Add 'domain' to the context.

  - The domain uniquely identifies the application.  It should be a
    property of the context.

3 files changed, 34 insertions, 7 deletions

diff --git a/src/ffi.rs b/src/ffi.rs
index 55911b45..303a0380 100644
--- a/src/ffi.rs
+++ b/src/ffi.rs
@@ -19,8 +19,12 @@ use super::Context;
 ///
 /// Returns `NULL` on errors.
 #[no_mangle]
-pub extern "system" fn sq_context_new(home: *const c_char,
+pub extern "system" fn sq_context_new(domain: *const c_char,
+                                      home: *const c_char,
                                       lib: *const c_char) -> *mut Context {
+    let domain = unsafe {
+        if domain.is_null() { None } else { Some(CStr::from_ptr(domain)) }
+    };
     let home = unsafe {
         if home.is_null() { None } else { Some(CStr::from_ptr(home)) }
     };
@@ -28,7 +32,11 @@ pub extern "system" fn sq_context_new(home: *const c_char,
         if lib.is_null() { None } else { Some(CStr::from_ptr(lib)) }
     };
 
-    let mut pre = Context::new();
+    if domain.is_none() {
+        return ptr::null_mut();
+    }
+
+    let mut pre = Context::new(&domain.unwrap().to_string_lossy());
 
     if let Some(home) = home {
         pre = pre.home(home.to_string_lossy().as_ref());
diff --git a/src/lib.rs b/src/lib.rs
index 7f737aad..ac8afc4e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -23,7 +23,14 @@ use std::io;
 use std::path::{Path, PathBuf};
 
 /// A `&Context` is required for many operations.
+///
+/// # Example
+///
+/// ```
+/// let c = Context::new("org.example.webmail").finalize().unwrap();
+/// ```
 pub struct Context {
+    domain: String,
     home: PathBuf,
     lib: PathBuf,
 }
@@ -34,17 +41,28 @@ fn prefix() -> PathBuf {
 }
 
 impl Context {
-    /// Create a `Pre(Context)` with reasonable defaults.  `Pre(Context)`s
-    /// can be modified, and have to be finalized in order to turn
-    /// them into a Context.
-    pub fn new() -> Pre {
+    /// Creates a `Pre(Context)` with reasonable defaults.
+    ///
+    /// `domain` should uniquely identify your application, it is
+    /// strongly suggested to use a reversed fully qualified domain
+    /// name that is associated with your application.
+    ///
+    /// `Pre(Context)`s can be modified, and have to be finalized in
+    /// order to turn them into a Context.
+    pub fn new(domain: &str) -> Pre {
         Pre(Context {
+            domain: String::from(domain),
             home: env::home_dir().unwrap_or(env::temp_dir())
                 .join(".sequoia"),
             lib: prefix().join("lib").join("sequoia"),
         })
     }
 
+    /// Return the directory containing backend servers.
+    pub fn domain(&self) -> &str {
+        &self.domain
+    }
+
     /// Return the directory containing shared state and rendezvous
     /// nodes.
     pub fn home(&self) -> &Path {
diff --git a/src/sequoia.h b/src/sequoia.h
index 7b3f9cf2..4d43d99c 100644
--- a/src/sequoia.h
+++ b/src/sequoia.h
@@ -3,7 +3,8 @@
 
 struct sq_context;
 
-struct sq_context *sq_context_new(const char *home, const char *lib);
+struct sq_context *sq_context_new(const char *domain, const char *home,
+				  const char *lib);
 void sq_context_free(struct sq_context *context);
 
 struct sq_tpk;