Add option to remove failures

UserGuide.md

@@ -118,7 +118,10 @@ any changes.
 * `ignore` Reads the `ignore` file and updates the database to flag tracks as
 to be ignored for mixes.
 * `export` Exports tags from database and stores within the audio files.
-
+* `clearfail` If analysis fails for a track then the track path and its modification
+time is stored in the database, so that running analysis again ignores these files.
+This action clears this information, so that an analysis run will attempt to analyse
+these files.
 
 
 Analysing tracks
@@ -146,6 +149,10 @@ is shown.
 As a rough guide, a 2015-era i7 8-core laptop with SSD analyses around 14000
 tracks/hour.
 
+If analysis fails for a track, then the track's path and timestamp are stored
+within the database so that subsquent analysis calls will skip these tracks.
+
+
 Tags
 ----
 When analysing tracks, the analyser will first check for a `BLISS_ANALYSIS` tag
@@ -304,7 +311,7 @@ is accomplished as follows:
 Exporting Analysis
 ==================
 
-If you have analysis results stored within the SQLite database, and not within
+If you have analysis results stored within the database, and not within
 the files themselves, then you can use the `export` action to copy these
 analysis results from the database and into the files.
 
@@ -322,6 +329,29 @@ analysis results from the database and into the files.
 
 
 
+Clearing Failed Tracks
+======================
+
+Any tracks that could not be analysed are stored in the database so that
+subsequent analysis runs ignore such files - unless the files themselves
+have been updated.
+
+You can remove this list of failed tracks, from database, via the
+following command:
+
+
+(Linux / macOS)
+```
+./bliss-analyser clearfail
+```
+
+(Windows)
+```
+.\bliss-analyser.exe clearfail
+```
+
+
+
 Credits
 =======
 

src/db.rs

@@ -239,6 +239,10 @@ impl Db {
         self.remove_old_from_table(mpaths, dry_run, "Failures");
     }
 
+    fn clear_failures(&self) {
+        let _ = self.conn.execute("DELETE FROM Failures;", []);
+    }
+
     pub fn get_failure_timestamp(&self, path: &String) -> i64 {
         let mut ts:i64 = 0;
         let mut db_path = path.to_string();
@@ -553,6 +557,13 @@ pub fn export(db_path: &str, mpaths: &Vec<PathBuf>, max_threads: usize, preserve
     db.close();
 }
 
+pub fn clear_failures(db_path: &str) {
+    let db = Db::new(&String::from(db_path));
+    db.init();
+    db.clear_failures();
+    db.close();
+}
+
 pub fn update_ignore(db_path: &str, ignore_path: &PathBuf) {
     let file = File::open(ignore_path).unwrap();
     let reader = BufReader::new(file);

src/main.rs

@@ -91,7 +91,7 @@ fn main() {
         arg_parse.refer(&mut read_tags).add_option(&["-R", "--readtags"], StoreTrue, "When analysing files, attempt to read results from tags");
         arg_parse.refer(&mut preserve_mod_times).add_option(&["-p", "--preserve"], StoreTrue, "Preserve modification time when writing results to files");
         arg_parse.refer(&mut send_notifs).add_option(&["-N", "--notifs"], StoreTrue, "Periodically send notification messages to LMS");
-        arg_parse.refer(&mut task).add_argument("task", Store, "Task to perform; analyse, tags, ignore, upload, export, stopmixer.");
+        arg_parse.refer(&mut task).add_argument("task", Store, "Task to perform; analyse, tags, ignore, upload, export, clearfail, stopmixer.");
         arg_parse.parse_args_or_exit();
     }
 
@@ -110,7 +110,7 @@ fn main() {
     builder.init();
 
     if task.is_empty() {
-        log::error!("No task specified, please choose from; analyse, tags, ignore, upload, export, stopmixer");
+        log::error!("No task specified, please choose from; analyse, tags, ignore, upload, export, clearfail, stopmixer");
         process::exit(-1);
     }
 
@@ -244,6 +244,8 @@ fn main() {
                 db::update_ignore(&db_path, &ignore_path);
             } else if task.eq_ignore_ascii_case("export") {
                 db::export(&db_path, &music_paths, max_threads, preserve_mod_times);
+            } else if task.eq_ignore_ascii_case("clearfail") {
+                db::clear_failures(&db_path);
             } else {
                 let ignore_path = PathBuf::from(&ignore_file);
                 let modified = analyse::analyse_files(&db_path, &music_paths, dry_run, keep_old, max_num_files, max_threads,