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sourcekit-lsp/Sources/SemanticIndex/CheckedIndex.swift
2024-05-17 13:27:51 -07:00

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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
import Foundation
@preconcurrency import IndexStoreDB
import LSPLogging
import LanguageServerProtocol
/// Essentially a `DocumentManager` from the `SourceKitLSP` module.
///
/// Protocol is needed because the `SemanticIndex` module is lower-level than the `SourceKitLSP` module.
public protocol InMemoryDocumentManager {
/// Returns true if the file at the given URL has a different content in the document manager than on-disk. This is
/// the case if the user made edits to the file but didn't save them yet.
func fileHasInMemoryModifications(_ url: URL) -> Bool
}
public enum IndexCheckLevel {
/// Consider the index out-of-date only if the source file has been deleted on disk.
///
/// This is usually a good default because: When a file gets modified, it's likely that some of the line:column
/// locations in it are still correct eg. if only one line is modified and if lines are inserted/deleted all
/// locations above are still correct.
/// For locations that are out of date, showing stale results is one of the best ways of communicating to the user
/// that the index is out-of-date and that they need to rebuild. We might want to reconsider this default when we have
/// background indexing.
case deletedFiles
/// Consider the index out-of-date if the source file has been deleted or modified on disk.
case modifiedFiles
/// Consider the index out-of-date if the source file has been deleted or modified on disk or if there are
/// in-memory modifications in the given `DocumentManager`.
case inMemoryModifiedFiles(InMemoryDocumentManager)
}
/// A wrapper around `IndexStoreDB` that checks if returned symbol occurrences are up-to-date with regard to a
/// `IndexCheckLevel`.
///
/// - SeeAlso: Comment on `IndexOutOfDateChecker`
public final class CheckedIndex {
private var checker: IndexOutOfDateChecker
private let index: IndexStoreDB
fileprivate init(index: IndexStoreDB, checkLevel: IndexCheckLevel) {
self.index = index
self.checker = IndexOutOfDateChecker(checkLevel: checkLevel)
}
public var unchecked: UncheckedIndex {
return UncheckedIndex(index)
}
@discardableResult
public func forEachSymbolOccurrence(
byUSR usr: String,
roles: SymbolRole,
_ body: @escaping (SymbolOccurrence) -> Bool
) -> Bool {
index.forEachSymbolOccurrence(byUSR: usr, roles: roles) { occurrence in
guard self.checker.isUpToDate(occurrence.location) else {
return true // continue
}
return body(occurrence)
}
}
public func occurrences(ofUSR usr: String, roles: SymbolRole) -> [SymbolOccurrence] {
return index.occurrences(ofUSR: usr, roles: roles).filter { checker.isUpToDate($0.location) }
}
public func occurrences(relatedToUSR usr: String, roles: SymbolRole) -> [SymbolOccurrence] {
return index.occurrences(relatedToUSR: usr, roles: roles).filter { checker.isUpToDate($0.location) }
}
@discardableResult public func forEachCanonicalSymbolOccurrence(
containing pattern: String,
anchorStart: Bool,
anchorEnd: Bool,
subsequence: Bool,
ignoreCase: Bool,
body: @escaping (SymbolOccurrence) -> Bool
) -> Bool {
index.forEachCanonicalSymbolOccurrence(
containing: pattern,
anchorStart: anchorStart,
anchorEnd: anchorEnd,
subsequence: subsequence,
ignoreCase: ignoreCase
) { occurrence in
guard self.checker.isUpToDate(occurrence.location) else {
return true // continue
}
return body(occurrence)
}
}
public func symbols(inFilePath path: String) -> [Symbol] {
guard self.hasUpToDateUnit(for: URL(fileURLWithPath: path, isDirectory: false)) else {
return []
}
return index.symbols(inFilePath: path)
}
/// Returns all unit test symbol in unit files that reference one of the main files in `mainFilePaths`.
public func unitTests(referencedByMainFiles mainFilePaths: [String]) -> [SymbolOccurrence] {
return index.unitTests(referencedByMainFiles: mainFilePaths).filter { checker.isUpToDate($0.location) }
}
/// Returns all the files that (transitively) include the header file at the given path.
///
/// If `crossLanguage` is set to `true`, Swift files that import a header through a module will also be reported.
public func mainFilesContainingFile(uri: DocumentURI, crossLanguage: Bool = false) -> [DocumentURI] {
return index.mainFilesContainingFile(path: uri.pseudoPath, crossLanguage: crossLanguage).compactMap {
let url = URL(fileURLWithPath: $0)
guard checker.indexHasUpToDateUnit(for: url, mainFile: nil, index: self.index) else {
return nil
}
return DocumentURI(url)
}
}
/// Returns all unit test symbols in the index.
public func unitTests() -> [SymbolOccurrence] {
return index.unitTests().filter { checker.isUpToDate($0.location) }
}
/// Return `true` if a unit file has been indexed for the given file path after its last modification date.
///
/// This means that at least a single build configuration of this file has been indexed since its last modification.
///
/// If `mainFile` is passed, then `url` is a header file that won't have a unit associated with it. `mainFile` is
/// assumed to be a file that imports `url`. To check that `url` has an up-to-date unit, check that the latest unit
/// for `mainFile` is newer than the mtime of the header file at `url`.
public func hasUpToDateUnit(for url: URL, mainFile: URL? = nil) -> Bool {
return checker.indexHasUpToDateUnit(for: url, mainFile: mainFile, index: index)
}
/// Returns true if the file at the given URL has a different content in the document manager than on-disk. This is
/// the case if the user made edits to the file but didn't save them yet.
///
/// - Important: This must only be called on a `CheckedIndex` with a `checkLevel` of `inMemoryModifiedFiles`
public func fileHasInMemoryModifications(_ url: URL) -> Bool {
return checker.fileHasInMemoryModifications(url)
}
}
/// A wrapper around `IndexStoreDB` that allows the retrieval of a `CheckedIndex` with a specified check level or the
/// access of the underlying `IndexStoreDB`. This makes sure that accesses to the raw `IndexStoreDB` are explicit (by
/// calling `underlyingIndexStoreDB`) and we don't accidentally call into the `IndexStoreDB` when we wanted a
/// `CheckedIndex`.
public struct UncheckedIndex: Sendable {
public let underlyingIndexStoreDB: IndexStoreDB
public init?(_ index: IndexStoreDB?) {
guard let index else {
return nil
}
self.underlyingIndexStoreDB = index
}
public init(_ index: IndexStoreDB) {
self.underlyingIndexStoreDB = index
}
public func checked(for checkLevel: IndexCheckLevel) -> CheckedIndex {
return CheckedIndex(index: underlyingIndexStoreDB, checkLevel: checkLevel)
}
public func symbolProvider(for sourceFilePath: String) -> SymbolProviderKind? {
return underlyingIndexStoreDB.symbolProvider(for: sourceFilePath)
}
/// Wait for IndexStoreDB to be updated based on new unit files written to disk.
public func pollForUnitChangesAndWait() {
self.underlyingIndexStoreDB.pollForUnitChangesAndWait()
}
}
/// Helper class to check if symbols from the index are up-to-date or if the source file has been modified after it was
/// indexed. Modifications include both changes to the file on disk as well as modifications to the file that have not
/// been saved to disk (ie. changes that only live in `DocumentManager`).
///
/// The checker caches mod dates of source files. It should thus not be long lived. Its intended lifespan is the
/// evaluation of a single request.
private struct IndexOutOfDateChecker {
private let checkLevel: IndexCheckLevel
/// The last modification time of a file. Can also represent the fact that the file does not exist.
private enum ModificationTime {
case fileDoesNotExist
case date(Date)
}
private enum Error: Swift.Error, CustomStringConvertible {
case fileAttributesDontHaveModificationDate
var description: String {
switch self {
case .fileAttributesDontHaveModificationDate:
return "File attributes don't contain a modification date"
}
}
}
/// Caches whether a file URL has modifications in `documentManager` that haven't been saved to disk yet.
private var fileHasInMemoryModificationsCache: [URL: Bool] = [:]
/// File URLs to modification times that have already been computed.
private var modTimeCache: [URL: ModificationTime] = [:]
/// File URLs to whether they exist on the file system
private var fileExistsCache: [URL: Bool] = [:]
init(checkLevel: IndexCheckLevel) {
self.checkLevel = checkLevel
}
// MARK: - Public interface
/// Returns `true` if the source file for the given symbol location exists and has not been modified after it has been
/// indexed.
mutating func isUpToDate(_ symbolLocation: SymbolLocation) -> Bool {
let url = URL(fileURLWithPath: symbolLocation.path, isDirectory: false)
switch checkLevel {
case .inMemoryModifiedFiles(let documentManager):
if fileHasInMemoryModifications(url, documentManager: documentManager) {
return false
}
fallthrough
case .modifiedFiles:
do {
let sourceFileModificationDate = try modificationDate(of: url)
switch sourceFileModificationDate {
case .fileDoesNotExist:
return false
case .date(let sourceFileModificationDate):
return sourceFileModificationDate <= symbolLocation.timestamp
}
} catch {
logger.fault("Unable to determine if SymbolLocation is up-to-date: \(error.forLogging)")
return true
}
case .deletedFiles:
return fileExists(at: url)
}
}
/// Return `true` if a unit file has been indexed for the given file path after its last modification date.
///
/// This means that at least a single build configuration of this file has been indexed since its last modification.
///
/// If `mainFile` is passed, then `filePath` is a header file that won't have a unit associated with it. `mainFile` is
/// assumed to be a file that imports `url`. To check that `url` has an up-to-date unit, check that the latest unit
/// for `mainFile` is newer than the mtime of the header file at `url`.
mutating func indexHasUpToDateUnit(for filePath: URL, mainFile: URL?, index: IndexStoreDB) -> Bool {
switch checkLevel {
case .inMemoryModifiedFiles(let documentManager):
if fileHasInMemoryModifications(filePath, documentManager: documentManager) {
// If there are in-memory modifications to the file, we can't have an up-to-date unit since we only index files
// on disk.
return false
}
// If there are no in-memory modifications check if there are on-disk modifications.
fallthrough
case .modifiedFiles:
guard let lastUnitDate = index.dateOfLatestUnitFor(filePath: (mainFile ?? filePath).path) else {
return false
}
do {
let sourceModificationDate = try modificationDate(of: filePath)
switch sourceModificationDate {
case .fileDoesNotExist:
return false
case .date(let sourceModificationDate):
return sourceModificationDate <= lastUnitDate
}
} catch {
logger.fault("Unable to determine if source file has up-to-date unit: \(error.forLogging)")
return true
}
case .deletedFiles:
// If we are asked if the index has an up-to-date unit for a source file, we can reasonably assume that this
// source file exists (otherwise, why are we doing the query at all). Thus, there's nothing to check here.
return true
}
}
// MARK: - Cached check primitives
/// `documentManager` must always be the same between calls to `hasFileInMemoryModifications` since it is not part of
/// the cache key. This is fine because we always assume the `documentManager` to come from the associated value of
/// `CheckLevel.imMemoryModifiedFiles`, which is constant.
private mutating func fileHasInMemoryModifications(_ url: URL, documentManager: InMemoryDocumentManager) -> Bool {
if let cached = fileHasInMemoryModificationsCache[url] {
return cached
}
let hasInMemoryModifications = documentManager.fileHasInMemoryModifications(url)
fileHasInMemoryModificationsCache[url] = hasInMemoryModifications
return hasInMemoryModifications
}
/// Returns true if the file at the given URL has a different content in the document manager than on-disk. This is
/// the case if the user made edits to the file but didn't save them yet.
///
/// - Important: This must only be called on an `IndexOutOfDateChecker` with a `checkLevel` of `inMemoryModifiedFiles`
mutating func fileHasInMemoryModifications(_ url: URL) -> Bool {
switch checkLevel {
case .inMemoryModifiedFiles(let documentManager):
return fileHasInMemoryModifications(url, documentManager: documentManager)
case .modifiedFiles, .deletedFiles:
logger.fault(
"fileHasInMemoryModifications(at:) must only be called on an `IndexOutOfDateChecker` with check level .inMemoryModifiedFiles"
)
return false
}
}
private func modificationDateUncached(of url: URL) throws -> ModificationTime {
do {
let attributes = try FileManager.default.attributesOfItem(atPath: url.resolvingSymlinksInPath().path)
guard let modificationDate = attributes[FileAttributeKey.modificationDate] as? Date else {
throw Error.fileAttributesDontHaveModificationDate
}
return .date(modificationDate)
} catch let error as NSError where error.domain == NSCocoaErrorDomain && error.code == NSFileReadNoSuchFileError {
return .fileDoesNotExist
}
}
private mutating func modificationDate(of url: URL) throws -> ModificationTime {
if let cached = modTimeCache[url] {
return cached
}
let modTime = try modificationDateUncached(of: url)
modTimeCache[url] = modTime
return modTime
}
private mutating func fileExists(at url: URL) -> Bool {
if let cached = fileExistsCache[url] {
return cached
}
let fileExists = FileManager.default.fileExists(atPath: url.path)
fileExistsCache[url] = fileExists
return fileExists
}
}