Refactor context creation to a builder pattern

This mainly refactors context creation to use a builder pattern.  It
also adds a logdir option to this builder patter but doesn't yet use
this.

deltachat-ffi/src/lib.rs

@@ -24,7 +24,7 @@ use num_traits::{FromPrimitive, ToPrimitive};
 
 use deltachat::constants::DC_MSG_ID_LAST_SPECIAL;
 use deltachat::contact::Contact;
-use deltachat::context::Context;
+use deltachat::context::{Context, ContextBuilder};
 use deltachat::dc_tools::{
     as_path, dc_strdup, to_opt_string_lossy, to_string_lossy, OsStrExt, StrExt,
 };
@@ -248,22 +248,15 @@ pub unsafe extern "C" fn dc_open(
     }
     let ffi_context = &*context;
     let rust_cb = move |_ctx: &Context, evt: Event| ffi_context.translate_cb(evt);
-
-    let ctx = if blobdir.is_null() || *blobdir == 0 {
-        Context::new(
-            Box::new(rust_cb),
-            ffi_context.os_name.clone(),
-            as_path(dbfile).to_path_buf(),
-        )
-    } else {
-        Context::with_blobdir(
-            Box::new(rust_cb),
-            ffi_context.os_name.clone(),
-            as_path(dbfile).to_path_buf(),
-            as_path(blobdir).to_path_buf(),
-        )
-    };
-    match ctx {
+    let mut builder = ContextBuilder::new(
+        Box::new(rust_cb),
+        ffi_context.os_name.clone(),
+        as_path(dbfile).to_path_buf(),
+    );
+    if !blobdir.is_null() && *blobdir != 0 {
+        builder = builder.blobdir(as_path(blobdir).to_path_buf());
+    }
+    match builder.create() {
         Ok(ctx) => {
             let mut inner_guard = ffi_context.inner.write().unwrap();
             *inner_guard = Some(ctx);

examples/repl/main.rs

@@ -366,11 +366,12 @@ fn main_0(args: Vec<String>) -> Result<(), failure::Error> {
         println!("Error: Bad arguments, expected [db-name].");
         return Err(format_err!("No db-name specified"));
     }
-    let context = Context::new(
+    let context = ContextBuilder::new(
         Box::new(receive_event),
         "CLI".into(),
         Path::new(&args[1]).to_path_buf(),
-    )?;
+    )
+    .create()?;
 
     println!("Delta Chat Core is awaiting your commands.");
 

examples/simple.rs

@@ -39,8 +39,9 @@ fn main() {
     let dir = tempdir().unwrap();
     let dbfile = dir.path().join("db.sqlite");
     println!("creating database {:?}", dbfile);
-    let ctx =
-        Context::new(Box::new(cb), "FakeOs".into(), dbfile).expect("Failed to create context");
+    let ctx = ContextBuilder::new(Box::new(cb), "FakeOs".into(), dbfile)
+        .create()
+        .expect("Failed to create context");
     let running = Arc::new(RwLock::new(true));
     let info = ctx.get_info();
     let duration = time::Duration::from_millis(4000);

src/context.rs

@@ -94,30 +94,92 @@ pub fn get_info() -> HashMap<&'static str, String> {
     res
 }
 
-impl Context {
-    /// Creates new context.
-    pub fn new(cb: Box<ContextCallback>, os_name: String, dbfile: PathBuf) -> Result<Context> {
-        let mut blob_fname = OsString::new();
-        blob_fname.push(dbfile.file_name().unwrap_or_default());
+/// Builder for [Context].
+///
+/// # Example
+///
+/// ```
+/// use deltachat::context::ContextBuilder;
+/// let dir = tempfile::tempdir().unwrap();
+/// let dbfile = dir.path().join("my-context.db");
+/// let ctx = ContextBuilder::new(Box::new(|_, _| 0), "AppName".into(), dbfile)
+///     .blobdir(dir.path().join("my-context-blobs"))
+///     .logdir(dir.path().join("my-context-logs"))
+///     .create()
+///     .unwrap();
+/// assert_eq!(ctx.get_blobdir(), dir.path().join("my-context-blobs"));
+/// ```
+#[derive(DebugStub)]
+pub struct ContextBuilder {
+    #[debug_stub = "Callback"]
+    cb: Box<ContextCallback>,
+    os_name: String,
+    dbfile: PathBuf,
+    blobdir: PathBuf,
+    logdir: PathBuf,
+}
+
+impl ContextBuilder {
+    pub fn new(cb: Box<ContextCallback>, os_name: String, dbfile: PathBuf) -> Self {
+        let db_fname = OsString::from(dbfile.file_name().unwrap_or(&OsString::from("dc-context")));
+        let mut blob_fname = db_fname.clone();
         blob_fname.push("-blobs");
-        let blobdir = dbfile.with_file_name(blob_fname);
-        if !blobdir.exists() {
-            std::fs::create_dir_all(&blobdir)?;
+        let mut log_fname = db_fname.clone();
+        log_fname.push("-logs");
+        ContextBuilder {
+            cb,
+            os_name,
+            blobdir: dbfile.with_file_name(blob_fname),
+            logdir: dbfile.with_file_name(log_fname),
+            dbfile,
         }
-        Context::with_blobdir(cb, os_name, dbfile, blobdir)
     }
 
-    pub fn with_blobdir(
+    pub fn blobdir(mut self, path: PathBuf) -> Self {
+        self.blobdir = path;
+        self
+    }
+
+    pub fn logdir(mut self, path: PathBuf) -> Self {
+        self.logdir = path;
+        self
+    }
+
+    pub fn create(self) -> Result<Context> {
+        if !self.blobdir.exists() {
+            std::fs::create_dir_all(&self.blobdir)?;
+        }
+        if !self.logdir.exists() {
+            std::fs::create_dir_all(&self.logdir)?;
+        }
+        Context::new(
+            self.cb,
+            self.os_name,
+            self.dbfile,
+            self.blobdir,
+            self.logdir,
+        )
+    }
+}
+
+impl Context {
+    fn new(
         cb: Box<ContextCallback>,
         os_name: String,
         dbfile: PathBuf,
         blobdir: PathBuf,
+        logdir: PathBuf,
     ) -> Result<Context> {
         ensure!(
             blobdir.is_dir(),
             "Blobdir does not exist: {}",
             blobdir.display()
         );
+        ensure!(
+            logdir.is_dir(),
+            "Logdir does not exist: {}",
+            logdir.display()
+        );
         let ctx = Context {
             blobdir,
             dbfile,
@@ -526,7 +588,7 @@ mod tests {
         let tmp = tempfile::tempdir().unwrap();
         let dbfile = tmp.path().join("db.sqlite");
         std::fs::write(&dbfile, b"123").unwrap();
-        let res = Context::new(Box::new(|_, _| 0), "FakeOs".into(), dbfile);
+        let res = ContextBuilder::new(Box::new(|_, _| 0), "FakeOs".into(), dbfile).create();
         assert!(res.is_err());
     }
 
@@ -541,7 +603,9 @@ mod tests {
     fn test_blobdir_exists() {
         let tmp = tempfile::tempdir().unwrap();
         let dbfile = tmp.path().join("db.sqlite");
-        Context::new(Box::new(|_, _| 0), "FakeOS".into(), dbfile).unwrap();
+        ContextBuilder::new(Box::new(|_, _| 0), "FakeOS".into(), dbfile)
+            .create()
+            .unwrap();
         let blobdir = tmp.path().join("db.sqlite-blobs");
         assert!(blobdir.is_dir());
     }
@@ -552,7 +616,7 @@ mod tests {
         let dbfile = tmp.path().join("db.sqlite");
         let blobdir = tmp.path().join("db.sqlite-blobs");
         std::fs::write(&blobdir, b"123").unwrap();
-        let res = Context::new(Box::new(|_, _| 0), "FakeOS".into(), dbfile);
+        let res = ContextBuilder::new(Box::new(|_, _| 0), "FakeOS".into(), dbfile).create();
         assert!(res.is_err());
     }
 
@@ -562,7 +626,9 @@ mod tests {
         let subdir = tmp.path().join("subdir");
         let dbfile = subdir.join("db.sqlite");
         let dbfile2 = dbfile.clone();
-        Context::new(Box::new(|_, _| 0), "FakeOS".into(), dbfile).unwrap();
+        ContextBuilder::new(Box::new(|_, _| 0), "FakeOS".into(), dbfile)
+            .create()
+            .unwrap();
         assert!(subdir.is_dir());
         assert!(dbfile2.is_file());
     }
@@ -572,7 +638,9 @@ mod tests {
         let tmp = tempfile::tempdir().unwrap();
         let dbfile = tmp.path().join("db.sqlite");
         let blobdir = PathBuf::new();
-        let res = Context::with_blobdir(Box::new(|_, _| 0), "FakeOS".into(), dbfile, blobdir);
+        let res = ContextBuilder::new(Box::new(|_, _| 0), "FakeOS".into(), dbfile)
+            .blobdir(blobdir)
+            .create();
         assert!(res.is_err());
     }
 
@@ -581,10 +649,36 @@ mod tests {
         let tmp = tempfile::tempdir().unwrap();
         let dbfile = tmp.path().join("db.sqlite");
         let blobdir = tmp.path().join("blobs");
-        let res = Context::with_blobdir(Box::new(|_, _| 0), "FakeOS".into(), dbfile, blobdir);
+        ContextBuilder::new(Box::new(|_, _| 0), "FakeOS".into(), dbfile)
+            .blobdir(blobdir.clone())
+            .create()
+            .unwrap();
+        assert!(blobdir.is_dir());
+    }
+
+    #[test]
+    fn test_with_empty_logdir() {
+        let tmp = tempfile::tempdir().unwrap();
+        let dbfile = tmp.path().join("db.sqlite");
+        let logdir = PathBuf::new();
+        let res = ContextBuilder::new(Box::new(|_, _| 0), "FakeOS".into(), dbfile)
+            .logdir(logdir)
+            .create();
         assert!(res.is_err());
     }
 
+    #[test]
+    fn test_with_logdir_not_exists() {
+        let tmp = tempfile::tempdir().unwrap();
+        let dbfile = tmp.path().join("db.sqlite");
+        let logdir = tmp.path().join("logs");
+        ContextBuilder::new(Box::new(|_, _| 0), "FakeOS".into(), dbfile)
+            .logdir(logdir.clone())
+            .create()
+            .unwrap();
+        assert!(logdir.is_dir());
+    }
+
     #[test]
     fn no_crashes_on_context_deref() {
         let t = dummy_context();

src/test_utils.rs

@@ -7,7 +7,7 @@ use tempfile::{tempdir, TempDir};
 
 use crate::config::Config;
 use crate::constants::KeyType;
-use crate::context::{Context, ContextCallback};
+use crate::context::{Context, ContextBuilder, ContextCallback};
 use crate::events::Event;
 use crate::key;
 
@@ -33,7 +33,9 @@ pub fn test_context(callback: Option<Box<ContextCallback>>) -> TestContext {
         Some(cb) => cb,
         None => Box::new(|_, _| 0),
     };
-    let ctx = Context::new(cb, "FakeOs".into(), dbfile).unwrap();
+    let ctx = ContextBuilder::new(cb, "FakeOs".into(), dbfile)
+        .create()
+        .unwrap();
     TestContext { ctx: ctx, dir: dir }
 }
 

tests/stress.rs

@@ -219,7 +219,9 @@ struct TestContext {
 fn create_test_context() -> TestContext {
     let dir = tempdir().unwrap();
     let dbfile = dir.path().join("db.sqlite");
-    let ctx = Context::new(Box::new(cb), "FakeOs".into(), dbfile).unwrap();
+    let ctx = ContextBuilder::new(Box::new(cb), "FakeOs".into(), dbfile)
+        .create()
+        .unwrap();
     TestContext { ctx, dir }
 }