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

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

#include "cmDependsC.h"

#include <utility>

#include "cmsys/FStream.hxx"

#include "cmFileTime.h"

#include "cmGlobalUnixMakefileGenerator3.h"

#include "cmList.h"

#include "cmLocalUnixMakefileGenerator3.h"

#include "cmMakefile.h"

#include "cmStringAlgorithms.h"

#include "cmSystemTools.h"

#include "cmValue.h"

#define INCLUDE_REGEX_LINE                                                    \

  "^[ \t]*[#%][ \t]*(include|import)[ \t]*[<\"]([^\">]+)([\">])"

#define INCLUDE_REGEX_LINE_MARKER "#IncludeRegexLine: "

#define INCLUDE_REGEX_SCAN_MARKER "#IncludeRegexScan: "

#define INCLUDE_REGEX_COMPLAIN_MARKER "#IncludeRegexComplain: "

#define INCLUDE_REGEX_TRANSFORM_MARKER "#IncludeRegexTransform: "

cmDependsC::cmDependsC() = default;

cmDependsC::cmDependsC(cmLocalUnixMakefileGenerator3* lg,

                       std::string const& targetDir, std::string const& lang,

                       DependencyMap const* validDeps)

  : cmDepends(lg, targetDir)

  , ValidDeps(validDeps)

{

  cmMakefile* mf = lg->GetMakefile();

  // Configure the include file search path.

  this->SetIncludePathFromLanguage(lang);

  // Configure regular expressions.

  std::string scanRegex = "^.*$";

  std::string complainRegex = "^$";

  {

    std::string scanRegexVar = cmStrCat("CMAKE_", lang, "_INCLUDE_REGEX_SCAN");

    if (cmValue sr = mf->GetDefinition(scanRegexVar)) {

      scanRegex = *sr;

    }

    std::string complainRegexVar =

      cmStrCat("CMAKE_", lang, "_INCLUDE_REGEX_COMPLAIN");

    if (cmValue cr = mf->GetDefinition(complainRegexVar)) {

      complainRegex = *cr;

    }

  }

  this->IncludeRegexLine.compile(INCLUDE_REGEX_LINE);

  this->IncludeRegexScan.compile(scanRegex);

  this->IncludeRegexComplain.compile(complainRegex);

  this->IncludeRegexLineString = INCLUDE_REGEX_LINE_MARKER INCLUDE_REGEX_LINE;

  this->IncludeRegexScanString =

    cmStrCat(INCLUDE_REGEX_SCAN_MARKER, scanRegex);

  this->IncludeRegexComplainString =

    cmStrCat(INCLUDE_REGEX_COMPLAIN_MARKER, complainRegex);

  this->SetupTransforms();

  this->CacheFileName =

    cmStrCat(this->TargetDirectory, '/', lang, ".includecache");

  this->ReadCacheFile();

}

cmDependsC::~cmDependsC()

{

  this->WriteCacheFile();

}

bool cmDependsC::WriteDependencies(std::set<std::string> const& sources,

                                   std::string const& obj,

                                   std::ostream& makeDepends,

                                   std::ostream& internalDepends)

{

  // Make sure this is a scanning instance.

  if (sources.empty() || sources.begin()->empty()) {

    cmSystemTools::Error("Cannot scan dependencies without a source file.");

    return false;

  }

  if (obj.empty()) {

    cmSystemTools::Error("Cannot scan dependencies without an object file.");

    return false;

  }

  std::set<std::string> dependencies;

  bool haveDeps = false;

  // Compute a path to the object file to write to the internal depend file.

  // Any existing content of the internal depend file has already been

  // loaded in ValidDeps with this path as a key.

  std::string obj_i = this->LocalGenerator->MaybeRelativeToTopBinDir(obj);

  if (this->ValidDeps) {

    auto const tmpIt = this->ValidDeps->find(obj_i);

    if (tmpIt != this->ValidDeps->end()) {

      dependencies.insert(tmpIt->second.begin(), tmpIt->second.end());

      haveDeps = true;

    }

  }

  if (!haveDeps) {

    // Walk the dependency graph starting with the source file.

    int srcFiles = static_cast<int>(sources.size());

    this->Encountered.clear();

    for (std::string const& src : sources) {

      UnscannedEntry root;

      root.FileName = src;

      this->Unscanned.push(root);

      this->Encountered.insert(src);

    }

    std::set<std::string> scanned;

    while (!this->Unscanned.empty()) {

      // Get the next file to scan.

      UnscannedEntry current = this->Unscanned.front();

      this->Unscanned.pop();

      // If not a full path, find the file in the include path.

      std::string fullName;

      if ((srcFiles > 0) || cmSystemTools::FileIsFullPath(current.FileName)) {

        if (cmSystemTools::FileExists(current.FileName, true)) {

          fullName = current.FileName;

        }

      } else if (!current.QuotedLocation.empty() &&

                 cmSystemTools::FileExists(current.QuotedLocation, true)) {

        // The include statement producing this entry was a double-quote

        // include and the included file is present in the directory of

        // the source containing the include statement.

        fullName = current.QuotedLocation;

      } else {

        auto headerLocationIt =

          this->HeaderLocationCache.find(current.FileName);

        if (headerLocationIt != this->HeaderLocationCache.end()) {

          fullName = headerLocationIt->second;

        } else {

          for (std::string const& iPath : this->IncludePath) {

            // Construct the name of the file as if it were in the current

            // include directory.  Avoid using a leading "./".

            std::string tmpPath =

              cmSystemTools::CollapseFullPath(current.FileName, iPath);

            // Look for the file in this location.

            if (cmSystemTools::FileExists(tmpPath, true)) {

              fullName = tmpPath;

              this->HeaderLocationCache[current.FileName] = std::move(tmpPath);

              break;

            }

          }

        }

      }

      // Complain if the file cannot be found and matches the complain

      // regex.

      if (fullName.empty() &&

          this->IncludeRegexComplain.find(current.FileName)) {

        cmSystemTools::Error(

          cmStrCat("Cannot find file \"", current.FileName, "\"."));

        return false;

      }

      // Scan the file if it was found and has not been scanned already.

      if (!fullName.empty() && (scanned.find(fullName) == scanned.end())) {

        // Record scanned files.

        scanned.insert(fullName);

        // Check whether this file is already in the cache

        auto fileIt = this->FileCache.find(fullName);

        if (fileIt != this->FileCache.end()) {

          fileIt->second.Used = true;

          dependencies.insert(fullName);

          for (UnscannedEntry const& inc : fileIt->second.UnscannedEntries) {

            if (this->Encountered.find(inc.FileName) ==

                this->Encountered.end()) {

              this->Encountered.insert(inc.FileName);

              this->Unscanned.push(inc);

            }

          }

        } else {

          // Try to scan the file.  Just leave it out if we cannot find

          // it.

          cmsys::ifstream fin(fullName.c_str());

          if (fin) {

            cmsys::FStream::BOM bom = cmsys::FStream::ReadBOM(fin);

            if (bom == cmsys::FStream::BOM_None ||

                bom == cmsys::FStream::BOM_UTF8) {

              // Add this file as a dependency.

              dependencies.insert(fullName);

              // Scan this file for new dependencies.  Pass the directory

              // containing the file to handle double-quote includes.

              std::string dir = cmSystemTools::GetFilenamePath(fullName);

              this->Scan(fin, dir, fullName);

            } else {

              // Skip file with encoding we do not implement.

            }

          }

        }

      }

      srcFiles--;

    }

  }

  // Write the dependencies to the output stream.  Makefile rules

  // written by the original local generator for this directory

  // convert the dependencies to paths relative to the home output

  // directory.  We must do the same here.

  std::string obj_m = this->LocalGenerator->ConvertToMakefilePath(obj_i);

  internalDepends << obj_i << '\n';

  if (!dependencies.empty()) {

    auto const& lineContinue = static_cast<cmGlobalUnixMakefileGenerator3*>(

                                 this->LocalGenerator->GetGlobalGenerator())

                                 ->LineContinueDirective;

    bool supportLongLineDepend = static_cast<cmGlobalUnixMakefileGenerator3*>(

                                   this->LocalGenerator->GetGlobalGenerator())

                                   ->SupportsLongLineDependencies();

    if (supportLongLineDepend) {

      makeDepends << obj_m << ':';

    }

    for (std::string const& dep : dependencies) {

      std::string dependee = this->LocalGenerator->ConvertToMakefilePath(

        this->LocalGenerator->MaybeRelativeToTopBinDir(dep));

      if (supportLongLineDepend) {

        makeDepends << ' ' << lineContinue << ' ' << dependee;

      } else {

        makeDepends << obj_m << ": " << dependee << '\n';

      }

      internalDepends << ' ' << dep << '\n';

    }

    makeDepends << '\n';

  }

  return true;

}

void cmDependsC::ReadCacheFile()

{

  if (this->CacheFileName.empty()) {

    return;

  }

  cmsys::ifstream fin(this->CacheFileName.c_str());

  if (!fin) {

    return;

  }

  std::string line;

  cmIncludeLines* cacheEntry = nullptr;

  bool haveFileName = false;

  cmFileTime cacheFileTime;

  bool const cacheFileTimeGood = cacheFileTime.Load(this->CacheFileName);

  while (cmSystemTools::GetLineFromStream(fin, line)) {

    if (line.empty()) {

      cacheEntry = nullptr;

      haveFileName = false;

      continue;

    }

    // the first line after an empty line is the name of the parsed file

    if (!haveFileName) {

      haveFileName = true;

      cmFileTime fileTime;

      bool const res = cacheFileTimeGood && fileTime.Load(line);

      bool const newer = res && cacheFileTime.Newer(fileTime);

      if (res && newer) // cache is newer than the parsed file

      {

        cacheEntry = &this->FileCache[line];

      }

      // file doesn't exist, check that the regular expressions

      // haven't changed

      else if (!res) {

        if (cmHasLiteralPrefix(line, INCLUDE_REGEX_LINE_MARKER)) {

          if (line != this->IncludeRegexLineString) {

            return;

          }

        } else if (cmHasLiteralPrefix(line, INCLUDE_REGEX_SCAN_MARKER)) {

          if (line != this->IncludeRegexScanString) {

            return;

          }

        } else if (cmHasLiteralPrefix(line, INCLUDE_REGEX_COMPLAIN_MARKER)) {

          if (line != this->IncludeRegexComplainString) {

            return;

          }

        } else if (cmHasLiteralPrefix(line, INCLUDE_REGEX_TRANSFORM_MARKER)) {

          if (line != this->IncludeRegexTransformString) {

            return;

          }

        }

      }

    } else if (cacheEntry) {

      UnscannedEntry entry;

      entry.FileName = line;

      if (cmSystemTools::GetLineFromStream(fin, line)) {

        if (line != "-") {

          entry.QuotedLocation = line;

        }

        cacheEntry->UnscannedEntries.push_back(std::move(entry));

      }

    }

  }

}

void cmDependsC::WriteCacheFile() const

{

  if (this->CacheFileName.empty()) {

    return;

  }

  cmsys::ofstream cacheOut(this->CacheFileName.c_str());

  if (!cacheOut) {

    return;

  }

  cacheOut << this->IncludeRegexLineString << "\n\n";

  cacheOut << this->IncludeRegexScanString << "\n\n";

  cacheOut << this->IncludeRegexComplainString << "\n\n";

  cacheOut << this->IncludeRegexTransformString << "\n\n";

  for (auto const& fileIt : this->FileCache) {

    if (fileIt.second.Used) {

      cacheOut << fileIt.first << '\n';

      for (UnscannedEntry const& inc : fileIt.second.UnscannedEntries) {

        cacheOut << inc.FileName << '\n';

        if (inc.QuotedLocation.empty()) {

          cacheOut << '-' << '\n';

        } else {

          cacheOut << inc.QuotedLocation << '\n';

        }

      }

      cacheOut << '\n';

    }

  }

}

void cmDependsC::Scan(std::istream& is, std::string const& directory,

                      std::string const& fullName)

{

  cmIncludeLines& newCacheEntry = this->FileCache[fullName];

  newCacheEntry.Used = true;

  // Read one line at a time.

  std::string line;

  while (cmSystemTools::GetLineFromStream(is, line)) {

    // Transform the line content first.

    if (!this->TransformRules.empty()) {

      this->TransformLine(line);

    }

    // Match include directives.

    if (this->IncludeRegexLine.find(line)) {

      // Get the file being included.

      UnscannedEntry entry;

      entry.FileName = this->IncludeRegexLine.match(2);

      cmSystemTools::ConvertToUnixSlashes(entry.FileName);

      if (this->IncludeRegexLine.match(3) == "\"" &&

          !cmSystemTools::FileIsFullPath(entry.FileName)) {

        // This was a double-quoted include with a relative path.  We

        // must check for the file in the directory containing the

        // file we are scanning.

        entry.QuotedLocation =

          cmSystemTools::CollapseFullPath(entry.FileName, directory);

      }

      // Queue the file if it has not yet been encountered and it

      // matches the regular expression for recursive scanning.  Note

      // that this check does not account for the possibility of two

      // headers with the same name in different directories when one

      // is included by double-quotes and the other by angle brackets.

      // It also does not work properly if two header files with the same

      // name exist in different directories, and both are included from a

      // file their own directory by simply using "filename.h" (#12619)

      // This kind of problem will be fixed when a more

      // preprocessor-like implementation of this scanner is created.

      if (this->IncludeRegexScan.find(entry.FileName)) {

        newCacheEntry.UnscannedEntries.push_back(entry);

        if (this->Encountered.find(entry.FileName) ==

            this->Encountered.end()) {

          this->Encountered.insert(entry.FileName);

          this->Unscanned.push(entry);

        }

      }

    }

  }

}

void cmDependsC::SetupTransforms()

{

  // Get the transformation rules.

  cmMakefile* mf = this->LocalGenerator->GetMakefile();

  cmList transformRules{ mf->GetDefinition("CMAKE_INCLUDE_TRANSFORMS"),

                         cmList::EmptyElements::Yes };

  for (auto const& tr : transformRules) {

    this->ParseTransform(tr);

  }

  this->IncludeRegexTransformString = INCLUDE_REGEX_TRANSFORM_MARKER;

  if (!this->TransformRules.empty()) {

    // Construct the regular expression to match lines to be

    // transformed.

    std::string xform = "^([ \t]*[#%][ \t]*(include|import)[ \t]*)(";

    char const* sep = "";

    for (auto const& tr : this->TransformRules) {

      xform += sep;

      xform += tr.first;

      sep = "|";

    }

    xform += ")[ \t]*\\(([^),]*)\\)";

    this->IncludeRegexTransform.compile(xform);

    // Build a string that encodes all transformation rules and will

    // change when rules are changed.

    this->IncludeRegexTransformString += xform;

    for (auto const& tr : this->TransformRules) {

      this->IncludeRegexTransformString += " ";

      this->IncludeRegexTransformString += tr.first;

      this->IncludeRegexTransformString += "(%)=";

      this->IncludeRegexTransformString += tr.second;

    }

  }

}

void cmDependsC::ParseTransform(std::string const& xform)

{

  // A transform rule is of the form SOME_MACRO(%)=value-with-%

  // We can simply separate with "(%)=".

  std::string::size_type pos = xform.find("(%)=");

  if (pos == std::string::npos || pos == 0) {

    return;

  }

  std::string name = xform.substr(0, pos);

  std::string value = xform.substr(pos + 4);

  this->TransformRules[name] = value;

}

void cmDependsC::TransformLine(std::string& line)

{

  // Check for a transform rule match.  Return if none.

  if (!this->IncludeRegexTransform.find(line)) {

    return;

  }

  auto tri = this->TransformRules.find(this->IncludeRegexTransform.match(3));

  if (tri == this->TransformRules.end()) {

    return;

  }

  // Construct the transformed line.

  std::string newline = this->IncludeRegexTransform.match(1);

  std::string arg = this->IncludeRegexTransform.match(4);

  for (char c : tri->second) {

    if (c == '%') {

      newline += arg;

    } else {

      newline += c;

    }

  }

  // Return the transformed line.

  line = newline;

}