From b484836dbc66424a6abda11693eb4e31929e0d40 Mon Sep 17 00:00:00 2001
From: Kunal Mohan <kunalmohan99@gmail.com>
Date: Sat, 27 Jun 2020 12:03:59 +0530
Subject: [PATCH] Ensure proper unmap of buffer

---
 components/script/dom/gpubuffer.rs | 22 +++++++++++-----------
 components/webgpu/lib.rs           | 29 +++++++++++++----------------
 2 files changed, 24 insertions(+), 27 deletions(-)

diff --git a/components/script/dom/gpubuffer.rs b/components/script/dom/gpubuffer.rs
index 8b1b80e6365..07c1c525359 100644
--- a/components/script/dom/gpubuffer.rs
+++ b/components/script/dom/gpubuffer.rs
@@ -146,17 +146,17 @@ impl GPUBufferMethods for GPUBuffer {
                 match ArrayBuffer::from(self.mapping.get()) {
                     Ok(array_buffer) => {
                         // Step 3.2
-                        if Some(GPUMapModeConstants::READ) != self.map_mode.get() {
-                            self.channel
-                                .0
-                                .send(WebGPURequest::UnmapBuffer {
-                                    device_id: self.device.0,
-                                    buffer_id: self.id().0,
-                                    array_buffer: array_buffer.to_vec(),
-                                    mapped_at_creation: self.map_mode.get() == None,
-                                })
-                                .unwrap();
-                        }
+                        self.channel
+                            .0
+                            .send(WebGPURequest::UnmapBuffer {
+                                buffer_id: self.id().0,
+                                array_buffer: array_buffer.to_vec(),
+                                is_map_read: self.map_mode.get() == Some(GPUMapModeConstants::READ),
+                                offset: self.mapping_range.borrow().start,
+                                size: self.mapping_range.borrow().end -
+                                    self.mapping_range.borrow().start,
+                            })
+                            .unwrap();
                         // Step 3.3
                         unsafe {
                             DetachArrayBuffer(*cx, self.mapping.handle());
diff --git a/components/webgpu/lib.rs b/components/webgpu/lib.rs
index 6eeb0824286..71f5e633e6b 100644
--- a/components/webgpu/lib.rs
+++ b/components/webgpu/lib.rs
@@ -198,10 +198,11 @@ pub enum WebGPURequest {
         image_key: webrender_api::ImageKey,
     },
     UnmapBuffer {
-        device_id: id::DeviceId,
         buffer_id: id::BufferId,
         array_buffer: Vec<u8>,
-        mapped_at_creation: bool,
+        is_map_read: bool,
+        offset: u64,
+        size: u64,
     },
 }
 
@@ -931,27 +932,23 @@ impl<'a> WGPU<'a> {
                         gfx_select!(buffer_id => global.buffer_unmap(buffer_id));
                     },
                     WebGPURequest::UnmapBuffer {
-                        device_id,
                         buffer_id,
                         array_buffer,
-                        mapped_at_creation,
+                        is_map_read,
+                        offset,
+                        size,
                     } => {
                         let global = &self.global;
-                        if mapped_at_creation {
-                            gfx_select!(device_id => global.queue_write_buffer(
-                                device_id,
+                        if !is_map_read {
+                            let map_ptr = gfx_select!(buffer_id => global.buffer_get_mapped_range(
                                 buffer_id,
-                                0,
-                                array_buffer.as_slice()
-                            ));
-                        } else {
-                            gfx_select!(buffer_id => global.device_set_buffer_sub_data(
-                                device_id,
-                                buffer_id,
-                                0,
-                                array_buffer.as_slice()
+                                offset,
+                                wgt::BufferSize::new(size)
                             ));
+                            unsafe { slice::from_raw_parts_mut(map_ptr, size as usize) }
+                                .copy_from_slice(&array_buffer);
                         }
+                        gfx_select!(buffer_id => global.buffer_unmap(buffer_id));
                     },
                 }
             }