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

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

#include "cmTargetLinkLibrariesCommand.h"

#include <cassert>

#include <cstddef>

#include <memory>

#include <sstream>

#include <unordered_set>

#include <utility>

#include <cm/optional>

#include <cm/string_view>

#include "cmExecutionStatus.h"

#include "cmGeneratorExpression.h"

#include "cmGlobalGenerator.h"

#include "cmListFileCache.h"

#include "cmMakefile.h"

#include "cmMessageType.h"

#include "cmPolicies.h"

#include "cmState.h"

#include "cmStateTypes.h"

#include "cmStringAlgorithms.h"

#include "cmSystemTools.h"

#include "cmTarget.h"

#include "cmTargetLinkLibraryType.h"

namespace {

enum ProcessingState

{

  ProcessingLinkLibraries,

  ProcessingPlainLinkInterface,

  ProcessingKeywordLinkInterface,

  ProcessingPlainPublicInterface,

  ProcessingKeywordPublicInterface,

  ProcessingPlainPrivateInterface,

  ProcessingKeywordPrivateInterface

};

char const* LinkLibraryTypeNames[3] = { "general", "debug", "optimized" };

struct TLL

{

  cmMakefile& Makefile;

  cmTarget* Target;

  bool WarnRemoteInterface = false;

  bool RejectRemoteLinking = false;

  bool EncodeRemoteReference = false;

  std::string DirectoryId;

  std::unordered_set<std::string> Props;

  TLL(cmMakefile& mf, cmTarget* target);

  ~TLL();

  bool HandleLibrary(ProcessingState currentProcessingState,

                     std::string const& lib, cmTargetLinkLibraryType llt);

  void AppendProperty(std::string const& prop, std::string const& value);

  void AffectsProperty(std::string const& prop);

};

} // namespace

static void LinkLibraryTypeSpecifierWarning(cmMakefile& mf, int left,

                                            int right);

bool cmTargetLinkLibrariesCommand(std::vector<std::string> const& args,

                                  cmExecutionStatus& status)

{

  // Must have at least one argument.

  if (args.empty()) {

    status.SetError("called with incorrect number of arguments");

    return false;

  }

  cmMakefile& mf = status.GetMakefile();

  // Alias targets cannot be on the LHS of this command.

  if (mf.IsAlias(args[0])) {

    status.SetError("can not be used on an ALIAS target.");

    return false;

  }

  // Lookup the target for which libraries are specified.

  cmTarget* target = mf.GetGlobalGenerator()->FindTarget(args[0]);

  if (!target) {

    for (auto const& importedTarget : mf.GetOwnedImportedTargets()) {

      if (importedTarget->GetName() == args[0] &&

          !importedTarget->IsForeign()) {

        target = importedTarget.get();

        break;

      }

    }

  }

  if (!target) {

    mf.IssueMessage(MessageType::FATAL_ERROR,

                    cmStrCat("Cannot specify link libraries for target \"",

                             args[0],

                             "\" which is not built by this project."));

    cmSystemTools::SetFatalErrorOccurred();

    return true;

  }

  if (target->IsSymbolic()) {

    status.SetError("can not be used on a SYMBOLIC target.");

    return false;

  }

  // Having a UTILITY library on the LHS is a bug.

  if (target->GetType() == cmStateEnums::UTILITY) {

    mf.IssueMessage(

      MessageType::FATAL_ERROR,

      cmStrCat(

        "Utility target \"", target->GetName(),

        "\" must not be used as the target of a target_link_libraries call."));

    return false;

  }

  // But we might not have any libs after variable expansion.

  if (args.size() < 2) {

    return true;

  }

  TLL tll(mf, target);

  // Keep track of link configuration specifiers.

  cmTargetLinkLibraryType llt = GENERAL_LibraryType;

  bool haveLLT = false;

  // Start with primary linking and switch to link interface

  // specification if the keyword is encountered as the first argument.

  ProcessingState currentProcessingState = ProcessingLinkLibraries;

  // Accumulate consecutive non-keyword arguments into one entry in

  // order to handle unquoted generator expressions containing ';'.

  std::size_t genexNesting = 0;

  cm::optional<std::string> currentEntry;

  auto processCurrentEntry = [&]() -> bool {

    // FIXME: Warn about partial genex if genexNesting > 0?

    genexNesting = 0;

    if (currentEntry) {

      assert(!haveLLT);

      if (!tll.HandleLibrary(currentProcessingState, *currentEntry,

                             GENERAL_LibraryType)) {

        return false;

      }

      currentEntry = cm::nullopt;

    }

    return true;

  };

  auto extendCurrentEntry = [&currentEntry](std::string const& arg) {

    if (currentEntry) {

      currentEntry = cmStrCat(*currentEntry, ';', arg);

    } else {

      currentEntry = arg;

    }

  };

  // Keep this list in sync with the keyword dispatch below.

  static std::unordered_set<std::string> const keywords{

    "LINK_INTERFACE_LIBRARIES",

    "INTERFACE",

    "LINK_PUBLIC",

    "PUBLIC",

    "LINK_PRIVATE",

    "PRIVATE",

    "debug",

    "optimized",

    "general",

  };

  // Add libraries, note that there is an optional prefix

  // of debug and optimized that can be used.

  for (unsigned int i = 1; i < args.size(); ++i) {

    if (keywords.count(args[i])) {

      // A keyword argument terminates any accumulated partial genex.

      if (!processCurrentEntry()) {

        return false;

      }

      // Process this keyword argument.

      if (args[i] == "LINK_INTERFACE_LIBRARIES") {

        currentProcessingState = ProcessingPlainLinkInterface;

        if (i != 1) {

          mf.IssueMessage(

            MessageType::FATAL_ERROR,

            "The LINK_INTERFACE_LIBRARIES option must appear as the "

            "second argument, just after the target name.");

          return true;

        }

      } else if (args[i] == "INTERFACE") {

        if (i != 1 &&

            currentProcessingState != ProcessingKeywordPrivateInterface &&

            currentProcessingState != ProcessingKeywordPublicInterface &&

            currentProcessingState != ProcessingKeywordLinkInterface) {

          mf.IssueMessage(MessageType::FATAL_ERROR,

                          "The INTERFACE, PUBLIC or PRIVATE option must "

                          "appear as the second argument, just after the "

                          "target name.");

          return true;

        }

        currentProcessingState = ProcessingKeywordLinkInterface;

      } else if (args[i] == "LINK_PUBLIC") {

        if (i != 1 &&

            currentProcessingState != ProcessingPlainPrivateInterface &&

            currentProcessingState != ProcessingPlainPublicInterface) {

          mf.IssueMessage(

            MessageType::FATAL_ERROR,

            "The LINK_PUBLIC or LINK_PRIVATE option must appear as the "

            "second argument, just after the target name.");

          return true;

        }

        currentProcessingState = ProcessingPlainPublicInterface;

      } else if (args[i] == "PUBLIC") {

        if (i != 1 &&

            currentProcessingState != ProcessingKeywordPrivateInterface &&

            currentProcessingState != ProcessingKeywordPublicInterface &&

            currentProcessingState != ProcessingKeywordLinkInterface) {

          mf.IssueMessage(MessageType::FATAL_ERROR,

                          "The INTERFACE, PUBLIC or PRIVATE option must "

                          "appear as the second argument, just after the "

                          "target name.");

          return true;

        }

        currentProcessingState = ProcessingKeywordPublicInterface;

      } else if (args[i] == "LINK_PRIVATE") {

        if (i != 1 &&

            currentProcessingState != ProcessingPlainPublicInterface &&

            currentProcessingState != ProcessingPlainPrivateInterface) {

          mf.IssueMessage(

            MessageType::FATAL_ERROR,

            "The LINK_PUBLIC or LINK_PRIVATE option must appear as the "

            "second argument, just after the target name.");

          return true;

        }

        currentProcessingState = ProcessingPlainPrivateInterface;

      } else if (args[i] == "PRIVATE") {

        if (i != 1 &&

            currentProcessingState != ProcessingKeywordPrivateInterface &&

            currentProcessingState != ProcessingKeywordPublicInterface &&

            currentProcessingState != ProcessingKeywordLinkInterface) {

          mf.IssueMessage(MessageType::FATAL_ERROR,

                          "The INTERFACE, PUBLIC or PRIVATE option must "

                          "appear as the second argument, just after the "

                          "target name.");

          return true;

        }

        currentProcessingState = ProcessingKeywordPrivateInterface;

      } else if (args[i] == "debug") {

        if (haveLLT) {

          LinkLibraryTypeSpecifierWarning(mf, llt, DEBUG_LibraryType);

        }

        llt = DEBUG_LibraryType;

        haveLLT = true;

      } else if (args[i] == "optimized") {

        if (haveLLT) {

          LinkLibraryTypeSpecifierWarning(mf, llt, OPTIMIZED_LibraryType);

        }

        llt = OPTIMIZED_LibraryType;

        haveLLT = true;

      } else if (args[i] == "general") {

        if (haveLLT) {

          LinkLibraryTypeSpecifierWarning(mf, llt, GENERAL_LibraryType);

        }

        llt = GENERAL_LibraryType;

        haveLLT = true;

      }

    } else if (haveLLT) {

      // The link type was specified by the previous argument.

      haveLLT = false;

      assert(!currentEntry);

      if (!tll.HandleLibrary(currentProcessingState, args[i], llt)) {

        return false;

      }

      llt = GENERAL_LibraryType;

    } else {

      // Track the genex nesting level.

      {

        cm::string_view arg = args[i];

        for (std::string::size_type pos = 0; pos < arg.size(); ++pos) {

          cm::string_view cur = arg.substr(pos);

          if (cmHasLiteralPrefix(cur, "$<")) {

            ++genexNesting;

            ++pos;

          } else if (genexNesting > 0 && cmHasPrefix(cur, '>')) {

            --genexNesting;

          }

        }

      }

      // Accumulate this argument in the current entry.

      extendCurrentEntry(args[i]);

      // Process this entry if it does not end inside a genex.

      if (genexNesting == 0) {

        if (!processCurrentEntry()) {

          return false;

        }

      }

    }

  }

  // Process the last accumulated partial genex, if any.

  if (!processCurrentEntry()) {

    return false;

  }

  // Make sure the last argument was not a library type specifier.

  if (haveLLT) {

    mf.IssueMessage(MessageType::FATAL_ERROR,

                    cmStrCat("The \"", LinkLibraryTypeNames[llt],

                             "\" argument must be followed by a library."));

    cmSystemTools::SetFatalErrorOccurred();

  }

  return true;

}

static void LinkLibraryTypeSpecifierWarning(cmMakefile& mf, int left,

                                            int right)

{

  mf.IssueMessage(

    MessageType::AUTHOR_WARNING,

    cmStrCat(

      "Link library type specifier \"", LinkLibraryTypeNames[left],

      "\" is followed by specifier \"", LinkLibraryTypeNames[right],

      "\" instead of a library name.  The first specifier will be ignored."));

}

namespace {

TLL::TLL(cmMakefile& mf, cmTarget* target)

  : Makefile(mf)

  , Target(target)

{

  if (&this->Makefile != this->Target->GetMakefile()) {

    // The LHS target was created in another directory.

    switch (this->Makefile.GetPolicyStatus(cmPolicies::CMP0079)) {

      case cmPolicies::WARN:

        this->WarnRemoteInterface = true;

        CM_FALLTHROUGH;

      case cmPolicies::OLD:

        this->RejectRemoteLinking = true;

        break;

      case cmPolicies::NEW:

        this->EncodeRemoteReference = true;

        break;

    }

  }

  if (this->EncodeRemoteReference) {

    cmDirectoryId const dirId = this->Makefile.GetDirectoryId();

    this->DirectoryId = cmStrCat(CMAKE_DIRECTORY_ID_SEP, dirId.String);

  }

}

bool TLL::HandleLibrary(ProcessingState currentProcessingState,

                        std::string const& lib, cmTargetLinkLibraryType llt)

{

  if (this->Target->GetType() == cmStateEnums::INTERFACE_LIBRARY &&

      currentProcessingState != ProcessingKeywordLinkInterface) {

    this->Makefile.IssueMessage(

      MessageType::FATAL_ERROR,

      "INTERFACE library can only be used with the INTERFACE keyword of "

      "target_link_libraries");

    return false;

  }

  if (this->Target->IsImported() &&

      currentProcessingState != ProcessingKeywordLinkInterface) {

    this->Makefile.IssueMessage(

      MessageType::FATAL_ERROR,

      "IMPORTED library can only be used with the INTERFACE keyword of "

      "target_link_libraries");

    return false;

  }

  cmTarget::TLLSignature sig =

    (currentProcessingState == ProcessingPlainPrivateInterface ||

     currentProcessingState == ProcessingPlainPublicInterface ||

     currentProcessingState == ProcessingKeywordPrivateInterface ||

     currentProcessingState == ProcessingKeywordPublicInterface ||

     currentProcessingState == ProcessingKeywordLinkInterface)

    ? cmTarget::KeywordTLLSignature

    : cmTarget::PlainTLLSignature;

  if (!this->Target->PushTLLCommandTrace(

        sig, this->Makefile.GetBacktrace().Top())) {

    std::ostringstream e;

    // If the sig is a keyword form and there is a conflict, the existing

    // form must be the plain form.

    char const* existingSig =

      (sig == cmTarget::KeywordTLLSignature ? "plain" : "keyword");

    e << "The " << existingSig

      << " signature for target_link_libraries has "

         "already been used with the target \""

      << this->Target->GetName()

      << "\".  All uses of target_link_libraries with a target must "

      << " be either all-keyword or all-plain.\n";

    this->Target->GetTllSignatureTraces(e,

                                        sig == cmTarget::KeywordTLLSignature

                                          ? cmTarget::PlainTLLSignature

                                          : cmTarget::KeywordTLLSignature);

    this->Makefile.IssueMessage(MessageType::FATAL_ERROR, e.str());

    return false;

  }

  // Handle normal case where the command was called with another keyword than

  // INTERFACE / LINK_INTERFACE_LIBRARIES or none at all. (The "LINK_LIBRARIES"

  // property of the target on the LHS shall be populated.)

  if (currentProcessingState != ProcessingKeywordLinkInterface &&

      currentProcessingState != ProcessingPlainLinkInterface) {

    if (this->RejectRemoteLinking) {

      this->Makefile.IssueMessage(

        MessageType::FATAL_ERROR,

        cmStrCat("Attempt to add link library \"", lib, "\" to target \"",

                 this->Target->GetName(),

                 "\" which is not built in this "

                 "directory.\nThis is allowed only when policy CMP0079 "

                 "is set to NEW."));

      return false;

    }

    cmTarget* tgt = this->Makefile.GetGlobalGenerator()->FindTarget(lib);

    if (tgt && (tgt->GetType() != cmStateEnums::STATIC_LIBRARY) &&

        (tgt->GetType() != cmStateEnums::SHARED_LIBRARY) &&

        (tgt->GetType() != cmStateEnums::UNKNOWN_LIBRARY) &&

        (tgt->GetType() != cmStateEnums::OBJECT_LIBRARY) &&

        (tgt->GetType() != cmStateEnums::INTERFACE_LIBRARY) &&

        !tgt->IsExecutableWithExports()) {

      this->Makefile.IssueMessage(

        MessageType::FATAL_ERROR,

        cmStrCat(

          "Target \"", lib, "\" of type ",

          cmState::GetTargetTypeName(tgt->GetType()),

          " may not be linked into another target. One may link only to "

          "INTERFACE, OBJECT, STATIC or SHARED libraries, or to "

          "executables with the ENABLE_EXPORTS property set."));

    }

    this->AffectsProperty("LINK_LIBRARIES");

    this->Target->AddLinkLibrary(this->Makefile, lib, llt);

  }

  if (this->WarnRemoteInterface) {

    this->Makefile.IssueMessage(

      MessageType::AUTHOR_WARNING,

      cmStrCat(

        cmPolicies::GetPolicyWarning(cmPolicies::CMP0079), "\nTarget\n  ",

        this->Target->GetName(),

        "\nis not created in this "

        "directory.  For compatibility with older versions of CMake, link "

        "library\n  ",

        lib,

        "\nwill be looked up in the directory in which "

        "the target was created rather than in this calling directory."));

  }

  // Handle (additional) case where the command was called with PRIVATE /

  // LINK_PRIVATE and stop its processing. (The "INTERFACE_LINK_LIBRARIES"

  // property of the target on the LHS shall only be populated if it is a

  // STATIC library.)

  if (currentProcessingState == ProcessingKeywordPrivateInterface ||

      currentProcessingState == ProcessingPlainPrivateInterface) {

    if (this->Target->GetType() == cmStateEnums::STATIC_LIBRARY ||

        this->Target->GetType() == cmStateEnums::OBJECT_LIBRARY) {

      // TODO: Detect and no-op `$<COMPILE_ONLY>` genexes here.

      std::string configLib =

        this->Target->GetDebugGeneratorExpressions(lib, llt);

      if (cmGeneratorExpression::IsValidTargetName(lib) ||

          cmGeneratorExpression::Find(lib) != std::string::npos) {

        configLib = "$<LINK_ONLY:" + configLib + ">";

      }

      this->AppendProperty("INTERFACE_LINK_LIBRARIES", configLib);

    }

    return true;

  }

  // Handle general case where the command was called with another keyword than

  // PRIVATE / LINK_PRIVATE or none at all. (The "INTERFACE_LINK_LIBRARIES"

  // property of the target on the LHS shall be populated.)

  this->AppendProperty("INTERFACE_LINK_LIBRARIES",

                       this->Target->GetDebugGeneratorExpressions(lib, llt));

  return true;

}

void TLL::AppendProperty(std::string const& prop, std::string const& value)

{

  this->AffectsProperty(prop);

  this->Target->AppendProperty(prop, value, this->Makefile.GetBacktrace());

}

void TLL::AffectsProperty(std::string const& prop)

{

  if (!this->EncodeRemoteReference) {

    return;

  }

  // Add a wrapper to the expression to tell LookupLinkItem to look up

  // names in the caller's directory.

  if (this->Props.insert(prop).second) {

    this->Target->AppendProperty(prop, this->DirectoryId,

                                 this->Makefile.GetBacktrace());

  }

}

TLL::~TLL()

{

  for (std::string const& prop : this->Props) {

    this->Target->AppendProperty(prop, CMAKE_DIRECTORY_ID_SEP,

                                 this->Makefile.GetBacktrace());

  }

}

} // namespace