webrender does not compile on Windows with feature=pathfinder

[fschutt]

After the latest pathfinder (currently pcwalton/pathfinder@235c51e) changes have been merged, webrender does not compile on Windows anymore:

   Compiling pathfinder_gfx_utils v0.1.0 (https://github.com/pcwalton/pathfinder#235c51e1)
   Compiling plane-split v0.8.0
   Compiling lyon_geom v0.10.0
   Compiling webrender_api v0.57.2 (https://github.com/servo/webrender?rev=1ff66239b728083a37c53c98d51e070d4aae8ca0#1ff66239)
   Compiling lyon_path v0.10.0
   Compiling pathfinder_font_renderer v0.3.0 (https://github.com/pcwalton/pathfinder#235c51e1)
   Compiling pathfinder_path_utils v0.1.0 (https://github.com/pcwalton/pathfinder#235c51e1)
   Compiling pathfinder_partitioner v0.1.0 (https://github.com/pcwalton/pathfinder#235c51e1)

error[E0061]: this function takes 2 parameters but 3 parameters were supplied
   --> C:\Users\Felix Schütt\.cargo\git\checkouts\webrender-c3596abe1cf4f320\1ff6623\webrender\src\glyph_rasterizer.rs:579:55
    |
579 |                         match pathfinder_font_context.glyph_dimensions(&pathfinder_font_instance,
    |                                                       ^^^^^^^^^^^^^^^^ expected 2 parameters

error[E0308]: mismatched types
   --> C:\Users\Felix Schütt\.cargo\git\checkouts\webrender-c3596abe1cf4f320\1ff6623\webrender\src\glyph_rasterizer.rs:582:29
    |
582 |                             Ok(glyph_dimensions) => glyph_dimensions,
    |                             ^^^^^^^^^^^^^^^^^^^^ expected enum `std::option::Option`, found enum `std::result::Result`
    |
    = note: expected type `std::option::Option<pathfinder_font_renderer::GlyphDimensions>`
               found type `std::result::Result<_, _>`

error[E0308]: mismatched types
   --> C:\Users\Felix Schütt\.cargo\git\checkouts\webrender-c3596abe1cf4f320\1ff6623\webrender\src\glyph_rasterizer.rs:583:29
    |
583 |                             Err(_) => continue,
    |                             ^^^^^^ expected enum `std::option::Option`, found enum `std::result::Result`
    |
    = note: expected type `std::option::Option<pathfinder_font_renderer::GlyphDimensions>`
               found type `std::result::Result<_, _>`

error[E0277]: the trait bound `*mut winapi::dwrite::IDWriteFactory: std::marker::Send` is not satisfied in `pathfinder_font_renderer::FontContext<webrender_api::FontKey>`
   --> C:\Users\Felix Schütt\.cargo\git\checkouts\webrender-c3596abe1cf4f320\1ff6623\webrender\src\glyph_rasterizer.rs:824:22
    |
824 |         self.workers.spawn(move || {
    |                      ^^^^^ `*mut winapi::dwrite::IDWriteFactory` cannot be sent between threads safely
    |
    = help: within `pathfinder_font_renderer::FontContext<webrender_api::FontKey>`, the trait `std::marker::Send` is not implemented for `*mut winapi::dwrite::IDWriteFactory`
    = note: required because it appears within the type `pathfinder_font_renderer::directwrite::com::PathfinderComPtr<winapi::dwrite::IDWriteFactory>`
    = note: required because it appears within the type `pathfinder_font_renderer::FontContext<webrender_api::FontKey>`
    = note: required because of the requirements on the impl of `std::marker::Send` for `std::sync::Mutex<pathfinder_font_renderer::FontContext<webrender_api::FontKey>>`
    = note: required because of the requirements on the impl of `std::marker::Send` for `std::ptr::Unique<std::sync::Mutex<pathfinder_font_renderer::FontContext<webrender_api::FontKey>>>`
    = note: required because it appears within the type `std::boxed::Box<std::sync::Mutex<pathfinder_font_renderer::FontContext<webrender_api::FontKey>>>`
    = note: required because it appears within the type `glyph_rasterizer::FontContexts`
    = note: required because of the requirements on the impl of `std::marker::Send` for `std::sync::Arc<glyph_rasterizer::FontContexts>`
    = note: required because it appears within the type `[closure@C:\Users\Felix Schütt\.cargo\git\checkouts\webrender-c3596abe1cf4f320\1ff6623\webrender\src\glyph_rasterizer.rs:824:28: 834:10 fonts_to_remove:std::vec::Vec<webrender_api::FontKey>, font_contexts:std::sync::Arc<glyph_rasterizer::FontContexts>]`

error[E0277]: the trait bound `*mut winapi::dwrite::IDWriteFontFace: std::marker::Send` is not satisfied in `pathfinder_font_renderer::directwrite::com::PathfinderComPtr<winapi::dwrite::IDWriteFontFace>`
   --> C:\Users\Felix Schütt\.cargo\git\checkouts\webrender-c3596abe1cf4f320\1ff6623\webrender\src\glyph_rasterizer.rs:824:22
    |
824 |         self.workers.spawn(move || {
    |                      ^^^^^ `*mut winapi::dwrite::IDWriteFontFace` cannot be sent between threads safely
    |
    = help: within `pathfinder_font_renderer::directwrite::com::PathfinderComPtr<winapi::dwrite::IDWriteFontFace>`, the trait `std::marker::Send` is not implemented for `*mut winapi::dwrite::IDWriteFontFace`
    = note: required because it appears within the type `pathfinder_font_renderer::directwrite::com::PathfinderComPtr<winapi::dwrite::IDWriteFontFace>`
    = note: required because of the requirements on the impl of `std::marker::Send` for `alloc::btree::node::Root<webrender_api::FontKey, pathfinder_font_renderer::directwrite::com::PathfinderComPtr<winapi::dwrite::IDWriteFontFace>>`
    = note: required because it appears within the type `std::collections::BTreeMap<webrender_api::FontKey, pathfinder_font_renderer::directwrite::com::PathfinderComPtr<winapi::dwrite::IDWriteFontFace>>`
    = note: required because it appears within the type `pathfinder_font_renderer::FontContext<webrender_api::FontKey>`
    = note: required because of the requirements on the impl of `std::marker::Send` for `std::sync::Mutex<pathfinder_font_renderer::FontContext<webrender_api::FontKey>>`
    = note: required because of the requirements on the impl of `std::marker::Send` for `std::ptr::Unique<std::sync::Mutex<pathfinder_font_renderer::FontContext<webrender_api::FontKey>>>`
    = note: required because it appears within the type `std::boxed::Box<std::sync::Mutex<pathfinder_font_renderer::FontContext<webrender_api::FontKey>>>`
    = note: required because it appears within the type `glyph_rasterizer::FontContexts`
    = note: required because of the requirements on the impl of `std::marker::Send` for `std::sync::Arc<glyph_rasterizer::FontContexts>`
    = note: required because it appears within the type `[closure@C:\Users\Felix Schütt\.cargo\git\checkouts\webrender-c3596abe1cf4f320\1ff6623\webrender\src\glyph_rasterizer.rs:824:28: 834:10 fonts_to_remove:std::vec::Vec<webrender_api::FontKey>, font_contexts:std::sync::Arc<glyph_rasterizer::FontContexts>]`

error[E0599]: no method named `add_native_font` found for type `&mut pathfinder_font_renderer::FontContext<webrender_api::FontKey>` in the current scope
   --> C:\Users\Felix Schütt\.cargo\git\checkouts\webrender-c3596abe1cf4f320\1ff6623\webrender\src\glyph_rasterizer.rs:870:27
    |
870 |                 drop(self.add_native_font(&font_key, NativeFontHandleWrapper(native_font_handle)))
    |                           ^^^^^^^^^^^^^^^

error[E0277]: the trait bound `*mut winapi::dwrite::IDWriteFactory: std::marker::Send` is not satisfied in `pathfinder_font_renderer::FontContext<webrender_api::FontKey>`
    --> C:\Users\Felix Schütt\.cargo\git\checkouts\webrender-c3596abe1cf4f320\1ff6623\webrender\src\renderer.rs:1633:61
     |
1633 |         thread::Builder::new().name(rb_thread_name.clone()).spawn(move || {
     |                                                             ^^^^^ `*mut winapi::dwrite::IDWriteFactory` cannot be sent between threads safely
     |
     = help: within `pathfinder_font_renderer::FontContext<webrender_api::FontKey>`, the trait `std::marker::Send` is not implemented for `*mut winapi::dwrite::IDWriteFactory`
     = note: required because it appears within the type `pathfinder_font_renderer::directwrite::com::PathfinderComPtr<winapi::dwrite::IDWriteFactory>`
     = note: required because it appears within the type `pathfinder_font_renderer::FontContext<webrender_api::FontKey>`
     = note: required because of the requirements on the impl of `std::marker::Send` for `std::sync::Mutex<pathfinder_font_renderer::FontContext<webrender_api::FontKey>>`
     = note: required because of the requirements on the impl of `std::marker::Send` for `std::ptr::Unique<std::sync::Mutex<pathfinder_font_renderer::FontContext<webrender_api::FontKey>>>`
     = note: required because it appears within the type `std::boxed::Box<std::sync::Mutex<pathfinder_font_renderer::FontContext<webrender_api::FontKey>>>`
     = note: required because it appears within the type `glyph_rasterizer::FontContexts`
     = note: required because of the requirements on the impl of `std::marker::Send` for `std::sync::Arc<glyph_rasterizer::FontContexts>`
     = note: required because it appears within the type `glyph_rasterizer::GlyphRasterizer`
     = note: required because it appears within the type `[closure@C:\Users\Felix Schütt\.cargo\git\checkouts\webrender-c3596abe1cf4f320\1ff6623\webrender\src\renderer.rs:1633:67: 1663:10 rb_thread_name:std::string::String, thread_listener_for_render_backend:std::sync::Arc<std::option::Option<std::boxed::Box<renderer::ThreadListener + std::marker::Send + std::marker::Sync>>>, max_device_size:u32, glyph_rasterizer:glyph_rasterizer::GlyphRasterizer, blob_image_renderer:std::option::Option<std::boxed::Box<webrender_api::BlobImageRenderer>>, api_rx:webrender_api::channel::MsgReceiver<webrender_api::ApiMsg>, payload_rx_for_backend:std::sync::mpsc::Receiver<webrender_api::channel::Payload>, result_tx:std::sync::mpsc::Sender<internal_types::ResultMsg>, scene_tx:std::sync::mpsc::Sender<scene_builder::SceneBuilderRequest>, scene_rx:std::sync::mpsc::Receiver<scene_builder::SceneBuilderResult>, device_pixel_ratio:f32, backend_notifier:std::boxed::Box<webrender_api::RenderNotifier>, config:frame_builder::FrameBuilderConfig, recorder:std::option::Option<std::boxed::Box<record::ApiRecordingReceiver>>, enable_render_on_scroll:bool, backend_profile_counters:profiler::BackendProfileCounters]`

error[E0277]: the trait bound `*mut winapi::dwrite::IDWriteFontFace: std::marker::Send` is not satisfied in `pathfinder_font_renderer::directwrite::com::PathfinderComPtr<winapi::dwrite::IDWriteFontFace>`
    --> C:\Users\Felix Schütt\.cargo\git\checkouts\webrender-c3596abe1cf4f320\1ff6623\webrender\src\renderer.rs:1633:61
     |
1633 |         thread::Builder::new().name(rb_thread_name.clone()).spawn(move || {
     |                                                             ^^^^^ `*mut winapi::dwrite::IDWriteFontFace` cannot be sent between threads safely
     |
     = help: within `pathfinder_font_renderer::directwrite::com::PathfinderComPtr<winapi::dwrite::IDWriteFontFace>`, the trait `std::marker::Send` is not implemented for `*mut winapi::dwrite::IDWriteFontFace`
     = note: required because it appears within the type `pathfinder_font_renderer::directwrite::com::PathfinderComPtr<winapi::dwrite::IDWriteFontFace>`
     = note: required because of the requirements on the impl of `std::marker::Send` for `alloc::btree::node::Root<webrender_api::FontKey, pathfinder_font_renderer::directwrite::com::PathfinderComPtr<winapi::dwrite::IDWriteFontFace>>`
     = note: required because it appears within the type `std::collections::BTreeMap<webrender_api::FontKey, pathfinder_font_renderer::directwrite::com::PathfinderComPtr<winapi::dwrite::IDWriteFontFace>>`
     = note: required because it appears within the type `pathfinder_font_renderer::FontContext<webrender_api::FontKey>`
     = note: required because of the requirements on the impl of `std::marker::Send` for `std::sync::Mutex<pathfinder_font_renderer::FontContext<webrender_api::FontKey>>`
     = note: required because of the requirements on the impl of `std::marker::Send` for `std::ptr::Unique<std::sync::Mutex<pathfinder_font_renderer::FontContext<webrender_api::FontKey>>>`
     = note: required because it appears within the type `std::boxed::Box<std::sync::Mutex<pathfinder_font_renderer::FontContext<webrender_api::FontKey>>>`
     = note: required because it appears within the type `glyph_rasterizer::FontContexts`
     = note: required because of the requirements on the impl of `std::marker::Send` for `std::sync::Arc<glyph_rasterizer::FontContexts>`
     = note: required because it appears within the type `glyph_rasterizer::GlyphRasterizer`
     = note: required because it appears within the type `[closure@C:\Users\Felix Schütt\.cargo\git\checkouts\webrender-c3596abe1cf4f320\1ff6623\webrender\src\renderer.rs:1633:67: 1663:10 rb_thread_name:std::string::String, thread_listener_for_render_backend:std::sync::Arc<std::option::Option<std::boxed::Box<renderer::ThreadListener + std::marker::Send + std::marker::Sync>>>, max_device_size:u32, glyph_rasterizer:glyph_rasterizer::GlyphRasterizer, blob_image_renderer:std::option::Option<std::boxed::Box<webrender_api::BlobImageRenderer>>, api_rx:webrender_api::channel::MsgReceiver<webrender_api::ApiMsg>, payload_rx_for_backend:std::sync::mpsc::Receiver<webrender_api::channel::Payload>, result_tx:std::sync::mpsc::Sender<internal_types::ResultMsg>, scene_tx:std::sync::mpsc::Sender<scene_builder::SceneBuilderRequest>, scene_rx:std::sync::mpsc::Receiver<scene_builder::SceneBuilderResult>, device_pixel_ratio:f32, backend_notifier:std::boxed::Box<webrender_api::RenderNotifier>, config:frame_builder::FrameBuilderConfig, recorder:std::option::Option<std::boxed::Box<record::ApiRecordingReceiver>>, enable_render_on_scroll:bool, backend_profile_counters:profiler::BackendProfileCounters]`

error: aborting due to 8 previous errors

error: Could not compile `webrender`.

To learn more, run the command again with --verbose.

Replicate with (on nightly-x86_64-pc-windows-msvc unchanged - rustc 1.27.0-nightly (0b72d48f8 2018-04-10)`:

cargo build --no-default-features --features="pathfinder"

Now, the problem of this is that, while pathfinder compiles fine, the corresponding webrender code didn't get adjusted to the new changes: For example, the glyph_dimensions function indeed takes 2 arguments now and returns an Option, but the corresponding webrender code for Windows uses 3 arguments and matches on a Result. I am not sure which version is the correct one (I think it's the one with the 2 arguments).

Please add pathfinder to Taskcluster, appveyor and Travis, so that this doesn't happen again.

[fschutt]

After #2705 is merged, there are still 4 build errors remaining because we can't share a raw pointer to IDWriteFactory and IDWriteFontFace across threads. But I think these errors have to be resolved in the pathfinder crate, not webrender.