//===--- ModuleDependencies.h - Module Dependencies -------------*- C++ -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 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
//
//===----------------------------------------------------------------------===//
//
// This file implements data structures for capturing module dependencies.
//
//===----------------------------------------------------------------------===//
#include "swift/AST/ModuleDependencies.h"
#include "swift/AST/Decl.h"
#include "swift/AST/SourceFile.h"
#include "swift/Frontend/Frontend.h"
using namespace swift;

ModuleDependenciesStorageBase::~ModuleDependenciesStorageBase() {}

bool ModuleDependencies::isSwiftModule() const {
  return isSwiftInterfaceModule() || isSwiftSourceModule() ||
         isSwiftBinaryModule() || isSwiftPlaceholderModule();
}

ModuleDependenciesKind &operator++(ModuleDependenciesKind &e) {
  if (e == ModuleDependenciesKind::LastKind) {
    llvm_unreachable(
        "Attempting to increment last enum value on ModuleDependenciesKind");
  }
  e = ModuleDependenciesKind(
      static_cast<std::underlying_type<ModuleDependenciesKind>::type>(e) + 1);
  return e;
}

bool ModuleDependencies::isSwiftInterfaceModule() const {
  return isa<SwiftInterfaceModuleDependenciesStorage>(storage.get());
}

bool ModuleDependencies::isSwiftSourceModule() const {
  return isa<SwiftSourceModuleDependenciesStorage>(storage.get());
}

bool ModuleDependencies::isSwiftBinaryModule() const {
  return isa<SwiftBinaryModuleDependencyStorage>(storage.get());
}

bool ModuleDependencies::isSwiftPlaceholderModule() const {
  return isa<SwiftPlaceholderModuleDependencyStorage>(storage.get());
}

bool ModuleDependencies::isClangModule() const {
  return isa<ClangModuleDependenciesStorage>(storage.get());
}

/// Retrieve the dependencies for a Swift textual interface module.
const SwiftInterfaceModuleDependenciesStorage *
ModuleDependencies::getAsSwiftInterfaceModule() const {
  return dyn_cast<SwiftInterfaceModuleDependenciesStorage>(storage.get());
}

const SwiftSourceModuleDependenciesStorage *
ModuleDependencies::getAsSwiftSourceModule() const {
  return dyn_cast<SwiftSourceModuleDependenciesStorage>(storage.get());
}

/// Retrieve the dependencies for a binary Swift dependency module.
const SwiftBinaryModuleDependencyStorage *
ModuleDependencies::getAsSwiftBinaryModule() const {
  return dyn_cast<SwiftBinaryModuleDependencyStorage>(storage.get());
}

/// Retrieve the dependencies for a Clang module.
const ClangModuleDependenciesStorage *
ModuleDependencies::getAsClangModule() const {
  return dyn_cast<ClangModuleDependenciesStorage>(storage.get());
}

/// Retrieve the dependencies for a placeholder dependency module stub.
const SwiftPlaceholderModuleDependencyStorage *
ModuleDependencies::getAsPlaceholderDependencyModule() const {
  return dyn_cast<SwiftPlaceholderModuleDependencyStorage>(storage.get());
}

void ModuleDependencies::addModuleDependency(
    StringRef module, llvm::StringSet<> *alreadyAddedModules) {
  if (!alreadyAddedModules || alreadyAddedModules->insert(module).second)
    storage->moduleDependencies.push_back(module.str());
}

void ModuleDependencies::addModuleDependencies(
    const SourceFile &sf, llvm::StringSet<> &alreadyAddedModules) {
  // Add all of the module dependencies.
  SmallVector<Decl *, 32> decls;
  sf.getTopLevelDecls(decls);
  for (auto decl : decls) {
    auto importDecl = dyn_cast<ImportDecl>(decl);
    if (!importDecl)
      continue;

    ImportPath::Builder scratch;
    auto realPath = importDecl->getRealModulePath(scratch);
    addModuleDependency(realPath, &alreadyAddedModules);
  }

  auto fileName = sf.getFilename();
  if (fileName.empty())
    return;

  switch (getKind()) {
  case swift::ModuleDependenciesKind::SwiftInterface: {
    // If the storage is for an interface file, the only source file we
    // should see is that interface file.
    auto swiftInterfaceStorage =
        cast<SwiftInterfaceModuleDependenciesStorage>(storage.get());
    assert(fileName == swiftInterfaceStorage->swiftInterfaceFile);
    break;
  }
  case swift::ModuleDependenciesKind::SwiftSource: {
    // Otherwise, record the source file.
    auto swiftSourceStorage =
        cast<SwiftSourceModuleDependenciesStorage>(storage.get());
    swiftSourceStorage->sourceFiles.push_back(fileName.str());
    break;
  }
  default:
    llvm_unreachable("Unexpected dependency kind");
  }
}

Optional<std::string> ModuleDependencies::getBridgingHeader() const {
  switch (getKind()) {
  case swift::ModuleDependenciesKind::SwiftInterface: {
    auto swiftInterfaceStorage =
        cast<SwiftInterfaceModuleDependenciesStorage>(storage.get());
    return swiftInterfaceStorage->textualModuleDetails.bridgingHeaderFile;
  }
  case swift::ModuleDependenciesKind::SwiftSource: {
    auto swiftSourceStorage =
        cast<SwiftSourceModuleDependenciesStorage>(storage.get());
    return swiftSourceStorage->textualModuleDetails.bridgingHeaderFile;
  }
  default:
    llvm_unreachable("Unexpected dependency kind");
  }
}

void ModuleDependencies::addBridgingHeader(StringRef bridgingHeader) {
  switch (getKind()) {
  case swift::ModuleDependenciesKind::SwiftInterface: {
    auto swiftInterfaceStorage =
        cast<SwiftInterfaceModuleDependenciesStorage>(storage.get());
    assert(!swiftInterfaceStorage->textualModuleDetails.bridgingHeaderFile);
    swiftInterfaceStorage->textualModuleDetails.bridgingHeaderFile = bridgingHeader.str();
    break;
  }
  case swift::ModuleDependenciesKind::SwiftSource: {
    auto swiftSourceStorage =
        cast<SwiftSourceModuleDependenciesStorage>(storage.get());
    assert(!swiftSourceStorage->textualModuleDetails.bridgingHeaderFile);
    swiftSourceStorage->textualModuleDetails.bridgingHeaderFile = bridgingHeader.str();
    break;
  }
  default:
    llvm_unreachable("Unexpected dependency kind");
  }
}

/// Add source files that the bridging header depends on.
void ModuleDependencies::addBridgingSourceFile(StringRef bridgingSourceFile) {
  switch (getKind()) {
  case swift::ModuleDependenciesKind::SwiftInterface: {
    auto swiftInterfaceStorage =
        cast<SwiftInterfaceModuleDependenciesStorage>(storage.get());
    swiftInterfaceStorage->textualModuleDetails.bridgingSourceFiles.push_back(
        bridgingSourceFile.str());
    break;
  }
  case swift::ModuleDependenciesKind::SwiftSource: {
    auto swiftSourceStorage =
        cast<SwiftSourceModuleDependenciesStorage>(storage.get());
    swiftSourceStorage->textualModuleDetails.bridgingSourceFiles.push_back(bridgingSourceFile.str());
    break;
  }
  default:
    llvm_unreachable("Unexpected dependency kind");
  }
}

void ModuleDependencies::addSourceFile(StringRef sourceFile) {
  switch (getKind()) {
  case swift::ModuleDependenciesKind::SwiftSource: {
    auto swiftSourceStorage =
        cast<SwiftSourceModuleDependenciesStorage>(storage.get());
    swiftSourceStorage->sourceFiles.push_back(sourceFile.str());
    break;
  }
  default:
    llvm_unreachable("Unexpected dependency kind");
  }
}

/// Add (Clang) module on which the bridging header depends.
void ModuleDependencies::addBridgingModuleDependency(
    StringRef module, llvm::StringSet<> &alreadyAddedModules) {
  switch (getKind()) {
  case swift::ModuleDependenciesKind::SwiftInterface: {
    auto swiftInterfaceStorage =
        cast<SwiftInterfaceModuleDependenciesStorage>(storage.get());
    if (alreadyAddedModules.insert(module).second)
      swiftInterfaceStorage->textualModuleDetails.bridgingModuleDependencies.push_back(module.str());
    break;
  }
  case swift::ModuleDependenciesKind::SwiftSource: {
    auto swiftSourceStorage =
        cast<SwiftSourceModuleDependenciesStorage>(storage.get());
    if (alreadyAddedModules.insert(module).second)
      swiftSourceStorage->textualModuleDetails.bridgingModuleDependencies.push_back(module.str());
    break;
  }
  default:
    llvm_unreachable("Unexpected dependency kind");
  }
}

GlobalModuleDependenciesCache::GlobalModuleDependenciesCache()
  : ClangScanningService(clang::tooling::dependencies::ScanningMode::DependencyDirectivesScan,
                         clang::tooling::dependencies::ScanningOutputFormat::Full,
                         clang::CASOptions(),
                         /* Cache (llvm::cas::ActionCache) */ nullptr,
                         /* SharedFS */ nullptr,
                         /* ReuseFileManager */ false,
                         /* OptimizeArgs */ false) {
    SharedFilesystemCache.emplace();
}

void GlobalModuleDependenciesCache::overlaySharedFilesystemCacheForCompilation(CompilerInstance &Instance) {
 auto existingFS = Instance.getSourceMgr().getFileSystem();
 llvm::IntrusiveRefCntPtr<
     clang::tooling::dependencies::DependencyScanningWorkerFilesystem>
     depFS =
         new clang::tooling::dependencies::DependencyScanningWorkerFilesystem(
             getSharedFilesystemCache(), existingFS);
 Instance.getSourceMgr().setFileSystem(depFS);
}

GlobalModuleDependenciesCache::ContextSpecificGlobalCacheState *
GlobalModuleDependenciesCache::getCurrentCache() const {
  assert(CurrentContextHash.has_value() &&
         "Global Module Dependencies Cache not configured with Triple.");
  return getCacheForScanningContextHash(CurrentContextHash.value());
}

GlobalModuleDependenciesCache::ContextSpecificGlobalCacheState *
GlobalModuleDependenciesCache::getCacheForScanningContextHash(StringRef scanningContextHash) const {
  auto contextSpecificCache = ContextSpecificCacheMap.find(scanningContextHash);
  assert(contextSpecificCache != ContextSpecificCacheMap.end() &&
         "Global Module Dependencies Cache not configured with context-specific "
         "state.");
  return contextSpecificCache->getValue().get();
}

const ModuleNameToDependencyMap &
GlobalModuleDependenciesCache::getDependenciesMap(
    ModuleDependenciesKind kind) const {
  auto contextSpecificCache = getCurrentCache();
  auto it = contextSpecificCache->ModuleDependenciesMap.find(kind);
  assert(it != contextSpecificCache->ModuleDependenciesMap.end() &&
         "invalid dependency kind");
  return it->second;
}

ModuleNameToDependencyMap &
GlobalModuleDependenciesCache::getDependenciesMap(
    ModuleDependenciesKind kind) {
  auto contextSpecificCache = getCurrentCache();
  auto it = contextSpecificCache->ModuleDependenciesMap.find(kind);
  assert(it != contextSpecificCache->ModuleDependenciesMap.end() &&
         "invalid dependency kind");
  return it->second;
}

void GlobalModuleDependenciesCache::configureForContextHash(std::string scanningContextHash) {
  auto knownContext = ContextSpecificCacheMap.find(scanningContextHash);
  if (knownContext != ContextSpecificCacheMap.end()) {
    // Set the current context and leave the rest as-is
    CurrentContextHash = scanningContextHash;
  } else {
    // First time scanning with this triple, initialize target-specific state.
    std::unique_ptr<ContextSpecificGlobalCacheState> contextSpecificCache =
        std::make_unique<ContextSpecificGlobalCacheState>();
    for (auto kind = ModuleDependenciesKind::FirstKind;
         kind != ModuleDependenciesKind::LastKind; ++kind) {
      contextSpecificCache->ModuleDependenciesMap.insert({kind, ModuleNameToDependencyMap()});
    }

    ContextSpecificCacheMap.insert({scanningContextHash, std::move(contextSpecificCache)});
    CurrentContextHash = scanningContextHash;
    AllContextHashes.push_back(scanningContextHash);
  }
}

Optional<ModuleDependencies> GlobalModuleDependenciesCache::findDependencies(
    StringRef moduleName, Optional<ModuleDependenciesKind> kind) const {
  if (!kind) {
    for (auto kind = ModuleDependenciesKind::FirstKind;
         kind != ModuleDependenciesKind::LastKind; ++kind) {
      auto dep = findDependencies(moduleName, kind);
      if (dep.has_value())
        return dep.value();
    }
    return None;
  }

  assert(kind.has_value() && "Expected dependencies kind for lookup.");
  if (kind.value() == swift::ModuleDependenciesKind::SwiftSource) {
    return findSourceModuleDependency(moduleName);
  }

  const auto &map = getDependenciesMap(kind.value());
  auto known = map.find(moduleName);
  if (known != map.end())
    return known->second;

  return None;
}

Optional<ModuleDependencies>
GlobalModuleDependenciesCache::findSourceModuleDependency(
    StringRef moduleName) const {
  auto known = SwiftSourceModuleDependenciesMap.find(moduleName);
  if (known != SwiftSourceModuleDependenciesMap.end())
    return known->second;
  else
    return None;
}

bool GlobalModuleDependenciesCache::hasDependencies(
    StringRef moduleName, Optional<ModuleDependenciesKind> kind) const {
  assert(kind != ModuleDependenciesKind::Clang &&
         "Attempting to query Clang dependency in persistent Dependency "
         "Scanner Cache.");
  return findDependencies(moduleName, kind).has_value();
}

static std::string modulePathForVerification(const ModuleDependencies &module) {
  std::string existingModulePath = "";
  switch (module.getKind()) {
  case swift::ModuleDependenciesKind::SwiftInterface: {
    auto *swiftDep = module.getAsSwiftInterfaceModule();
    existingModulePath = swiftDep->swiftInterfaceFile;
    break;
  }
  case swift::ModuleDependenciesKind::SwiftBinary: {
    auto *swiftBinaryDep = module.getAsSwiftBinaryModule();
    existingModulePath = swiftBinaryDep->compiledModulePath;
    break;
  }
  case swift::ModuleDependenciesKind::Clang: {
    auto *clangDep = module.getAsClangModule();
    existingModulePath = clangDep->moduleMapFile;
    break;
  }
  case swift::ModuleDependenciesKind::SwiftSource:
  case swift::ModuleDependenciesKind::SwiftPlaceholder:
  case swift::ModuleDependenciesKind::LastKind:
    llvm_unreachable("Unhandled dependency kind.");
  }
  return existingModulePath;
}

const ModuleDependencies *GlobalModuleDependenciesCache::recordDependencies(
    StringRef moduleName, ModuleDependencies dependencies) {
  auto kind = dependencies.getKind();
  assert(kind != ModuleDependenciesKind::Clang &&
         "Attempting to cache Clang dependency in persistent Dependency "
         "Scanner Cache.");

  // Source-based dependencies are recorded independently of the invocation's
  // target triple.
  if (kind == swift::ModuleDependenciesKind::SwiftSource) {
    assert(SwiftSourceModuleDependenciesMap.count(moduleName) == 0 &&
           "Attempting to record duplicate SwiftSource dependency.");
    SwiftSourceModuleDependenciesMap.insert(
        {moduleName, std::move(dependencies)});
    AllSourceModules.push_back({moduleName.str(), kind});
    return &(SwiftSourceModuleDependenciesMap.find(moduleName)->second);
  }

  // All other dependencies are recorded according to the target triple of the
  // scanning invocation that discovers them.
  auto &map = getDependenciesMap(kind);
  map.insert({moduleName, dependencies});
  return &(map[moduleName]);
}

const ModuleDependencies *GlobalModuleDependenciesCache::updateDependencies(
    ModuleDependencyID moduleID, ModuleDependencies dependencies) {
  auto kind = dependencies.getKind();
  assert(kind != ModuleDependenciesKind::Clang &&
         "Attempting to update Clang dependency in persistent Dependency "
         "Scanner Cache.");

  // Source-based dependencies
  if (kind == swift::ModuleDependenciesKind::SwiftSource) {
    assert(SwiftSourceModuleDependenciesMap.count(moduleID.first) == 1 &&
           "Attempting to update non-existing Swift Source dependency.");
    auto known = SwiftSourceModuleDependenciesMap.find(moduleID.first);
    known->second = std::move(dependencies);
    return &(known->second);
  }

  auto &map = getDependenciesMap(moduleID.second);
  auto known = map.find(moduleID.first);
  assert(known != map.end() && "Not yet added to map");
  known->second = std::move(dependencies);
  return &(known->second);
}

llvm::StringMap<const ModuleDependencies *> &
ModuleDependenciesCache::getDependencyReferencesMap(
    ModuleDependenciesKind kind) {
  auto it = ModuleDependenciesMap.find(kind);
  assert(it != ModuleDependenciesMap.end() && "invalid dependency kind");
  return it->second;
}

const llvm::StringMap<const ModuleDependencies *> &
ModuleDependenciesCache::getDependencyReferencesMap(
    ModuleDependenciesKind kind) const {
  auto it = ModuleDependenciesMap.find(kind);
  assert(it != ModuleDependenciesMap.end() && "invalid dependency kind");
  return it->second;
}

ModuleDependenciesCache::ModuleDependenciesCache(
    GlobalModuleDependenciesCache &globalCache,
    std::string mainScanModuleName,
    std::string scannerContextHash)
    : globalCache(globalCache),
      mainScanModuleName(mainScanModuleName),
      scannerContextHash(scannerContextHash),
      clangScanningTool(globalCache.ClangScanningService) {
  globalCache.configureForContextHash(scannerContextHash);
  for (auto kind = ModuleDependenciesKind::FirstKind;
       kind != ModuleDependenciesKind::LastKind; ++kind) {
    ModuleDependenciesMap.insert(
        {kind, llvm::StringMap<const ModuleDependencies *>()});
  }
}

Optional<const ModuleDependencies *> ModuleDependenciesCache::findDependenciesLocalOnly(
    StringRef moduleName, Optional<ModuleDependenciesKind> kind) const {
  if (!kind) {
    for (auto kind = ModuleDependenciesKind::FirstKind;
         kind != ModuleDependenciesKind::LastKind; ++kind) {
      auto dep = findDependenciesLocalOnly(moduleName, kind);
      if (dep.has_value())
        return dep.value();
    }
    return None;
  }

  const auto &map = getDependencyReferencesMap(*kind);
  auto known = map.find(moduleName);
  if (known != map.end())
    return known->second;

  return None;
}

Optional<ModuleDependencies>
ModuleDependenciesCache::findDependencies(
    StringRef moduleName, Optional<ModuleDependenciesKind> kind) const {
  // 1. Query the local scan results
  // 2. If no module found, query the global cache
  auto localResult = findDependenciesLocalOnly(moduleName, kind);
  if (localResult.has_value())
    return *(localResult.value());
  else
    return globalCache.findDependencies(moduleName, kind);
}

bool ModuleDependenciesCache::hasDependenciesLocalOnly(StringRef moduleName,
                                                       Optional<ModuleDependenciesKind> kind) const {
  return findDependenciesLocalOnly(moduleName, kind).has_value();
}

bool ModuleDependenciesCache::hasDependencies(
    StringRef moduleName, Optional<ModuleDependenciesKind> kind) const {
  return findDependencies(moduleName, kind).has_value();
}

void ModuleDependenciesCache::recordDependencies(
    StringRef moduleName, ModuleDependencies dependencies) {
  auto dependenciesKind = dependencies.getKind();

  // The underlying Clang module needs to be cached in this invocation,
  // but should not make it to the global cache since it will look slightly
  // differently for clients of this module than it does for the module itself.
  const ModuleDependencies *recordedDependencies;
  if (dependencies.getKind() == ModuleDependenciesKind::Clang) {
    auto *clangDep = dependencies.getAsClangModule();
    assert(clangDep && "Unexpected NULL Clang dependency.");
    // Cache may already have a dependency for this module
    if (clangModuleDependencies.count(moduleName) != 0) {
      // Do not record duplicate dependencies.
      auto newModulePath = clangDep->moduleMapFile;
      for (auto &existingDeps : clangModuleDependencies[moduleName]) {
        if (modulePathForVerification(existingDeps) == newModulePath)
          return;
      }
      clangModuleDependencies[moduleName].emplace_back(std::move(dependencies));
      recordedDependencies = clangModuleDependencies[moduleName].end() - 1;
    } else {
      clangModuleDependencies.insert(
          {moduleName, ModuleDependenciesVector{std::move(dependencies)}});
      recordedDependencies = &(clangModuleDependencies[moduleName].front());
    }

  } else
    recordedDependencies =
        globalCache.recordDependencies(moduleName, dependencies);

  auto &map = getDependencyReferencesMap(dependenciesKind);
  assert(map.count(moduleName) == 0 && "Already added to map");
  map.insert({moduleName, recordedDependencies});
}

void ModuleDependenciesCache::updateDependencies(
    ModuleDependencyID moduleID, ModuleDependencies dependencies) {
  auto globalDepRef = globalCache.updateDependencies(moduleID, dependencies);
  auto &map = getDependencyReferencesMap(moduleID.second);
  auto known = map.find(moduleID.first);
  if (known != map.end())
    map.erase(known);
  map.insert({moduleID.first, globalDepRef});
}