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_urlrequest.rs

@@ -0,0 +1,599 @@
+// 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 make a URL request. URL requests are not associated with a
+// browser instance so no cef_client_t callbacks will be executed. URL requests
+// can be created on any valid CEF thread in either the browser or render
+// process. Once created the functions of the URL request object must be
+// accessed on the same thread that created it.
+//
+#[repr(C)]
+pub struct _cef_urlrequest_t {
+  //
+  // Base structure.
+  //
+  pub base: types::cef_base_t,
+
+  //
+  // Returns the request object used to create this URL request. The returned
+  // object is read-only and should not be modified.
+  //
+  pub get_request: Option<extern "C" fn(
+      this: *mut cef_urlrequest_t) -> *mut interfaces::cef_request_t>,
+
+  //
+  // Returns the client.
+  //
+  pub get_client: Option<extern "C" fn(
+      this: *mut cef_urlrequest_t) -> *mut interfaces::cef_urlrequest_client_t>,
+
+  //
+  // Returns the request status.
+  //
+  pub get_request_status: Option<extern "C" fn(
+      this: *mut cef_urlrequest_t) -> types::cef_urlrequest_status_t>,
+
+  //
+  // Returns the request error if status is UR_CANCELED or UR_FAILED, or 0
+  // otherwise.
+  //
+  pub get_request_error: Option<extern "C" fn(
+      this: *mut cef_urlrequest_t) -> types::cef_errorcode_t>,
+
+  //
+  // Returns the response, or NULL if no response information is available.
+  // Response information will only be available after the upload has completed.
+  // The returned object is read-only and should not be modified.
+  //
+  pub get_response: Option<extern "C" fn(
+      this: *mut cef_urlrequest_t) -> *mut interfaces::cef_response_t>,
+
+  //
+  // Cancel the request.
+  //
+  pub cancel: Option<extern "C" fn(this: *mut cef_urlrequest_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_urlrequest_t = _cef_urlrequest_t;
+
+
+//
+// Structure used to make a URL request. URL requests are not associated with a
+// browser instance so no cef_client_t callbacks will be executed. URL requests
+// can be created on any valid CEF thread in either the browser or render
+// process. Once created the functions of the URL request object must be
+// accessed on the same thread that created it.
+//
+pub struct CefURLRequest {
+  c_object: *mut cef_urlrequest_t,
+}
+
+impl Clone for CefURLRequest {
+  fn clone(&self) -> CefURLRequest{
+    unsafe {
+      if !self.c_object.is_null() {
+        ((*self.c_object).base.add_ref.unwrap())(&mut (*self.c_object).base);
+      }
+      CefURLRequest {
+        c_object: self.c_object,
+      }
+    }
+  }
+}
+
+impl Drop for CefURLRequest {
+  fn drop(&mut self) {
+    unsafe {
+      if !self.c_object.is_null() {
+        ((*self.c_object).base.release.unwrap())(&mut (*self.c_object).base);
+      }
+    }
+  }
+}
+
+impl CefURLRequest {
+  pub unsafe fn from_c_object(c_object: *mut cef_urlrequest_t) -> CefURLRequest {
+    CefURLRequest {
+      c_object: c_object,
+    }
+  }
+
+  pub unsafe fn from_c_object_addref(c_object: *mut cef_urlrequest_t) -> CefURLRequest {
+    if !c_object.is_null() {
+      ((*c_object).base.add_ref.unwrap())(&mut (*c_object).base);
+    }
+    CefURLRequest {
+      c_object: c_object,
+    }
+  }
+
+  pub fn c_object(&self) -> *mut cef_urlrequest_t {
+    self.c_object
+  }
+
+  pub fn c_object_addrefed(&self) -> *mut cef_urlrequest_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()
+  }
+
+  //
+  // Returns the request object used to create this URL request. The returned
+  // object is read-only and should not be modified.
+  //
+  pub fn get_request(&self) -> interfaces::CefRequest {
+    if self.c_object.is_null() {
+      panic!("called a CEF method on a null object")
+    }
+    unsafe {
+      CefWrap::to_rust(
+        ((*self.c_object).get_request.unwrap())(
+          self.c_object))
+    }
+  }
+
+  //
+  // Returns the client.
+  //
+  pub fn get_client(&self) -> interfaces::CefURLRequestClient {
+    if self.c_object.is_null() {
+      panic!("called a CEF method on a null object")
+    }
+    unsafe {
+      CefWrap::to_rust(
+        ((*self.c_object).get_client.unwrap())(
+          self.c_object))
+    }
+  }
+
+  //
+  // Returns the request status.
+  //
+  pub fn get_request_status(&self) -> types::cef_urlrequest_status_t {
+    if self.c_object.is_null() {
+      panic!("called a CEF method on a null object")
+    }
+    unsafe {
+      CefWrap::to_rust(
+        ((*self.c_object).get_request_status.unwrap())(
+          self.c_object))
+    }
+  }
+
+  //
+  // Returns the request error if status is UR_CANCELED or UR_FAILED, or 0
+  // otherwise.
+  //
+  pub fn get_request_error(&self) -> types::cef_errorcode_t {
+    if self.c_object.is_null() {
+      panic!("called a CEF method on a null object")
+    }
+    unsafe {
+      CefWrap::to_rust(
+        ((*self.c_object).get_request_error.unwrap())(
+          self.c_object))
+    }
+  }
+
+  //
+  // Returns the response, or NULL if no response information is available.
+  // Response information will only be available after the upload has completed.
+  // The returned object is read-only and should not be modified.
+  //
+  pub fn get_response(&self) -> interfaces::CefResponse {
+    if self.c_object.is_null() {
+      panic!("called a CEF method on a null object")
+    }
+    unsafe {
+      CefWrap::to_rust(
+        ((*self.c_object).get_response.unwrap())(
+          self.c_object))
+    }
+  }
+
+  //
+  // Cancel the request.
+  //
+  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))
+    }
+  }
+
+  //
+  // Create a new URL request. Only GET, POST, HEAD, DELETE and PUT request
+  // functions are supported. Multiple post data elements are not supported and
+  // elements of type PDE_TYPE_FILE are only supported for requests originating
+  // from the browser process. Requests originating from the render process will
+  // receive the same handling as requests originating from Web content -- if
+  // the response contains Content-Disposition or Mime-Type header values that
+  // would not normally be rendered then the response may receive special
+  // handling inside the browser (for example, via the file download code path
+  // instead of the URL request code path). The |request| object will be marked
+  // as read-only after calling this function.
+  //
+  pub fn create(request: interfaces::CefRequest,
+      client: interfaces::CefURLRequestClient) -> interfaces::CefURLRequest {
+    unsafe {
+      CefWrap::to_rust(
+        ::urlrequest::cef_urlrequest_create(
+          CefWrap::to_c(request),
+          CefWrap::to_c(client)))
+    }
+  }
+} 
+
+impl CefWrap<*mut cef_urlrequest_t> for CefURLRequest {
+  fn to_c(rust_object: CefURLRequest) -> *mut cef_urlrequest_t {
+    rust_object.c_object_addrefed()
+  }
+  unsafe fn to_rust(c_object: *mut cef_urlrequest_t) -> CefURLRequest {
+    CefURLRequest::from_c_object_addref(c_object)
+  }
+}
+impl CefWrap<*mut cef_urlrequest_t> for Option<CefURLRequest> {
+  fn to_c(rust_object: Option<CefURLRequest>) -> *mut cef_urlrequest_t {
+    match rust_object {
+      None => ptr::null_mut(),
+      Some(rust_object) => rust_object.c_object_addrefed(),
+    }
+  }
+  unsafe fn to_rust(c_object: *mut cef_urlrequest_t) -> Option<CefURLRequest> {
+    if c_object.is_null() {
+      None
+    } else {
+      Some(CefURLRequest::from_c_object_addref(c_object))
+    }
+  }
+}
+
+
+//
+// Structure that should be implemented by the cef_urlrequest_t client. The
+// functions of this structure will be called on the same thread that created
+// the request unless otherwise documented.
+//
+#[repr(C)]
+pub struct _cef_urlrequest_client_t {
+  //
+  // Base structure.
+  //
+  pub base: types::cef_base_t,
+
+  //
+  // Notifies the client that the request has completed. Use the
+  // cef_urlrequest_t::GetRequestStatus function to determine if the request was
+  // successful or not.
+  //
+  pub on_request_complete: Option<extern "C" fn(
+      this: *mut cef_urlrequest_client_t,
+      request: *mut interfaces::cef_urlrequest_t) -> ()>,
+
+  //
+  // Notifies the client of upload progress. |current| denotes the number of
+  // bytes sent so far and |total| is the total size of uploading data (or -1 if
+  // chunked upload is enabled). This function will only be called if the
+  // UR_FLAG_REPORT_UPLOAD_PROGRESS flag is set on the request.
+  //
+  pub on_upload_progress: Option<extern "C" fn(
+      this: *mut cef_urlrequest_client_t,
+      request: *mut interfaces::cef_urlrequest_t, current: u64,
+      total: u64) -> ()>,
+
+  //
+  // Notifies the client of download progress. |current| denotes the number of
+  // bytes received up to the call and |total| is the expected total size of the
+  // response (or -1 if not determined).
+  //
+  pub on_download_progress: Option<extern "C" fn(
+      this: *mut cef_urlrequest_client_t,
+      request: *mut interfaces::cef_urlrequest_t, current: u64,
+      total: u64) -> ()>,
+
+  //
+  // Called when some part of the response is read. |data| contains the current
+  // bytes received since the last call. This function will not be called if the
+  // UR_FLAG_NO_DOWNLOAD_DATA flag is set on the request.
+  //
+  pub on_download_data: Option<extern "C" fn(this: *mut cef_urlrequest_client_t,
+      request: *mut interfaces::cef_urlrequest_t, data: *const (),
+      data_length: libc::size_t) -> ()>,
+
+  //
+  // Called on the IO thread when the browser needs credentials from the user.
+  // |isProxy| indicates whether the host is a proxy server. |host| contains the
+  // hostname and |port| contains the port number. Return true (1) to continue
+  // the request and call cef_auth_callback_t::cont() when the authentication
+  // information is available. Return false (0) to cancel the request. This
+  // function will only be called for requests initiated from the browser
+  // process.
+  //
+  pub get_auth_credentials: Option<extern "C" fn(
+      this: *mut cef_urlrequest_client_t, isProxy: libc::c_int,
+      host: *const types::cef_string_t, port: libc::c_int,
+      realm: *const types::cef_string_t, scheme: *const types::cef_string_t,
+      callback: *mut interfaces::cef_auth_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_urlrequest_client_t = _cef_urlrequest_client_t;
+
+
+//
+// Structure that should be implemented by the cef_urlrequest_t client. The
+// functions of this structure will be called on the same thread that created
+// the request unless otherwise documented.
+//
+pub struct CefURLRequestClient {
+  c_object: *mut cef_urlrequest_client_t,
+}
+
+impl Clone for CefURLRequestClient {
+  fn clone(&self) -> CefURLRequestClient{
+    unsafe {
+      if !self.c_object.is_null() {
+        ((*self.c_object).base.add_ref.unwrap())(&mut (*self.c_object).base);
+      }
+      CefURLRequestClient {
+        c_object: self.c_object,
+      }
+    }
+  }
+}
+
+impl Drop for CefURLRequestClient {
+  fn drop(&mut self) {
+    unsafe {
+      if !self.c_object.is_null() {
+        ((*self.c_object).base.release.unwrap())(&mut (*self.c_object).base);
+      }
+    }
+  }
+}
+
+impl CefURLRequestClient {
+  pub unsafe fn from_c_object(c_object: *mut cef_urlrequest_client_t) -> CefURLRequestClient {
+    CefURLRequestClient {
+      c_object: c_object,
+    }
+  }
+
+  pub unsafe fn from_c_object_addref(c_object: *mut cef_urlrequest_client_t) -> CefURLRequestClient {
+    if !c_object.is_null() {
+      ((*c_object).base.add_ref.unwrap())(&mut (*c_object).base);
+    }
+    CefURLRequestClient {
+      c_object: c_object,
+    }
+  }
+
+  pub fn c_object(&self) -> *mut cef_urlrequest_client_t {
+    self.c_object
+  }
+
+  pub fn c_object_addrefed(&self) -> *mut cef_urlrequest_client_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()
+  }
+
+  //
+  // Notifies the client that the request has completed. Use the
+  // cef_urlrequest_t::GetRequestStatus function to determine if the request was
+  // successful or not.
+  //
+  pub fn on_request_complete(&self, request: interfaces::CefURLRequest) -> () {
+    if self.c_object.is_null() {
+      panic!("called a CEF method on a null object")
+    }
+    unsafe {
+      CefWrap::to_rust(
+        ((*self.c_object).on_request_complete.unwrap())(
+          self.c_object,
+          CefWrap::to_c(request)))
+    }
+  }
+
+  //
+  // Notifies the client of upload progress. |current| denotes the number of
+  // bytes sent so far and |total| is the total size of uploading data (or -1 if
+  // chunked upload is enabled). This function will only be called if the
+  // UR_FLAG_REPORT_UPLOAD_PROGRESS flag is set on the request.
+  //
+  pub fn on_upload_progress(&self, request: interfaces::CefURLRequest,
+      current: u64, total: u64) -> () {
+    if self.c_object.is_null() {
+      panic!("called a CEF method on a null object")
+    }
+    unsafe {
+      CefWrap::to_rust(
+        ((*self.c_object).on_upload_progress.unwrap())(
+          self.c_object,
+          CefWrap::to_c(request),
+          CefWrap::to_c(current),
+          CefWrap::to_c(total)))
+    }
+  }
+
+  //
+  // Notifies the client of download progress. |current| denotes the number of
+  // bytes received up to the call and |total| is the expected total size of the
+  // response (or -1 if not determined).
+  //
+  pub fn on_download_progress(&self, request: interfaces::CefURLRequest,
+      current: u64, total: u64) -> () {
+    if self.c_object.is_null() {
+      panic!("called a CEF method on a null object")
+    }
+    unsafe {
+      CefWrap::to_rust(
+        ((*self.c_object).on_download_progress.unwrap())(
+          self.c_object,
+          CefWrap::to_c(request),
+          CefWrap::to_c(current),
+          CefWrap::to_c(total)))
+    }
+  }
+
+  //
+  // Called when some part of the response is read. |data| contains the current
+  // bytes received since the last call. This function will not be called if the
+  // UR_FLAG_NO_DOWNLOAD_DATA flag is set on the request.
+  //
+  pub fn on_download_data(&self, request: interfaces::CefURLRequest, data: &(),
+      data_length: libc::size_t) -> () {
+    if self.c_object.is_null() {
+      panic!("called a CEF method on a null object")
+    }
+    unsafe {
+      CefWrap::to_rust(
+        ((*self.c_object).on_download_data.unwrap())(
+          self.c_object,
+          CefWrap::to_c(request),
+          CefWrap::to_c(data),
+          CefWrap::to_c(data_length)))
+    }
+  }
+
+  //
+  // Called on the IO thread when the browser needs credentials from the user.
+  // |isProxy| indicates whether the host is a proxy server. |host| contains the
+  // hostname and |port| contains the port number. Return true (1) to continue
+  // the request and call cef_auth_callback_t::cont() when the authentication
+  // information is available. Return false (0) to cancel the request. This
+  // function will only be called for requests initiated from the browser
+  // process.
+  //
+  pub fn get_auth_credentials(&self, isProxy: libc::c_int, host: &str,
+      port: libc::c_int, realm: &str, scheme: &str,
+      callback: interfaces::CefAuthCallback) -> 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).get_auth_credentials.unwrap())(
+          self.c_object,
+          CefWrap::to_c(isProxy),
+          CefWrap::to_c(host),
+          CefWrap::to_c(port),
+          CefWrap::to_c(realm),
+          CefWrap::to_c(scheme),
+          CefWrap::to_c(callback)))
+    }
+  }
+} 
+
+impl CefWrap<*mut cef_urlrequest_client_t> for CefURLRequestClient {
+  fn to_c(rust_object: CefURLRequestClient) -> *mut cef_urlrequest_client_t {
+    rust_object.c_object_addrefed()
+  }
+  unsafe fn to_rust(c_object: *mut cef_urlrequest_client_t) -> CefURLRequestClient {
+    CefURLRequestClient::from_c_object_addref(c_object)
+  }
+}
+impl CefWrap<*mut cef_urlrequest_client_t> for Option<CefURLRequestClient> {
+  fn to_c(rust_object: Option<CefURLRequestClient>) -> *mut cef_urlrequest_client_t {
+    match rust_object {
+      None => ptr::null_mut(),
+      Some(rust_object) => rust_object.c_object_addrefed(),
+    }
+  }
+  unsafe fn to_rust(c_object: *mut cef_urlrequest_client_t) -> Option<CefURLRequestClient> {
+    if c_object.is_null() {
+      None
+    } else {
+      Some(CefURLRequestClient::from_c_object_addref(c_object))
+    }
+  }
+}
+