0, "hello");
+            f = writer.inner();
+        }
+
+        assert_file_content(&mut f, "hello\nworld\n:)\n");
+    }
 
     #[test]
     fn test_writer_line_unordered_long() {
@@ -100,51 +180,141 @@ mod tests {
         let mut f = testfile(&p.path());
 
         assert_file_content(&mut f, "");
-        write_to_line(
+
-            &mut f,
+        {
+            let mut writer = LineWriter::new(f);
+            writer.write_to_line(
                 2,
                 "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
             );
+            f = writer.inner();
+        }
         assert_file_content(
             &mut f,
             "\n\nAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n",
         );
 
-        write_to_line(
+        {
-            &mut f,
+            let mut writer = LineWriter::new(f);
+            writer.write_to_line(
                 1,
                 "BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB",
             );
+            f = writer.inner();
+        }
         assert_file_content(
             &mut f,
             "\nBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB\nAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n",
         );
 
-        write_to_line(
+        {
-            &mut f,
+            let mut writer = LineWriter::new(f);
+            writer.write_to_line(
                 0,
                 "CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC",
             );
+            f = writer.inner();
+        }
         assert_file_content(
             &mut f,
             "CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC\nBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB\nAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n",
         );
     }
 
-
     #[test]
     fn test_writer_line_unordered_longish() {
         let p = TestScratch::new_file("writetoline-unordered-longish");
         let mut f = testfile(&p.path());
 
         assert_file_content(&mut f, "");
-        write_to_line(&mut f, 2, "hello");
+
+        {
+            let mut writer = LineWriter::new(f);
+            writer.write_to_line(2, "hello");
+            f = writer.inner();
+        }
         assert_file_content(&mut f, "\n\nhello\n");
 
-        write_to_line(&mut f, 1, "mynameis");
+        {
+            let mut writer = LineWriter::new(f);
+            writer.write_to_line(1, "mynameis");
+            f = writer.inner();
+        }
         assert_file_content(&mut f, "\nmynameis\nhello\n");
 
-        write_to_line(&mut f, 0, "graham");
+        {
+            let mut writer = LineWriter::new(f);
+            writer.write_to_line(0, "graham");
+            f = writer.inner();
+        }
+        assert_file_content(&mut f, "graham\nmynameis\nhello\n");
+    }
+
+    #[test]
+    fn test_writer_line_ordered_result() {
+        let p = TestScratch::new_file("writetoline-ordered-result");
+        let mut f = testfile(&p.path());
+
+        let mut writer = LineWriter::new(f);
+        writer.write_to_line(0, "hello");
+        writer.write_to_line(1, "world");
+        writer.write_to_line(2, ":)");
+        f = writer.inner();
+
+        assert_file_content(&mut f, "hello\nworld\n:)\n");
+    }
+
+    #[test]
+    fn test_writer_line_unordered_result() {
+        let p = TestScratch::new_file("writetoline-unordered-result");
+        let mut f = testfile(&p.path());
+
+        let mut writer = LineWriter::new(f);
+        writer.write_to_line(2, ":)");
+        writer.write_to_line(1, "world");
+        writer.write_to_line(0, "hello");
+        f = writer.inner();
+
+        assert_file_content(&mut f, "hello\nworld\n:)\n");
+    }
+
+    #[test]
+    fn test_writer_line_unordered_long_result() {
+        let p = TestScratch::new_file("writetoline-unordered-long-result");
+        let mut f = testfile(&p.path());
+
+        let mut writer = LineWriter::new(f);
+        writer.write_to_line(
+            2,
+            "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
+        );
+        writer.write_to_line(
+            1,
+            "BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB",
+        );
+        writer.write_to_line(
+            0,
+            "CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC",
+        );
+        f = writer.inner();
+
+        assert_file_content(
+            &mut f,
+            "CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC\nBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB\nAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n",
+        );
+    }
+
+    #[test]
+    fn test_writer_line_unordered_longish_result() {
+        let p = TestScratch::new_file("writetoline-unordered-longish-result");
+        let mut f = testfile(&p.path());
+
+        let mut writer = LineWriter::new(f);
+        writer.write_to_line(2, "hello");
+        writer.write_to_line(1, "mynameis");
+        writer.write_to_line(0, "graham");
+        f = writer.inner();
+
         assert_file_content(&mut f, "graham\nmynameis\nhello\n");
     }
 
@@ -154,7 +324,42 @@ mod tests {
         let mut f = testfile(&p.path());
 
         assert_file_content(&mut f, "");
-        write_to_line(&mut f, 5, "hello");
+
+        {
+            let mut writer = LineWriter::new(f);
+            writer.write_to_line(5, "hello");
+            f = writer.inner();
+        }
         assert_file_content(&mut f, "\n\n\n\n\nhello\n");
     }
+
+    #[test]
+    fn bench_lots_of_ordered_lines() {
+        let p = TestScratch::new_file("bench-ordered-lines");
+        let mut f = testfile(&p.path());
+        let mut writer = LineWriter::new(f);
+
+        let timer = Instant::now();
+
+        for i in 0..3000 {
+            writer.write_to_line(i, "This is my line!");
+        }
+
+        println!("ordered took: {:?}", timer.elapsed());
+    }
+
+    #[test]
+    fn bench_lots_of_reversed_lines() {
+        let p = TestScratch::new_file("bench-reversed-lines");
+        let mut f = testfile(&p.path());
+        let mut writer = LineWriter::new(f);
+
+        let timer = Instant::now();
+
+        for i in (0..3000).rev() {
+            writer.write_to_line(i, "This is my line!");
+        }
+
+        println!("reversed took: {:?}", timer.elapsed());
+    }
 }