ports/cef: Use the CEF translator tool to generate the full set of CEF

bindings.

This replaces hand-implemented CEF bindings with proper Rust wrappers
automatically generated from the C++ headers. This means that, whenever
CEF's C++ headers change, we can easily generate both the appropriate C
API and the appropriate Rust API. It eliminates much of the hand-written
unsafe code within the CEF port, because the CEF translator tool now
knows how to generate Rust smart pointer wrappers for each class that
corrently perform reference counting.

Additionally, this commit adds utility macros (located in `macros.rs`)
that make it easier to correctly expose Rust objects as CEF objects.
They handle the marshaling of objects between Rust and CEF properly.
The net result of this is that you can write mostly-natural-looking Rust
in the CEF port and interact with it with a natural-looking C++ API on
the embedding side.

This setup relies on the branch of CEF located here:

    https://github.com/pcwalton/chromium-embedded-framework

To regenerate, follow the instructions in `ports/cef/README.md`. For
convenience, and because I don't anticipate the API to change much, I
have vendored in all of the appropriate interfaces.

ports/cef/interfaces/cef_dialog_handler.rs

@@ -0,0 +1,374 @@
+// Copyright (c) 2014 Marshall A. Greenblatt. All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//    * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//    * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//    * Neither the name of Google Inc. nor the name Chromium Embedded
+// Framework nor the names of its contributors may be used to endorse
+// or promote products derived from this software without specific prior
+// written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// ---------------------------------------------------------------------------
+//
+// This file was generated by the CEF translator tool and should not be edited
+// by hand. See the translator.README.txt file in the tools directory for
+// more information.
+//
+
+#![allow(non_snake_case, unused_imports)]
+
+use eutil;
+use interfaces;
+use types;
+use wrappers::CefWrap;
+
+use libc;
+use std::collections::HashMap;
+use std::ptr;
+
+//
+// Callback structure for asynchronous continuation of file dialog requests.
+//
+#[repr(C)]
+pub struct _cef_file_dialog_callback_t {
+  //
+  // Base structure.
+  //
+  pub base: types::cef_base_t,
+
+  //
+  // Continue the file selection with the specified |file_paths|. This may be a
+  // single value or a list of values depending on the dialog mode. An NULL
+  // value is treated the same as calling cancel().
+  //
+  pub cont: Option<extern "C" fn(this: *mut cef_file_dialog_callback_t,
+      file_paths: types::cef_string_list_t) -> ()>,
+
+  //
+  // Cancel the file selection.
+  //
+  pub cancel: Option<extern "C" fn(this: *mut cef_file_dialog_callback_t) -> (
+      )>,
+
+  //
+  // The reference count. This will only be present for Rust instances!
+  //
+  ref_count: uint,
+
+  //
+  // Extra data. This will only be present for Rust instances!
+  //
+  pub extra: u8,
+} 
+
+pub type cef_file_dialog_callback_t = _cef_file_dialog_callback_t;
+
+
+//
+// Callback structure for asynchronous continuation of file dialog requests.
+//
+pub struct CefFileDialogCallback {
+  c_object: *mut cef_file_dialog_callback_t,
+}
+
+impl Clone for CefFileDialogCallback {
+  fn clone(&self) -> CefFileDialogCallback{
+    unsafe {
+      if !self.c_object.is_null() {
+        ((*self.c_object).base.add_ref.unwrap())(&mut (*self.c_object).base);
+      }
+      CefFileDialogCallback {
+        c_object: self.c_object,
+      }
+    }
+  }
+}
+
+impl Drop for CefFileDialogCallback {
+  fn drop(&mut self) {
+    unsafe {
+      if !self.c_object.is_null() {
+        ((*self.c_object).base.release.unwrap())(&mut (*self.c_object).base);
+      }
+    }
+  }
+}
+
+impl CefFileDialogCallback {
+  pub unsafe fn from_c_object(c_object: *mut cef_file_dialog_callback_t) -> CefFileDialogCallback {
+    CefFileDialogCallback {
+      c_object: c_object,
+    }
+  }
+
+  pub unsafe fn from_c_object_addref(c_object: *mut cef_file_dialog_callback_t) -> CefFileDialogCallback {
+    if !c_object.is_null() {
+      ((*c_object).base.add_ref.unwrap())(&mut (*c_object).base);
+    }
+    CefFileDialogCallback {
+      c_object: c_object,
+    }
+  }
+
+  pub fn c_object(&self) -> *mut cef_file_dialog_callback_t {
+    self.c_object
+  }
+
+  pub fn c_object_addrefed(&self) -> *mut cef_file_dialog_callback_t {
+    unsafe {
+      if !self.c_object.is_null() {
+        eutil::add_ref(self.c_object as *mut types::cef_base_t);
+      }
+      self.c_object
+    }
+  }
+
+  pub fn is_null_cef_object(&self) -> bool {
+    self.c_object.is_null()
+  }
+  pub fn is_not_null_cef_object(&self) -> bool {
+    !self.c_object.is_null()
+  }
+
+  //
+  // Continue the file selection with the specified |file_paths|. This may be a
+  // single value or a list of values depending on the dialog mode. An NULL
+  // value is treated the same as calling cancel().
+  //
+  pub fn cont(&self, file_paths: Vec<String>) -> () {
+    if self.c_object.is_null() {
+      panic!("called a CEF method on a null object")
+    }
+    unsafe {
+      CefWrap::to_rust(
+        ((*self.c_object).cont.unwrap())(
+          self.c_object,
+          CefWrap::to_c(file_paths)))
+    }
+  }
+
+  //
+  // Cancel the file selection.
+  //
+  pub fn cancel(&self) -> () {
+    if self.c_object.is_null() {
+      panic!("called a CEF method on a null object")
+    }
+    unsafe {
+      CefWrap::to_rust(
+        ((*self.c_object).cancel.unwrap())(
+          self.c_object))
+    }
+  }
+} 
+
+impl CefWrap<*mut cef_file_dialog_callback_t> for CefFileDialogCallback {
+  fn to_c(rust_object: CefFileDialogCallback) -> *mut cef_file_dialog_callback_t {
+    rust_object.c_object_addrefed()
+  }
+  unsafe fn to_rust(c_object: *mut cef_file_dialog_callback_t) -> CefFileDialogCallback {
+    CefFileDialogCallback::from_c_object_addref(c_object)
+  }
+}
+impl CefWrap<*mut cef_file_dialog_callback_t> for Option<CefFileDialogCallback> {
+  fn to_c(rust_object: Option<CefFileDialogCallback>) -> *mut cef_file_dialog_callback_t {
+    match rust_object {
+      None => ptr::null_mut(),
+      Some(rust_object) => rust_object.c_object_addrefed(),
+    }
+  }
+  unsafe fn to_rust(c_object: *mut cef_file_dialog_callback_t) -> Option<CefFileDialogCallback> {
+    if c_object.is_null() {
+      None
+    } else {
+      Some(CefFileDialogCallback::from_c_object_addref(c_object))
+    }
+  }
+}
+
+
+//
+// Implement this structure to handle dialog events. The functions of this
+// structure will be called on the browser process UI thread.
+//
+#[repr(C)]
+pub struct _cef_dialog_handler_t {
+  //
+  // Base structure.
+  //
+  pub base: types::cef_base_t,
+
+  //
+  // Called to run a file chooser dialog. |mode| represents the type of dialog
+  // to display. |title| to the title to be used for the dialog and may be NULL
+  // to show the default title ("Open" or "Save" depending on the mode).
+  // |default_file_name| is the default file name to select in the dialog.
+  // |accept_types| is a list of valid lower-cased MIME types or file extensions
+  // specified in an input element and is used to restrict selectable files to
+  // such types. To display a custom dialog return true (1) and execute
+  // |callback| either inline or at a later time. To display the default dialog
+  // return false (0).
+  //
+  pub on_file_dialog: Option<extern "C" fn(this: *mut cef_dialog_handler_t,
+      browser: *mut interfaces::cef_browser_t,
+      mode: types::cef_file_dialog_mode_t, title: *const types::cef_string_t,
+      default_file_name: *const types::cef_string_t,
+      accept_types: types::cef_string_list_t,
+      callback: *mut interfaces::cef_file_dialog_callback_t) -> libc::c_int>,
+
+  //
+  // The reference count. This will only be present for Rust instances!
+  //
+  ref_count: uint,
+
+  //
+  // Extra data. This will only be present for Rust instances!
+  //
+  pub extra: u8,
+} 
+
+pub type cef_dialog_handler_t = _cef_dialog_handler_t;
+
+
+//
+// Implement this structure to handle dialog events. The functions of this
+// structure will be called on the browser process UI thread.
+//
+pub struct CefDialogHandler {
+  c_object: *mut cef_dialog_handler_t,
+}
+
+impl Clone for CefDialogHandler {
+  fn clone(&self) -> CefDialogHandler{
+    unsafe {
+      if !self.c_object.is_null() {
+        ((*self.c_object).base.add_ref.unwrap())(&mut (*self.c_object).base);
+      }
+      CefDialogHandler {
+        c_object: self.c_object,
+      }
+    }
+  }
+}
+
+impl Drop for CefDialogHandler {
+  fn drop(&mut self) {
+    unsafe {
+      if !self.c_object.is_null() {
+        ((*self.c_object).base.release.unwrap())(&mut (*self.c_object).base);
+      }
+    }
+  }
+}
+
+impl CefDialogHandler {
+  pub unsafe fn from_c_object(c_object: *mut cef_dialog_handler_t) -> CefDialogHandler {
+    CefDialogHandler {
+      c_object: c_object,
+    }
+  }
+
+  pub unsafe fn from_c_object_addref(c_object: *mut cef_dialog_handler_t) -> CefDialogHandler {
+    if !c_object.is_null() {
+      ((*c_object).base.add_ref.unwrap())(&mut (*c_object).base);
+    }
+    CefDialogHandler {
+      c_object: c_object,
+    }
+  }
+
+  pub fn c_object(&self) -> *mut cef_dialog_handler_t {
+    self.c_object
+  }
+
+  pub fn c_object_addrefed(&self) -> *mut cef_dialog_handler_t {
+    unsafe {
+      if !self.c_object.is_null() {
+        eutil::add_ref(self.c_object as *mut types::cef_base_t);
+      }
+      self.c_object
+    }
+  }
+
+  pub fn is_null_cef_object(&self) -> bool {
+    self.c_object.is_null()
+  }
+  pub fn is_not_null_cef_object(&self) -> bool {
+    !self.c_object.is_null()
+  }
+
+  //
+  // Called to run a file chooser dialog. |mode| represents the type of dialog
+  // to display. |title| to the title to be used for the dialog and may be NULL
+  // to show the default title ("Open" or "Save" depending on the mode).
+  // |default_file_name| is the default file name to select in the dialog.
+  // |accept_types| is a list of valid lower-cased MIME types or file extensions
+  // specified in an input element and is used to restrict selectable files to
+  // such types. To display a custom dialog return true (1) and execute
+  // |callback| either inline or at a later time. To display the default dialog
+  // return false (0).
+  //
+  pub fn on_file_dialog(&self, browser: interfaces::CefBrowser,
+      mode: types::cef_file_dialog_mode_t, title: &str,
+      default_file_name: &str, accept_types: Vec<String>,
+      callback: interfaces::CefFileDialogCallback) -> libc::c_int {
+    if self.c_object.is_null() {
+      panic!("called a CEF method on a null object")
+    }
+    unsafe {
+      CefWrap::to_rust(
+        ((*self.c_object).on_file_dialog.unwrap())(
+          self.c_object,
+          CefWrap::to_c(browser),
+          CefWrap::to_c(mode),
+          CefWrap::to_c(title),
+          CefWrap::to_c(default_file_name),
+          CefWrap::to_c(accept_types),
+          CefWrap::to_c(callback)))
+    }
+  }
+} 
+
+impl CefWrap<*mut cef_dialog_handler_t> for CefDialogHandler {
+  fn to_c(rust_object: CefDialogHandler) -> *mut cef_dialog_handler_t {
+    rust_object.c_object_addrefed()
+  }
+  unsafe fn to_rust(c_object: *mut cef_dialog_handler_t) -> CefDialogHandler {
+    CefDialogHandler::from_c_object_addref(c_object)
+  }
+}
+impl CefWrap<*mut cef_dialog_handler_t> for Option<CefDialogHandler> {
+  fn to_c(rust_object: Option<CefDialogHandler>) -> *mut cef_dialog_handler_t {
+    match rust_object {
+      None => ptr::null_mut(),
+      Some(rust_object) => rust_object.c_object_addrefed(),
+    }
+  }
+  unsafe fn to_rust(c_object: *mut cef_dialog_handler_t) -> Option<CefDialogHandler> {
+    if c_object.is_null() {
+      None
+    } else {
+      Some(CefDialogHandler::from_c_object_addref(c_object))
+    }
+  }
+}
+