replace homegrown Error with failure crate

This reduces boilerplate, making it a bit easier for me to split the db stuff
out into its own crate.

src/cmds/check.rs

@@ -31,7 +31,7 @@
 //! Subcommand to check the database and sample file dir for errors.
 
 use db;
-use error::Error;
+use failure::Error;
 use recording;
 use std::fs;
 use uuid::Uuid;
@@ -153,9 +153,7 @@ pub fn run() -> Result<(), Error> {
                 error!("composite id {} has recording_playback row but no recording row", id2);
                 continue;
             },
-            (None, None) => {
-                return Err(Error::new("outer join returned fully empty row".to_owned()));
-            },
+            (None, None) => bail!("outer join returned fully empty row"),
         };
         let row_summary = RecordingSummary{
             flags: row.get_checked(1)?,

src/cmds/config/cameras.rs

@@ -35,7 +35,7 @@ use self::cursive::traits::{Boxable, Identifiable, Finder};
 use self::cursive::views;
 use db;
 use dir;
-use error::Error;
+use failure::Error;
 use std::collections::BTreeMap;
 use std::sync::Arc;
 use stream::{self, Opener, Stream};

src/cmds/config/dirs.rs

@@ -35,7 +35,7 @@ use self::cursive::traits::{Boxable, Identifiable};
 use self::cursive::views;
 use db;
 use dir;
-use error::Error;
+use failure::Error;
 use std::cell::RefCell;
 use std::collections::BTreeMap;
 use std::rc::Rc;

src/cmds/config/mod.rs

@@ -38,7 +38,7 @@ extern crate cursive;
 use self::cursive::Cursive;
 use self::cursive::views;
 use db;
-use error::Error;
+use failure::Error;
 use regex::Regex;
 use std::sync::Arc;
 use std::fmt::Write;

src/cmds/init.rs

@@ -29,7 +29,7 @@
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 use db;
-use error::Error;
+use failure::Error;
 
 static USAGE: &'static str = r#"
 Initializes a database.

src/cmds/mod.rs

@@ -30,7 +30,7 @@
 
 use dir;
 use docopt;
-use error::Error;
+use failure::{Error, Fail};
 use libc;
 use rusqlite;
 use std::path::Path;
@@ -78,10 +78,8 @@ fn open_conn(db_dir: &str, mode: OpenMode) -> Result<(dir::Fd, rusqlite::Connect
     let dir = dir::Fd::open(None, db_dir, mode == OpenMode::Create)?;
     let ro = mode == OpenMode::ReadOnly;
     dir.lock(if ro { libc::LOCK_SH } else { libc::LOCK_EX } | libc::LOCK_NB)
-       .map_err(|e| Error{description: format!("db dir {:?} already in use; can't get {} lock",
-                                               db_dir,
-                                               if ro { "shared" } else { "exclusive" }),
-                          cause: Some(Box::new(e))})?;
+       .map_err(|e| e.context(format!("db dir {:?} already in use; can't get {} lock",
+                                      db_dir, if ro { "shared" } else { "exclusive" })))?;
     let conn = rusqlite::Connection::open_with_flags(
         Path::new(&db_dir).join("db"),
         match mode {

src/cmds/run.rs

@@ -31,7 +31,7 @@
 use clock;
 use db;
 use dir;
-use error::Error;
+use failure::Error;
 use fnv::FnvHashMap;
 use futures::{Future, Stream};
 use std::sync::Arc;

src/cmds/ts.rs

@@ -28,7 +28,7 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-use error::Error;
+use failure::Error;
 use recording;
 
 const USAGE: &'static str = r#"

src/cmds/upgrade/mod.rs

@@ -33,7 +33,7 @@
 /// See `guide/schema.md` for more information.
 
 use db;
-use error::Error;
+use failure::Error;
 use rusqlite;
 
 mod v0_to_v1;
@@ -101,10 +101,10 @@ pub fn run() -> Result<(), Error> {
         let old_ver =
             conn.query_row("select max(id) from version", &[], |row| row.get_checked(0))??;
         if old_ver > db::EXPECTED_VERSION {
-            return Err(Error::new(format!("Database is at version {}, later than expected {}",
-                                          old_ver, db::EXPECTED_VERSION)))?;
+            bail!("Database is at version {}, later than expected {}",
+                  old_ver, db::EXPECTED_VERSION);
         } else if old_ver < 0 {
-            return Err(Error::new(format!("Database is at negative version {}!", old_ver)));
+            bail!("Database is at negative version {}!", old_ver);
         }
         info!("Upgrading database from version {} to version {}...", old_ver, db::EXPECTED_VERSION);
         set_journal_mode(&conn, &args.flag_preset_journal).unwrap();

src/cmds/upgrade/v0_to_v1.rs

@@ -31,7 +31,7 @@
 /// Upgrades a version 0 schema to a version 1 schema.
 
 use db;
-use error::Error;
+use failure::Error;
 use recording;
 use rusqlite;
 use std::collections::HashMap;

src/cmds/upgrade/v1_to_v2.rs

@@ -30,7 +30,7 @@
 
 /// Upgrades a version 1 schema to a version 2 schema.
 
-use error::Error;
+use failure::Error;
 use std::fs;
 use rusqlite;
 use schema::DirMeta;
@@ -45,8 +45,8 @@ pub fn new<'a>(args: &'a super::Args) -> Result<Box<super::Upgrader + 'a>, Error
     let sample_file_path =
         args.flag_sample_file_dir
             .as_ref()
-            .ok_or_else(|| Error::new("--sample-file-dir required when upgrading from \
-                                       schema version 1 to 2.".to_owned()))?;
+            .ok_or_else(|| format_err!("--sample-file-dir required when upgrading from \
+                                        schema version 1 to 2."))?;
     Ok(Box::new(U { sample_file_path, dir_meta: None }))
 }
 
@@ -81,8 +81,7 @@ impl<'a> U<'a> {
             let row = row?;
             let uuid: ::db::FromSqlUuid = row.get_checked(0)?;
             if !files.contains(&uuid.0) {
-                return Err(Error::new(format!("{} is missing from dir {}!",
-                                              uuid.0, self.sample_file_path)));
+                bail!("{} is missing from dir {}!", uuid.0, self.sample_file_path);
             }
         }
         Ok(())
@@ -318,7 +317,7 @@ fn fix_video_sample_entry(tx: &rusqlite::Transaction) -> Result<(), Error> {
 fn rfc6381_codec_from_sample_entry(sample_entry: &[u8]) -> Result<String, Error> {
     if sample_entry.len() < 99 || &sample_entry[4..8] != b"avc1" ||
        &sample_entry[90..94] != b"avcC" {
-        return Err(Error::new("not a valid AVCSampleEntry".to_owned()));
+        bail!("not a valid AVCSampleEntry");
     }
     let profile_idc = sample_entry[103];
     let constraint_flags_byte = sample_entry[104];

src/cmds/upgrade/v2_to_v3.rs

@@ -32,7 +32,7 @@
 
 use db::{self, FromSqlUuid};
 use dir;
-use error::Error;
+use failure::Error;
 use libc;
 use std::io::{self, Write};
 use std::mem;