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_resource_handler.rs

@@ -0,0 +1,340 @@
+// 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;
+
+//
+// Structure used to implement a custom request handler structure. The functions
+// of this structure will always be called on the IO thread.
+//
+#[repr(C)]
+pub struct _cef_resource_handler_t {
+  //
+  // Base structure.
+  //
+  pub base: types::cef_base_t,
+
+  //
+  // Begin processing the request. To handle the request return true (1) and
+  // call cef_callback_t::cont() once the response header information is
+  // available (cef_callback_t::cont() can also be called from inside this
+  // function if header information is available immediately). To cancel the
+  // request return false (0).
+  //
+  pub process_request: Option<extern "C" fn(this: *mut cef_resource_handler_t,
+      request: *mut interfaces::cef_request_t,
+      callback: *mut interfaces::cef_callback_t) -> libc::c_int>,
+
+  //
+  // Retrieve response header information. If the response length is not known
+  // set |response_length| to -1 and read_response() will be called until it
+  // returns false (0). If the response length is known set |response_length| to
+  // a positive value and read_response() will be called until it returns false
+  // (0) or the specified number of bytes have been read. Use the |response|
+  // object to set the mime type, http status code and other optional header
+  // values. To redirect the request to a new URL set |redirectUrl| to the new
+  // URL.
+  //
+  pub get_response_headers: Option<extern "C" fn(
+      this: *mut cef_resource_handler_t,
+      response: *mut interfaces::cef_response_t, response_length: *mut i64,
+      redirectUrl: *mut types::cef_string_t) -> ()>,
+
+  //
+  // Read response data. If data is available immediately copy up to
+  // |bytes_to_read| bytes into |data_out|, set |bytes_read| to the number of
+  // bytes copied, and return true (1). To read the data at a later time set
+  // |bytes_read| to 0, return true (1) and call cef_callback_t::cont() when the
+  // data is available. To indicate response completion return false (0).
+  //
+  pub read_response: Option<extern "C" fn(this: *mut cef_resource_handler_t,
+      data_out: *mut (), bytes_to_read: libc::c_int,
+      bytes_read: *mut libc::c_int,
+      callback: *mut interfaces::cef_callback_t) -> libc::c_int>,
+
+  //
+  // Return true (1) if the specified cookie can be sent with the request or
+  // false (0) otherwise. If false (0) is returned for any cookie then no
+  // cookies will be sent with the request.
+  //
+  pub can_get_cookie: Option<extern "C" fn(this: *mut cef_resource_handler_t,
+      cookie: *const interfaces::cef_cookie_t) -> libc::c_int>,
+
+  //
+  // Return true (1) if the specified cookie returned with the response can be
+  // set or false (0) otherwise.
+  //
+  pub can_set_cookie: Option<extern "C" fn(this: *mut cef_resource_handler_t,
+      cookie: *const interfaces::cef_cookie_t) -> libc::c_int>,
+
+  //
+  // Request processing has been canceled.
+  //
+  pub cancel: Option<extern "C" fn(this: *mut cef_resource_handler_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_resource_handler_t = _cef_resource_handler_t;
+
+
+//
+// Structure used to implement a custom request handler structure. The functions
+// of this structure will always be called on the IO thread.
+//
+pub struct CefResourceHandler {
+  c_object: *mut cef_resource_handler_t,
+}
+
+impl Clone for CefResourceHandler {
+  fn clone(&self) -> CefResourceHandler{
+    unsafe {
+      if !self.c_object.is_null() {
+        ((*self.c_object).base.add_ref.unwrap())(&mut (*self.c_object).base);
+      }
+      CefResourceHandler {
+        c_object: self.c_object,
+      }
+    }
+  }
+}
+
+impl Drop for CefResourceHandler {
+  fn drop(&mut self) {
+    unsafe {
+      if !self.c_object.is_null() {
+        ((*self.c_object).base.release.unwrap())(&mut (*self.c_object).base);
+      }
+    }
+  }
+}
+
+impl CefResourceHandler {
+  pub unsafe fn from_c_object(c_object: *mut cef_resource_handler_t) -> CefResourceHandler {
+    CefResourceHandler {
+      c_object: c_object,
+    }
+  }
+
+  pub unsafe fn from_c_object_addref(c_object: *mut cef_resource_handler_t) -> CefResourceHandler {
+    if !c_object.is_null() {
+      ((*c_object).base.add_ref.unwrap())(&mut (*c_object).base);
+    }
+    CefResourceHandler {
+      c_object: c_object,
+    }
+  }
+
+  pub fn c_object(&self) -> *mut cef_resource_handler_t {
+    self.c_object
+  }
+
+  pub fn c_object_addrefed(&self) -> *mut cef_resource_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()
+  }
+
+  //
+  // Begin processing the request. To handle the request return true (1) and
+  // call cef_callback_t::cont() once the response header information is
+  // available (cef_callback_t::cont() can also be called from inside this
+  // function if header information is available immediately). To cancel the
+  // request return false (0).
+  //
+  pub fn process_request(&self, request: interfaces::CefRequest,
+      callback: interfaces::CefCallback) -> 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).process_request.unwrap())(
+          self.c_object,
+          CefWrap::to_c(request),
+          CefWrap::to_c(callback)))
+    }
+  }
+
+  //
+  // Retrieve response header information. If the response length is not known
+  // set |response_length| to -1 and read_response() will be called until it
+  // returns false (0). If the response length is known set |response_length| to
+  // a positive value and read_response() will be called until it returns false
+  // (0) or the specified number of bytes have been read. Use the |response|
+  // object to set the mime type, http status code and other optional header
+  // values. To redirect the request to a new URL set |redirectUrl| to the new
+  // URL.
+  //
+  pub fn get_response_headers(&self, response: interfaces::CefResponse,
+      response_length: &mut i64, redirectUrl: *mut types::cef_string_t) -> (
+      ) {
+    if self.c_object.is_null() {
+      panic!("called a CEF method on a null object")
+    }
+    unsafe {
+      CefWrap::to_rust(
+        ((*self.c_object).get_response_headers.unwrap())(
+          self.c_object,
+          CefWrap::to_c(response),
+          CefWrap::to_c(response_length),
+          CefWrap::to_c(redirectUrl)))
+    }
+  }
+
+  //
+  // Read response data. If data is available immediately copy up to
+  // |bytes_to_read| bytes into |data_out|, set |bytes_read| to the number of
+  // bytes copied, and return true (1). To read the data at a later time set
+  // |bytes_read| to 0, return true (1) and call cef_callback_t::cont() when the
+  // data is available. To indicate response completion return false (0).
+  //
+  pub fn read_response(&self, data_out: &mut (), bytes_to_read: libc::c_int,
+      bytes_read: &mut libc::c_int,
+      callback: interfaces::CefCallback) -> 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).read_response.unwrap())(
+          self.c_object,
+          CefWrap::to_c(data_out),
+          CefWrap::to_c(bytes_to_read),
+          CefWrap::to_c(bytes_read),
+          CefWrap::to_c(callback)))
+    }
+  }
+
+  //
+  // Return true (1) if the specified cookie can be sent with the request or
+  // false (0) otherwise. If false (0) is returned for any cookie then no
+  // cookies will be sent with the request.
+  //
+  pub fn can_get_cookie(&self, cookie: &interfaces::CefCookie) -> 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).can_get_cookie.unwrap())(
+          self.c_object,
+          CefWrap::to_c(cookie)))
+    }
+  }
+
+  //
+  // Return true (1) if the specified cookie returned with the response can be
+  // set or false (0) otherwise.
+  //
+  pub fn can_set_cookie(&self, cookie: &interfaces::CefCookie) -> 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).can_set_cookie.unwrap())(
+          self.c_object,
+          CefWrap::to_c(cookie)))
+    }
+  }
+
+  //
+  // Request processing has been canceled.
+  //
+  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_resource_handler_t> for CefResourceHandler {
+  fn to_c(rust_object: CefResourceHandler) -> *mut cef_resource_handler_t {
+    rust_object.c_object_addrefed()
+  }
+  unsafe fn to_rust(c_object: *mut cef_resource_handler_t) -> CefResourceHandler {
+    CefResourceHandler::from_c_object_addref(c_object)
+  }
+}
+impl CefWrap<*mut cef_resource_handler_t> for Option<CefResourceHandler> {
+  fn to_c(rust_object: Option<CefResourceHandler>) -> *mut cef_resource_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_resource_handler_t) -> Option<CefResourceHandler> {
+    if c_object.is_null() {
+      None
+    } else {
+      Some(CefResourceHandler::from_c_object_addref(c_object))
+    }
+  }
+}
+