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Refactored Canvas to disallow null inline contexts. (#174530)

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One of the possible explanations for the crash in
https://github.com/flutter/flutter/issues/168210#issuecomment-3130088036
is a null inline pass context. This makes that statically impossible
(barring an allocation problem).

tests: exempt, just a refactor

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This commit is contained in:
gaaclarke 2025-08-27 22:04:17 -07:00 committed by GitHub
parent 066982b537
commit b897fb76a0
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GPG Key ID: B5690EEEBB952194
2 changed files with 68 additions and 53 deletions
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93
engine/src/flutter/impeller/display_list/canvas.cc
View File

@ -871,9 +871,10 @@ void Canvas::ClipGeometry(const Geometry& geometry,
if (clip_state_result.clip_did_change) {
// We only need to update the pass scissor if the clip state has changed.
SetClipScissor(clip_coverage_stack_.CurrentClipCoverage(),
*render_passes_.back().inline_pass_context->GetRenderPass(),
GetGlobalPassPosition());
SetClipScissor(
clip_coverage_stack_.CurrentClipCoverage(),
*render_passes_.back().GetInlinePassContext()->GetRenderPass(),
GetGlobalPassPosition());
}
++transform_stack_.back().clip_height;
@ -892,16 +893,16 @@ void Canvas::ClipGeometry(const Geometry& geometry,
entity.SetClipDepth(clip_depth);
GeometryResult geometry_result = geometry.GetPositionBuffer(
renderer_, //
entity, //
*render_passes_.back().inline_pass_context->GetRenderPass() //
renderer_, //
entity, //
*render_passes_.back().GetInlinePassContext()->GetRenderPass() //
);
clip_contents.SetGeometry(geometry_result);
clip_coverage_stack_.GetLastReplayResult().clip_contents.SetGeometry(
geometry_result);
clip_contents.Render(
renderer_, *render_passes_.back().inline_pass_context->GetRenderPass(),
renderer_, *render_passes_.back().GetInlinePassContext()->GetRenderPass(),
clip_depth);
}
@ -1217,9 +1218,9 @@ std::optional<Rect> Canvas::GetLocalCoverageLimit() const {
FML_CHECK(!render_passes_.empty());
const LazyRenderingConfig& back_render_pass = render_passes_.back();
std::shared_ptr<Texture> back_texture =
back_render_pass.inline_pass_context->GetTexture();
back_render_pass.GetInlinePassContext()->GetTexture();
FML_CHECK(back_texture) << "Context is valid:"
<< back_render_pass.inline_pass_context->IsValid();
<< back_render_pass.GetInlinePassContext()->IsValid();
// The maximum coverage of the subpass. Subpasses textures should never
// extend outside the parent pass texture or the current clip coverage.
@ -1509,7 +1510,7 @@ bool Canvas::Restore() {
auto lazy_render_pass = std::move(render_passes_.back());
render_passes_.pop_back();
// Force the render pass to be constructed if it never was.
lazy_render_pass.inline_pass_context->GetRenderPass();
lazy_render_pass.GetInlinePassContext()->GetRenderPass();
SaveLayerState save_layer_state = save_layer_state_.back();
save_layer_state_.pop_back();
@ -1517,12 +1518,12 @@ bool Canvas::Restore() {
std::shared_ptr<Contents> contents = CreateContentsForSubpassTarget(
save_layer_state.paint, //
lazy_render_pass.inline_pass_context->GetTexture(), //
lazy_render_pass.GetInlinePassContext()->GetTexture(), //
Matrix::MakeTranslation(Vector3{-global_pass_position}) * //
transform_stack_.back().transform //
);
lazy_render_pass.inline_pass_context->EndPass();
lazy_render_pass.GetInlinePassContext()->EndPass();
// Round the subpass texture position for pixel alignment with the parent
// pass render target. By default, we draw subpass textures with nearest
@ -1581,8 +1582,8 @@ bool Canvas::Restore() {
}
element_entity.Render(
renderer_, //
*render_passes_.back().inline_pass_context->GetRenderPass() //
renderer_, //
*render_passes_.back().GetInlinePassContext()->GetRenderPass() //
);
clip_coverage_stack_.PopSubpass();
transform_stack_.pop_back();
@ -1606,9 +1607,9 @@ bool Canvas::Restore() {
if (clip_state_result.clip_did_change) {
// We only need to update the pass scissor if the clip state has changed.
SetClipScissor(
clip_coverage_stack_.CurrentClipCoverage(), //
*render_passes_.back().inline_pass_context->GetRenderPass(), //
GetGlobalPassPosition() //
clip_coverage_stack_.CurrentClipCoverage(), //
*render_passes_.back().GetInlinePassContext()->GetRenderPass(), //
GetGlobalPassPosition() //
);
}
}
@ -1805,11 +1806,12 @@ void Canvas::AddRenderEntityToCurrentPass(Entity& entity, bool reuse_depth) {
// with the current backdrop.
if (render_passes_.back().IsApplyingClearColor()) {
std::optional<Color> maybe_color = entity.AsBackgroundColor(
render_passes_.back().inline_pass_context->GetTexture()->GetSize());
render_passes_.back().GetInlinePassContext()->GetTexture()->GetSize());
if (maybe_color.has_value()) {
Color color = maybe_color.value();
RenderTarget& render_target = render_passes_.back()
.inline_pass_context->GetPassTarget()
.GetInlinePassContext()
->GetPassTarget()
.GetRenderTarget();
ColorAttachment attachment = render_target.GetColorAttachment(0);
// Attachment.clear color needs to be premultiplied at all times, but the
@ -1872,7 +1874,7 @@ void Canvas::AddRenderEntityToCurrentPass(Entity& entity, bool reuse_depth) {
}
const std::shared_ptr<RenderPass>& result =
render_passes_.back().inline_pass_context->GetRenderPass();
render_passes_.back().GetInlinePassContext()->GetRenderPass();
if (!result) {
// Failure to produce a render pass should be explained by specific errors
// in `InlinePassContext::GetRenderPass()`, so avoid log spam and don't
@ -1884,7 +1886,7 @@ void Canvas::AddRenderEntityToCurrentPass(Entity& entity, bool reuse_depth) {
}
RenderPass& Canvas::GetCurrentRenderPass() const {
return *render_passes_.back().inline_pass_context->GetRenderPass();
return *render_passes_.back().GetInlinePassContext()->GetRenderPass();
}
void Canvas::SetBackdropData(
@ -1912,8 +1914,8 @@ std::shared_ptr<Texture> Canvas::FlipBackdrop(Point global_pass_position,
// In cases where there are no contents, we
// could instead check the clear color and initialize a 1x2 CPU texture
// instead of ending the pass.
rendering_config.inline_pass_context->GetRenderPass();
if (!rendering_config.inline_pass_context->EndPass()) {
rendering_config.GetInlinePassContext()->GetRenderPass();
if (!rendering_config.GetInlinePassContext()->EndPass()) {
VALIDATION_LOG
<< "Failed to end the current render pass in order to read from "
"the backdrop texture and apply an advanced blend or backdrop "
@ -1921,23 +1923,19 @@ std::shared_ptr<Texture> Canvas::FlipBackdrop(Point global_pass_position,
// Note: adding this render pass ensures there are no later crashes from
// unbalanced save layers. Ideally, this method would return false and the
// renderer could handle that by terminating dispatch.
render_passes_.push_back(LazyRenderingConfig(
renderer_, std::move(rendering_config.entity_pass_target),
std::move(rendering_config.inline_pass_context)));
render_passes_.emplace_back(std::move(rendering_config));
return nullptr;
}
const std::shared_ptr<Texture>& input_texture =
rendering_config.inline_pass_context->GetTexture();
rendering_config.GetInlinePassContext()->GetTexture();
if (!input_texture) {
VALIDATION_LOG << "Failed to fetch the color texture in order to "
"apply an advanced blend or backdrop filter.";
// Note: see above.
render_passes_.push_back(LazyRenderingConfig(
renderer_, std::move(rendering_config.entity_pass_target),
std::move(rendering_config.inline_pass_context)));
render_passes_.emplace_back(std::move(rendering_config));
return nullptr;
}
@ -1960,17 +1958,15 @@ std::shared_ptr<Texture> Canvas::FlipBackdrop(Point global_pass_position,
LazyRenderingConfig(renderer_, std::move(entity_pass_target)));
requires_readback_ = false;
} else {
render_passes_.push_back(LazyRenderingConfig(
renderer_, std::move(rendering_config.entity_pass_target),
std::move(rendering_config.inline_pass_context)));
render_passes_.emplace_back(std::move(rendering_config));
// If the current texture is being cached for a BDF we need to ensure we
// don't recycle it during recording; remove it from the entity pass target.
if (should_remove_texture) {
render_passes_.back().entity_pass_target->RemoveSecondary();
render_passes_.back().GetEntityPassTarget()->RemoveSecondary();
}
}
RenderPass& current_render_pass =
*render_passes_.back().inline_pass_context->GetRenderPass();
*render_passes_.back().GetInlinePassContext()->GetRenderPass();
// Eagerly restore the BDF contents.
@ -2028,7 +2024,8 @@ bool Canvas::BlitToOnscreen(bool is_onscreen) {
auto command_buffer = renderer_.GetContext()->CreateCommandBuffer();
command_buffer->SetLabel("EntityPass Root Command Buffer");
auto offscreen_target = render_passes_.back()
.inline_pass_context->GetPassTarget()
.GetInlinePassContext()
->GetPassTarget()
.GetRenderTarget();
if (SupportsBlitToOnscreen()) {
auto blit_pass = command_buffer->CreateBlitPass();
@ -2093,8 +2090,8 @@ bool Canvas::EnsureFinalMipmapGeneration() const {
void Canvas::EndReplay() {
FML_DCHECK(render_passes_.size() == 1u);
render_passes_.back().inline_pass_context->GetRenderPass();
render_passes_.back().inline_pass_context->EndPass(
render_passes_.back().GetInlinePassContext()->GetRenderPass();
render_passes_.back().GetInlinePassContext()->EndPass(
/*is_onscreen=*/!requires_readback_ && is_onscreen_);
backdrop_data_.clear();
@ -2119,4 +2116,24 @@ void Canvas::EndReplay() {
Initialize(initial_cull_rect_);
}
LazyRenderingConfig::LazyRenderingConfig(
ContentContext& renderer,
std::unique_ptr<EntityPassTarget> p_entity_pass_target)
: entity_pass_target_(std::move(p_entity_pass_target)) {
inline_pass_context_ =
std::make_unique<InlinePassContext>(renderer, *entity_pass_target_);
}
bool LazyRenderingConfig::IsApplyingClearColor() const {
return !inline_pass_context_->IsActive();
}
EntityPassTarget* LazyRenderingConfig::GetEntityPassTarget() const {
return entity_pass_target_.get();
}
InlinePassContext* LazyRenderingConfig::GetInlinePassContext() const {
return inline_pass_context_.get();
}
} // namespace impeller

28
engine/src/flutter/impeller/display_list/canvas.h
View File

@ -96,25 +96,23 @@ enum class ContentBoundsPromise {
kMayClipContents,
};
struct LazyRenderingConfig {
std::unique_ptr<EntityPassTarget> entity_pass_target;
std::unique_ptr<InlinePassContext> inline_pass_context;
class LazyRenderingConfig {
public:
LazyRenderingConfig(ContentContext& renderer,
std::unique_ptr<EntityPassTarget> p_entity_pass_target);
LazyRenderingConfig(LazyRenderingConfig&&) = default;
/// Whether or not the clear color texture can still be updated.
bool IsApplyingClearColor() const { return !inline_pass_context->IsActive(); }
bool IsApplyingClearColor() const;
LazyRenderingConfig(ContentContext& renderer,
std::unique_ptr<EntityPassTarget> p_entity_pass_target)
: entity_pass_target(std::move(p_entity_pass_target)) {
inline_pass_context =
std::make_unique<InlinePassContext>(renderer, *entity_pass_target);
}
EntityPassTarget* GetEntityPassTarget() const;
LazyRenderingConfig(ContentContext& renderer,
std::unique_ptr<EntityPassTarget> entity_pass_target,
std::unique_ptr<InlinePassContext> inline_pass_context)
: entity_pass_target(std::move(entity_pass_target)),
inline_pass_context(std::move(inline_pass_context)) {}
InlinePassContext* GetInlinePassContext() const;
private:
std::unique_ptr<EntityPassTarget> entity_pass_target_;
std::unique_ptr<InlinePassContext> inline_pass_context_;
};
class Canvas {