src/tint/lang/wgsl/ls/file.h

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#ifndef SRC_TINT_LANG_WGSL_LS_FILE_H_
#define SRC_TINT_LANG_WGSL_LS_FILE_H_

#include <limits>
#include <memory>
#include <string>
#include <vector>

#include "src/tint/lang/wgsl/ast/node.h"
#include "src/tint/lang/wgsl/program/program.h"
#include "src/tint/utils/diagnostic/source.h"

namespace tint::wgsl::ls {

/// File represents an open language-server WGSL file ("document").
class File {
  public:
    /// The source file
    std::unique_ptr<Source::File> source;
    /// The current version of the file. Incremented with each change.
    int64_t version = 0;
    /// The parsed and resolved Program
    Program program;
    /// A source-ordered list of AST nodes.
    std::vector<const ast::Node*> nodes;

    /// Constructor
    File(std::unique_ptr<Source::File>&& source_, int64_t version_, Program program_);

    /// A structure holding source text and it's range in the file.
    struct TextAndRange {
        std::string text;
        Source::Range range;
    };

    /// @returns all the references to the symbol at the location @p l in the file.
    /// @param l the source location to lookup the symbol.
    /// @param include_declaration if true, the declaration of @p l will be included in the returned
    /// list.
    std::vector<Source::Range> References(Source::Location l, bool include_declaration);

    /// @returns the definition of the symbol at the location @p l in the file.
    std::optional<TextAndRange> Definition(Source::Location l);

    /// @returns the inner-most semantic node at the location @p l in the file.
    /// @tparam T the type or subtype of the node to scan for.
    template <typename T = sem::Node>
    const T* NodeAt(Source::Location l) const {
        // TODO(bclayton): This is a brute-force search. Optimize.
        size_t best_len = std::numeric_limits<uint32_t>::max();
        const T* best_node = nullptr;
        for (auto* node : nodes) {
            if (node->source.range.begin.line == node->source.range.end.line &&
                node->source.range.begin <= l && node->source.range.end >= l) {
                if (auto* sem =
                        As<T, CastFlags::kDontErrorOnImpossibleCast>(program.Sem().Get(node))) {
                    size_t len = node->source.range.end.column - node->source.range.begin.column;
                    if (len < best_len) {
                        best_len = len;
                        best_node = sem;
                    }
                }
            }
        }
        return best_node;
    }
};

}  // namespace tint::wgsl::ls

#endif  // SRC_TINT_LANG_WGSL_LS_FILE_H_