Create context objects.

  - Context objects can be used to tweak the library configuration.
    Currently, a home and lib directory can be set.  Reasonable
    defaults are provided.

  - Add ffi functions.

1 files changed, 47 insertions, 1 deletions

diff --git a/src/ffi.rs b/src/ffi.rs
index 3a7b1c66..55911b45 100644
--- a/src/ffi.rs
+++ b/src/ffi.rs
@@ -1,10 +1,56 @@
 extern crate libc;
-use self::libc::{uint8_t, size_t};
+use self::libc::{uint8_t, c_char, size_t};
 
+use std::ffi::CStr;
 use std::ptr;
 use std::slice;
+use std::str;
+
 use keys::TPK;
 use openpgp;
+use super::Context;
+
+/// Create a context object.
+///
+/// If `home` is not `NULL`, it is used as directory containing shared
+/// state and rendezvous nodes.  If `lib` is not `NULL`, it is used as
+/// directory containing backend servers.  If either argument is
+/// `NULL`, a reasonable default is used.
+///
+/// Returns `NULL` on errors.
+#[no_mangle]
+pub extern "system" fn sq_context_new(home: *const c_char,
+                                      lib: *const c_char) -> *mut Context {
+    let home = unsafe {
+        if home.is_null() { None } else { Some(CStr::from_ptr(home)) }
+    };
+    let lib = unsafe {
+        if lib.is_null() { None } else { Some(CStr::from_ptr(lib)) }
+    };
+
+    let mut pre = Context::new();
+
+    if let Some(home) = home {
+        pre = pre.home(home.to_string_lossy().as_ref());
+    }
+    if let Some(lib) = lib {
+        pre = pre.lib(lib.to_string_lossy().as_ref());
+    }
+
+    if let Ok(context) = pre.finalize() {
+        Box::into_raw(Box::new(context))
+    } else {
+        ptr::null_mut()
+    }
+}
+
+/// Free a context.
+#[no_mangle]
+pub extern "system" fn sq_context_free(context: *mut Context) {
+    unsafe {
+        drop(Box::from_raw(context));
+    }
+}
 
 #[no_mangle]
 pub extern "system" fn sq_tpk_from_bytes(b: *const uint8_t, len: size_t) -> *mut TPK {