Florin Malita

This commit implements a **robustness improvement** within the **text rendering subsystem**, specifically addressing potential vulnerabilities in **GPU glyph caching**. It modifies the `readStrikeData` function in `src/text/gpu/SkChromeRemoteGlyphCache.cpp` to create a local copy of volatile strike data. This **defensive copying** prevents time-of-check to time-of-use (TOCTOU) issues during deserialization, as the input data originates from untrusted and shared memory. By ensuring internal APIs operate on a stable data snapshot, this change enhances the **security and stability** of glyph deserialization.

This commit **updates the `libpng` dependency** to version **1.6.56**, ensuring the project utilizes the latest stable release of the PNG image library. It modifies the project's **dependency management configuration** by updating the commit hashes in `DEPS` and `bazel/deps.json`, and the version in `infra/bots/deps/deps_gen.go`. This **maintenance chore** provides consumers of `libpng` within the project with the latest bug fixes, security patches, and performance improvements.

This commit implements a **test infrastructure improvement** by modifying the **Skia continuous integration (CI) system**. It introduces a condition in `infra/bots/gen_tasks_logic/dm_flags.go` to **skip the `Skottie_Shaper_CTStrict` test** when `NativeFonts` are not enabled. This **maintenance** change addresses **test unreliability** observed in environments lacking native font support, preventing spurious failures. By conditionally disabling this specific test, the commit enhances the stability and reliability of the **Skottie rendering engine's shaping tests** within the automated build process.

This commit delivers a critical **performance fix** for the **SkPathBuilder** by optimizing its internal memory reservation strategy. It addresses a pathological performance issue where appending simple shapes caused frequent reallocations due to `incReserve` always reserving exact storage; now, `incReserve` defaults to allowing storage growth, preventing this overhead. The change introduces a new `Reserve` option to `SkPathBuilder::addRaw` for explicit control over exact allocations when final counts are known, and refactors several internal call sites in `src/core/SkPathBuilder.cpp`, `src/core/SkPathData.cpp`, and `src/pathops/SkPathWriter.cpp` to leverage this. This significantly **improves performance** for operations involving repeated appends of simple shapes, as demonstrated by benchmarks showing orders of magnitude speedup.

This commit **fixes a bug** in the **`SkDescriptor`** module by enforcing a critical **4-byte alignment** requirement for all length values. Previously, the deserialization path did not validate this, potentially leading to issues with malformed data. The `isValid()` method in `src/core/SkDescriptor.cpp` is updated to reject descriptors with unaligned lengths, improving the **robustness** of `SkDescriptor` handling. This change prevents potential data corruption or undefined behavior when processing `SkDescriptor` objects, and a new test case in `tests/DescriptorTest.cpp` confirms that `SkDescriptor::MakeFromBuffer` now correctly rejects such invalid descriptors.

This commit introduces a **new line breaking mode** for the **CoreText-backed SkShaper** (`SkShaper_CoreText`) to resolve issues with **Skottie's text auto-sizing**. Previously, `CoreText` would break words mid-line, preventing the horizontal overflow signal needed for Skottie's auto-sizing algorithm. This **new capability** adds a `LineBreakMode` enum and implements logic within `SkShaper_CoreText` to detect and merge mid-word breaks, forcing proper horizontal overflow. This ensures **Skottie's text auto-sizing functions correctly** when using `CoreText`, with the `SkottieSlide` viewer updated to utilize this strict mode.

This commit performs **code cleanup** by **removing the `sk_float_rsqrt_portable` function** from Skia's **floating point utilities** defined in `include/private/base/SkFloatingPoint.h`. The function was identified as both unused and redundant, sharing an identical implementation with the standard `sk_float_rsqrt`. This **refactoring** effort **streamlines the codebase** by eliminating dead code, improving maintainability without any functional impact on the project.

This commit **refactors** the **base math utilities** within `src/base/SkMathPriv.h` by **removing the custom `SkPopCount_portable` implementation**. The `SkPopCount` function now directly utilizes the **standard library's `std::popcount`**, which is a portable and often optimized solution for counting set bits. Concurrently, several other `constexpr` math helper functions, such as `SkCLZ`, `SkCTZ`, `SkNextLog2`, and `SkNextPow2`, have been updated to be `static`. This **maintenance** effort streamlines the codebase by adopting standard library features and improving the encapsulation of these core utility functions.

This commit performs a significant **refactoring** of the **core math utilities** by **removing obsolete portable versions** of functions like `SkCLZ_portable`, `SkNextLog2_portable`, and `SkNextPow2_portable`. It **modernizes** the standard `SkCLZ`, `SkCTZ`, and related helpers by making them `constexpr`, enabling compile-time evaluation. This change impacts various **GPU modules** including Ganesh and Graphite, where usages of the portable functions are updated to their standard `constexpr` counterparts, and addresses a specific clang-cl quirk with warning suppression. The overall effect is a **cleaner and more efficient codebase** due to the elimination of redundant code and improved compile-time performance for these fundamental operations.

This commit introduces a **new capability** to the **Skottie viewer**, enabling users to dynamically toggle **CoreText-based text shaping**. A new keybind 'C' is added to `tools/viewer/SkottieSlide.cpp` to control this preference, which is stored in the `fPreferCoretext` member variable within the `SkottieSlide` class. This enhancement allows developers to easily test and compare text rendering behavior using CoreText, impacting how text-heavy animations are displayed and debugged within the viewer.

This commit performs a **code cleanup** by **removing** the `SkNthSet` class from the Skia codebase. This data structure was identified as **unused** and no longer referenced by any active components, making it **dead code**. The change is a **maintenance** effort to improve code hygiene and reduce the overall codebase footprint. There is no functional impact on any features or modules, as the removed component was not being utilized.

This commit **enhances the robustness** of the **SkPath module** by integrating new assertions into the `SkPath::Iter` class. Specifically, these assertions validate the consistency of internal verb pointers within the `setPath` and `next` methods, particularly when handling **empty paths**. This **maintenance** and **quality assurance** effort prevents potential future bugs and ensures the correct behavior of path iteration. A new `path_empty_iter` test case was also added to explicitly verify this critical edge case, improving the overall **reliability and correctness** of path processing.

This commit **enhances** the **Bazel macOS toolchain** by adding `_LocationEssentials.framework` and `AVRouting.Framework` to the `FRAMEWORK_GLOB` list within `toolchain/download_mac_toolchain.bzl`. This **expands the set of indirect frameworks** that are automatically downloaded and made available to macOS builds. The change ensures that projects relying on these specific system frameworks can build correctly without manual intervention. This **maintenance** update improves the robustness and completeness of the macOS build environment for Bazel-based projects.

This commit introduces **variable font loading capabilities** to **Skottie**, enabling more dynamic and expressive typography within animations. It adds a **new capability** by introducing an optional `fVariation` property to font definitions, allowing users to specify variation parameters like weight (`wght`) or slant (`slnt`) as a dictionary of axis tags and values. The **Skottie text rendering subsystem** now parses these variation parameters from JSON and applies them when resolving native typefaces, significantly enhancing control over font appearance.

This commit introduces a **new font management strategy** for **Skottie WASM**, replacing the reliance on the `ResourceProvider::loadTypeface` callback with a dedicated, data-driven font manager. This **architectural change**, primarily affecting the `modules/canvaskit/skottie_bindings.cpp` module, is a **new feature** that significantly **improves font resolution capabilities**. It enables proper **font fallback** when multiple fonts are used and, more importantly, adds support for **variable font style resolution**, a critical feature previously unavailable. This enhancement ensures more accurate and robust rendering of complex typography within Skottie animations in a WASM environment.

This commit **fixes a bug** in the **embedded font manager** (`SkFontMgr_custom_embedded.cpp`) where the `load_font_from_data` function was not correctly observing the `instanceIndex`. Previously, this oversight caused all related typefaces to appear identical, despite being intended to have different styles. The change modifies `load_font_from_data` to properly incorporate the `instanceIndex` into the `faceIndex` parameter when creating `SkFontData`. This **bug fix** ensures **correct font style differentiation** for embedded fonts, preventing incorrect rendering and style application.

This commit **refactors** the test data by relocating the `invalid_jpeg.jpg` file from the general `images/` directory to a more appropriate `invalid_images/` subdirectory. This **maintenance** change ensures that test resources containing invalid data are properly categorized and separated from valid image assets, improving the organization of the test suite. The `jpeg_invalid_stream_state` test within `tests/CodecTest.cpp` is updated to correctly reference the new path for this invalid JPEG, maintaining the integrity of the **codec testing framework**.

This commit **fixes a critical bug** in the **Skia codec subsystem** that could leave `SkJpegCodec` and other image codecs in an invalid stream state after failed incremental decode attempts. Previously, flawed stream rewind logic could corrupt the stream, leading to issues like incorrect buffer sizing for subsequent decodes. The **fix** introduces a new virtual function, `onSupportsIncrementalDecode`, allowing codecs to declare incremental support without consuming stream data, thereby preventing stream corruption. This **refactoring** removes the problematic rewind hacks from `SkCodec::startIncrementalDecode` and `SkCodec::startScanlineDecode`, improving the robustness of **image decoding** across various formats like JPEG, ICO, PNG, and Wuffs. A new test `jpeg_invalid_stream_state` was added to verify the correct stream state handling.

This commit **fixes a regression** in **Skia's path handling** where methods operating on paths were inadvertently discarding existing content in the destination path. Specifically, functions such as `filterPath` in `SkPathEffect.cpp`, `getSegment` in `SkPathMeasure.cpp`, and `FillPathWithPaint` in `SkPathUtils.cpp` are updated to initialize their `SkPathBuilder` with the destination path's current content. This **bug fix** ensures that operations involving **mutable path effects** correctly append or modify paths as intended, preventing data loss and restoring the expected behavior.

This commit **re-lands** the **initial implementation** of a **Rust FFI layer** for **ICC profile parsing**, leveraging the `moxcms` crate. It introduces a **new capability** within the **Skia codec module** to parse ICC profiles using Rust, providing an alternative to the existing SkCMS implementation. The change integrates this Rust functionality via C++ FFI, updating **GN** and **Bazel** build configurations to include the new `rust/icc` components and the `moxcms` dependency. This lays the groundwork for future use by other rustified codecs supporting ICC, controlled by the `skia_use_rust_icc` flag, and includes comprehensive unit tests.