From eb8a8943f61d334cc523750ee66886a2b249744b Mon Sep 17 00:00:00 2001 From: Jonathan Tatum Date: Mon, 29 Jun 2026 12:25:41 -0700 Subject: [PATCH] Add support for creating a subspan view of a cel::Source. PiperOrigin-RevId: 939969141 --- common/source.cc | 45 +++++++++++++++++++++++++++++++++++++++++++ common/source.h | 32 ++++++++++++++++++++++++++++++ common/source_test.cc | 39 +++++++++++++++++++++++++++++++++++++ 3 files changed, 116 insertions(+) diff --git a/common/source.cc b/common/source.cc index 5fa4cca0e..f268bc833 100644 --- a/common/source.cc +++ b/common/source.cc @@ -585,6 +585,51 @@ absl::optional> Source::FindLine( return std::make_pair(line, line_offsets[static_cast(line) - 2]); } +SourceSubrange::SourceSubrange(const Source& source, SourceRange range) + : source_(source), range_(range) { + SourcePosition size = source_.content().size(); + ABSL_DCHECK(range_.begin >= 0); + ABSL_DCHECK(range_.begin <= size); + ABSL_DCHECK(range_.end >= range_.begin); + ABSL_DCHECK(range_.end <= size); + if (range_.begin < 0) { + range_.begin = 0; + } + if (range_.begin > size) { + range_.begin = size; + } + if (range_.end < range_.begin) { + range_.end = range_.begin; + } + if (range_.end > size) { + range_.end = size; + } + for (const auto& line_offset : source_.line_offsets()) { + if (line_offset > range_.begin && line_offset <= range_.end) { + line_offsets_.push_back(line_offset - range_.begin); + } + } + line_offsets_.push_back(range_.end - range_.begin + 1); +} + +SourceContentView SourceSubrange::content() const { + auto parent_content = source_.content(); + if (parent_content.empty() || range_.begin >= range_.end) { + return EmptyContentView(); + } + return absl::visit( + [this](auto view) { + return SourceContentView( + view.subspan(static_cast(range_.begin), + static_cast(range_.end - range_.begin))); + }, + parent_content.view_); +} + +absl::Span SourceSubrange::line_offsets() const { + return absl::MakeConstSpan(line_offsets_); +} + absl::StatusOr NewSource(absl::string_view content, std::string description) { return common_internal::NewSourceImpl(std::move(description), content, diff --git a/common/source.h b/common/source.h index 6453363a8..b3968453f 100644 --- a/common/source.h +++ b/common/source.h @@ -22,6 +22,7 @@ #include "absl/base/attributes.h" #include "absl/base/nullability.h" +#include "absl/container/inlined_vector.h" #include "absl/status/statusor.h" #include "absl/strings/cord.h" #include "absl/strings/string_view.h" @@ -36,6 +37,7 @@ class SourceImpl; } // namespace common_internal class Source; +class SourceSubrange; // SourcePosition represents an offset in source text. using SourcePosition = int32_t; @@ -94,6 +96,7 @@ class SourceContentView final { private: friend class Source; + friend class SourceSubrange; constexpr SourceContentView() = default; @@ -178,6 +181,7 @@ class Source { private: friend class common_internal::SourceImpl; + friend class SourceSubrange; Source() = default; @@ -187,6 +191,34 @@ class Source { SourcePosition position) const; }; +// `SourceSubrange` is a view of a subrange fo an underlying `Source` object. +// Intended to be used when the CEL expression is embedded in a larger text +// representation (such as a.celpolicy). +// +// The parent `Source` must outlive this object. +class SourceSubrange final : public Source { + public: + SourceSubrange(const Source& source ABSL_ATTRIBUTE_LIFETIME_BOUND, + SourceRange range); + + absl::string_view description() const ABSL_ATTRIBUTE_LIFETIME_BOUND override { + return source_.description(); + } + + // Returns a view of the underlying expression text. + ContentView content() const ABSL_ATTRIBUTE_LIFETIME_BOUND override; + + // Returns a `absl::Span` of `SourcePosition` which represent the positions + // where new lines occur. + absl::Span line_offsets() const + ABSL_ATTRIBUTE_LIFETIME_BOUND override; + + private: + const Source& source_; + SourceRange range_; + absl::InlinedVector line_offsets_; +}; + using SourcePtr = std::unique_ptr; absl::StatusOr NewSource( diff --git a/common/source_test.cc b/common/source_test.cc index 30a2ce9b0..e620d3dd8 100644 --- a/common/source_test.cc +++ b/common/source_test.cc @@ -223,5 +223,44 @@ TEST(Source, DisplayErrorLocationFullWidth) { "\n | .．＾"); } +TEST(SourceSubrange, Description) { + ASSERT_OK_AND_ASSIGN(auto source, NewSource("hello world", "subrange-test")); + SourceSubrange subrange(*source, SourceRange{0, 5}); + EXPECT_THAT(subrange.description(), Eq("subrange-test")); +} + +TEST(SourceSubrange, Content) { + ASSERT_OK_AND_ASSIGN(auto source, NewSource("hello world", "subrange-test")); + SourceSubrange subrange(*source, SourceRange{6, 11}); + EXPECT_THAT(subrange.content().ToString(), Eq("world")); +} + +TEST(SourceSubrange, ContentEmpty) { + ASSERT_OK_AND_ASSIGN(auto source, NewSource("hello world", "subrange-test")); + SourceSubrange subrange(*source, SourceRange{5, 5}); + EXPECT_THAT(subrange.content().ToString(), Eq("")); +} + +TEST(SourceSubrange, LineOffsetsNoNewlines) { + ASSERT_OK_AND_ASSIGN(auto source, + NewSource("hello\nworld\n", "subrange-test")); + SourceSubrange subrange(*source, SourceRange{0, 5}); + EXPECT_THAT(subrange.line_offsets(), ElementsAre(6)); +} + +TEST(SourceSubrange, LineOffsetsWithNewlines) { + ASSERT_OK_AND_ASSIGN(auto source, + NewSource("hello\nworld\ncel", "subrange-test")); + SourceSubrange subrange(*source, SourceRange{0, 11}); + EXPECT_THAT(subrange.line_offsets(), ElementsAre(6, 12)); +} + +TEST(SourceSubrange, LineOffsetsMiddleSubrange) { + ASSERT_OK_AND_ASSIGN(auto source, + NewSource("hello\nworld\ncel\ncpp", "subrange-test")); + SourceSubrange subrange(*source, SourceRange{6, 15}); + EXPECT_THAT(subrange.line_offsets(), ElementsAre(6, 10)); +} + } // namespace } // namespace cel