/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying

   file LICENSE.rst or https://cmake.org/licensing for details.  */

#include "cmBinUtilsMacOSMachOLinker.h"

#include <sstream>

#include <string>

#include <utility>

#include <vector>

#include <cm/memory>

#include "cmBinUtilsMacOSMachOOToolGetRuntimeDependenciesTool.h"

#include "cmRuntimeDependencyArchive.h"

#include "cmStringAlgorithms.h"

#include "cmSystemTools.h"

namespace {

bool IsMissingSystemDylib(std::string const& path)

{

  // Starting on macOS 11, the dynamic loader has a builtin cache of

  // system-provided dylib files that do not exist on the filesystem.

  // Tell our caller that these are expected to be missing.

  return ((cmHasLiteralPrefix(path, "/System/Library/") ||

           cmHasLiteralPrefix(path, "/usr/lib/")) &&

          !cmSystemTools::PathExists(path));

}

}

cmBinUtilsMacOSMachOLinker::cmBinUtilsMacOSMachOLinker(

  cmRuntimeDependencyArchive* archive)

  : cmBinUtilsLinker(archive)

{

}

bool cmBinUtilsMacOSMachOLinker::Prepare()

{

  std::string tool = this->Archive->GetGetRuntimeDependenciesTool();

  if (tool.empty()) {

    tool = "otool";

  }

  if (tool == "otool") {

    this->Tool =

      cm::make_unique<cmBinUtilsMacOSMachOOToolGetRuntimeDependenciesTool>(

        this->Archive);

  } else {

    std::ostringstream e;

    e << "Invalid value for CMAKE_GET_RUNTIME_DEPENDENCIES_TOOL: " << tool;

    this->SetError(e.str());

    return false;

  }

  return true;

}

auto cmBinUtilsMacOSMachOLinker::GetFileInfo(std::string const& file)

  -> FileInfo const*

{

  // Memoize processed rpaths and library dependencies to reduce the number

  // of calls to otool, especially in the case of heavily recursive libraries

  auto iter = ScannedFileInfo.find(file);

  if (iter != ScannedFileInfo.end()) {

    return &iter->second;

  }

  FileInfo file_info;

  if (!this->Tool->GetFileInfo(file, file_info.libs, file_info.rpaths)) {

    // Call to otool failed

    return nullptr;

  }

  auto iter_inserted = ScannedFileInfo.insert({ file, std::move(file_info) });

  return &iter_inserted.first->second;

}

bool cmBinUtilsMacOSMachOLinker::ScanDependencies(

  std::string const& file, cmStateEnums::TargetType type)

{

  std::string executableFile;

  if (type == cmStateEnums::EXECUTABLE) {

    executableFile = file;

  } else {

    executableFile = this->Archive->GetBundleExecutable();

  }

  std::string executablePath;

  if (!executableFile.empty()) {

    executablePath = cmSystemTools::GetFilenamePath(executableFile);

  }

  FileInfo const* file_info = this->GetFileInfo(file);

  if (!file_info) {

    return false;

  }

  return this->ScanDependencies(file, file_info->libs, file_info->rpaths,

                                executablePath);

}

bool cmBinUtilsMacOSMachOLinker::ScanDependencies(

  std::string const& file, std::vector<std::string> const& libs,

  std::vector<std::string> const& rpaths, std::string const& executablePath)

{

  std::string loaderPath = cmSystemTools::GetFilenamePath(file);

  return this->GetFileDependencies(libs, executablePath, loaderPath, rpaths);

}

bool cmBinUtilsMacOSMachOLinker::GetFileDependencies(

  std::vector<std::string> const& names, std::string const& executablePath,

  std::string const& loaderPath, std::vector<std::string> const& rpaths)

{

  for (std::string const& name : names) {

    if (!this->Archive->IsPreExcluded(name)) {

      std::string path;

      bool resolved;

      if (!this->ResolveDependency(name, executablePath, loaderPath, rpaths,

                                   path, resolved)) {

        return false;

      }

      if (resolved) {

        if (!this->Archive->IsPostExcluded(path) &&

            !IsMissingSystemDylib(path)) {

          auto filename = cmSystemTools::GetFilenameName(path);

          bool unique;

          FileInfo const* dep_file_info = this->GetFileInfo(path);

          if (!dep_file_info) {

            return false;

          }

          this->Archive->AddResolvedPath(filename, path, unique,

                                         dep_file_info->rpaths);

          if (unique) {

            std::vector<std::string> combinedParentRpaths =

              dep_file_info->rpaths;

            combinedParentRpaths.insert(combinedParentRpaths.end(),

                                        rpaths.begin(), rpaths.end());

            if (!this->ScanDependencies(path, dep_file_info->libs,

                                        combinedParentRpaths,

                                        executablePath)) {

              return false;

            }

          }

        }

      } else {

        this->Archive->AddUnresolvedPath(name);

      }

    }

  }

  return true;

}

bool cmBinUtilsMacOSMachOLinker::ResolveDependency(

  std::string const& name, std::string const& executablePath,

  std::string const& loaderPath, std::vector<std::string> const& rpaths,

  std::string& path, bool& resolved)

{

  resolved = false;

  if (cmHasLiteralPrefix(name, "@rpath/")) {

    if (!this->ResolveRPathDependency(name, executablePath, loaderPath, rpaths,

                                      path, resolved)) {

      return false;

    }

  } else if (cmHasLiteralPrefix(name, "@loader_path/")) {

    if (!this->ResolveLoaderPathDependency(name, loaderPath, path, resolved)) {

      return false;

    }

  } else if (cmHasLiteralPrefix(name, "@executable_path/")) {

    if (!this->ResolveExecutablePathDependency(name, executablePath, path,

                                               resolved)) {

      return false;

    }

  } else {

    resolved = true;

    path = name;

    this->NormalizePath(path);

  }

  if (resolved && !cmSystemTools::FileIsFullPath(path)) {

    this->SetError("Resolved path is not absolute");

    return false;

  }

  return true;

}

bool cmBinUtilsMacOSMachOLinker::ResolveExecutablePathDependency(

  std::string const& name, std::string const& executablePath,

  std::string& path, bool& resolved)

{

  if (executablePath.empty()) {

    resolved = false;

    return true;

  }

  // 16 is == "@executable_path".length()

  path = name;

  path.replace(0, 16, executablePath);

  if (!cmSystemTools::PathExists(path)) {

    resolved = false;

    return true;

  }

  this->NormalizePath(path);

  resolved = true;

  return true;

}

bool cmBinUtilsMacOSMachOLinker::ResolveLoaderPathDependency(

  std::string const& name, std::string const& loaderPath, std::string& path,

  bool& resolved)

{

  if (loaderPath.empty()) {

    resolved = false;

    return true;

  }

  // 12 is "@loader_path".length();

  path = name;

  path.replace(0, 12, loaderPath);

  if (!cmSystemTools::PathExists(path)) {

    resolved = false;

    return true;

  }

  this->NormalizePath(path);

  resolved = true;

  return true;

}

bool cmBinUtilsMacOSMachOLinker::ResolveRPathDependency(

  std::string const& name, std::string const& executablePath,

  std::string const& loaderPath, std::vector<std::string> const& rpaths,

  std::string& path, bool& resolved)

{

  for (std::string const& rpath : rpaths) {

    std::string searchFile = name;

    searchFile.replace(0, 6, rpath);

    if (cmHasLiteralPrefix(searchFile, "@loader_path/")) {

      if (!this->ResolveLoaderPathDependency(searchFile, loaderPath, path,

                                             resolved)) {

        return false;

      }

      if (resolved) {

        return true;

      }

    } else if (cmHasLiteralPrefix(searchFile, "@executable_path/")) {

      if (!this->ResolveExecutablePathDependency(searchFile, executablePath,

                                                 path, resolved)) {

        return false;

      }

      if (resolved) {

        return true;

      }

    } else if (cmSystemTools::PathExists(searchFile)) {

      /*

       * paraphrasing @ben.boeckel:

       *  if /b/libB.dylib is supposed to be used,

       *  /a/libB.dylib will be found first if it exists. CMake tries to

       *  sort rpath directories to avoid this, but sometimes there is no

       *  right answer.

       *

       *  I believe it is possible to resolve this using otools -l

       *  then checking the LC_LOAD_DYLIB command whose name is

       *  equal to the value of search_file, UNLESS the build

       *  specifically sets the RPath to paths that will match

       *  duplicate libs; at this point can we just point to

       *  user error, or is there a reason why the advantages

       *  to this scenario outweigh its disadvantages?

       *

       *  Also priority seems to be the order as passed in when compiled

       *  so as long as this method's resolution guarantees priority

       *  in that manner further checking should not be necessary?

       */

      path = std::move(searchFile);

      this->NormalizePath(path);

      resolved = true;

      return true;

    }

  }

  resolved = false;

  return true;

}