Modernize datadir

src/api/baseapi.cpp

@@ -146,6 +146,10 @@ static void ExtractFontName(const char* filename, std::string* fontname) {
  */
 static void addAvailableLanguages(const std::string &datadir,
                                   std::vector<std::string> *langs) {
+  if (!std::filesystem::exists(datadir) ||
+      !std::filesystem::is_directory(datadir)) {
+    return;
+  }
   for (const auto& entry :
        std::filesystem::recursive_directory_iterator(datadir,
          std::filesystem::directory_options::follow_directory_symlink |
@@ -347,7 +351,7 @@ int TessBaseAPI::Init(const char *data, int data_size, const char *language, Ocr
   // Update datapath and language requested for the last valid initialization.
   datapath_ = std::move(datapath);
   if (datapath_.empty() && !tesseract_->datadir.empty()) {
-    datapath_ = tesseract_->datadir;
+    datapath_ = tesseract_->datadir.string();
   }
 
   language_ = language;
@@ -396,7 +400,7 @@ void TessBaseAPI::GetLoadedLanguagesAsVector(std::vector<std::string> *langs) co
 void TessBaseAPI::GetAvailableLanguagesAsVector(std::vector<std::string> *langs) const {
   langs->clear();
   if (tesseract_ != nullptr) {
-    addAvailableLanguages(tesseract_->datadir, langs);
+    addAvailableLanguages(tesseract_->datadir.string().c_str(), langs);
     std::sort(langs->begin(), langs->end());
   }
 }
@@ -858,7 +862,7 @@ const char *TessBaseAPI::GetInputName() {
 }
 
 const char *TessBaseAPI::GetDatapath() {
-  return tesseract_->datadir.c_str();
+  return datapath_.c_str();
 }
 
 int TessBaseAPI::GetSourceYResolution() {

src/ccmain/paramsd.cpp

@@ -298,7 +298,7 @@ ParamsEditor::ParamsEditor(tesseract::Tesseract *tess, ScrollView *sv) {
   SVMenuNode *svMenuRoot = BuildListOfAllLeaves(tess);
 
   std::string paramfile;
-  paramfile = tess->datadir;
+  paramfile = tess->datadir.string();
   paramfile += VARDIR;   // parameters dir
   paramfile += "edited"; // actual name
 

src/ccmain/tessedit.cpp

@@ -43,24 +43,25 @@ namespace tesseract {
 // Read a "config" file containing a set of variable, value pairs.
 // Searches the standard places: tessdata/configs, tessdata/tessconfigs
 // and also accepts a relative or absolute path name.
-void Tesseract::read_config_file(const char *filename, SetParamConstraint constraint) {
-  std::string path = datadir;
-  path += "configs/";
-  path += filename;
-  FILE *fp;
-  if ((fp = fopen(path.c_str(), "rb")) != nullptr) {
-    fclose(fp);
-  } else {
-    path = datadir;
-    path += "tessconfigs/";
-    path += filename;
-    if ((fp = fopen(path.c_str(), "rb")) != nullptr) {
-      fclose(fp);
-    } else {
-      path = filename;
-    }
-  }
-  ParamUtils::ReadParamsFile(path.c_str(), constraint, this->params());
+void Tesseract::read_config_file(const char *filename,
+                                 SetParamConstraint constraint) {
+  // Construct potential config file paths
+  std::vector<std::filesystem::path> config_paths = {
+      datadir / "configs" / filename,
+      datadir / "tessconfigs" / filename,
+      std::filesystem::path(filename)};
+
+  // Use the first existing file or fallback to the last (filename)
+  auto config_file = std::find_if(config_paths.begin(), config_paths.end(),
+                                  [](const std::filesystem::path &path) {
+                                    std::error_code ec;
+                                    return std::filesystem::exists(path, ec);
+                                  });
+  const std::filesystem::path &selected_path =
+      (config_file != config_paths.end()) ? *config_file : config_paths.back();
+
+  ParamUtils::ReadParamsFile(selected_path.string().c_str(), constraint,
+                             this->params());
 }
 
 // Returns false if a unicharset file for the specified language was not found
@@ -81,14 +82,11 @@ bool Tesseract::init_tesseract_lang_data(const std::string &arg0,
                                          bool set_only_non_debug_params, TessdataManager *mgr) {
   // Set the language data path prefix
   lang = !language.empty() ? language : "eng";
-  language_data_path_prefix = datadir;
-  language_data_path_prefix += lang;
-  language_data_path_prefix += ".";
+  std::filesystem::path tessdata_path = datadir / (lang + "." + kTrainedDataSuffix);
 
   // Initialize TessdataManager.
-  std::string tessdata_path = language_data_path_prefix + kTrainedDataSuffix;
-  if (!mgr->is_loaded() && !mgr->Init(tessdata_path.c_str())) {
-    tprintf("Error opening data file %s\n", tessdata_path.c_str());
+  if (!mgr->is_loaded() && !mgr->Init(tessdata_path.string().c_str())) {
+    tprintf("Error opening data file %s\n", tessdata_path.string().c_str());
     tprintf(
         "Please make sure the TESSDATA_PREFIX environment variable is set"
         " to your \"tessdata\" directory.\n");
@@ -187,7 +185,7 @@ bool Tesseract::init_tesseract_lang_data(const std::string &arg0,
     tprintf(
         "Error: Tesseract (legacy) engine requested, but components are "
         "not present in %s!!\n",
-        tessdata_path.c_str());
+        tessdata_path.string().c_str());
     return false;
   }
 #endif // ndef DISABLED_LEGACY_ENGINE

src/ccutil/ccutil.cpp

@@ -14,8 +14,6 @@
 #include "tprintf.h"  // for tprintf
 
 #include <cstdlib>
-#include <cstring>    // for std::strrchrA
-#include <filesystem> // for std::filesystem
 
 namespace tesseract {
 
@@ -33,68 +31,74 @@ CCUtil::CCUtil()
 CCUtil::~CCUtil() = default;
 
 /**
- * @brief CCUtil::main_setup - set location of tessdata and name of image
+ * @brief Finds the path to the tessdata directory.
  *
- * @param argv0 - paths to the directory with language files and config files.
- * An actual value of argv0 is used if not nullptr, otherwise TESSDATA_PREFIX is
- * used if not nullptr, next try to use compiled in -DTESSDATA_PREFIX. If
- * previous is not successful - use current directory.
- * @param basename - name of image
+ * This function determines the location of the tessdata directory based on the
+ * following order of precedence:
+ * 1. If `argv0` is provided, use it.
+ * 2. If `TESSDATA_PREFIX` environment variable is set and the path exists, use
+ *    it.
+ * 3. On Windows, check for a "tessdata" directory in the executable's directory
+ *    and use it.
+ * 4. If `TESSDATA_PREFIX` is defined at compile time, use it.
+ * 5. Otherwise, use the current working directory.
+ *
+ * @param argv0 argument to be considered as the data directory path.
+ * @return The path to the tessdata directory or current directory.
  */
-void CCUtil::main_setup(const std::string &argv0, const std::string &basename) {
-  imagebasename = basename; /**< name of image */
-
-  const char *tessdata_prefix = getenv("TESSDATA_PREFIX");
-
-  // Ignore TESSDATA_PREFIX if there is no matching filesystem entry.
-  if (tessdata_prefix != nullptr && !std::filesystem::exists(tessdata_prefix)) {
-    tprintf("Warning: TESSDATA_PREFIX %s does not exist, ignore it\n", tessdata_prefix);
-    tessdata_prefix = nullptr;
-  }
-
+std::filesystem::path find_data_path(const std::string &argv0) {
+  // If argv0 is set, always use it even if it is not a valid directory
   if (!argv0.empty()) {
-    /* Use tessdata prefix from the command line. */
-    datadir = argv0;
-  } else if (tessdata_prefix) {
-    /* Use tessdata prefix from the environment. */
-    datadir = tessdata_prefix;
-#if defined(_WIN32)
-  } else if (datadir.empty() || !std::filesystem::exists(datadir)) {
-    /* Look for tessdata in directory of executable. */
-    char path[_MAX_PATH];
-    DWORD length = GetModuleFileName(nullptr, path, sizeof(path));
-    if (length > 0 && length < sizeof(path)) {
-      char *separator = std::strrchr(path, '\\');
-      if (separator != nullptr) {
-        *separator = '\0';
-        std::string subdir = path;
-        subdir += "/tessdata";
-        if (std::filesystem::exists(subdir)) {
-          datadir = subdir;
-        }
-      }
+    std::filesystem::path path(argv0);
+    if (!std::filesystem::exists(path) ||
+        !std::filesystem::is_directory(path)) {
+      tprintf("Warning (tessdata): '%s' is not a valid directory.\n",
+              argv0.c_str());
     }
-#endif /* _WIN32 */
+    return path;
   }
 
-  // datadir may still be empty:
-  if (datadir.empty()) {
-#if defined(TESSDATA_PREFIX)
-    // Use tessdata prefix which was compiled in.
-    datadir = TESSDATA_PREFIX "/tessdata/";
-    // Note that some software (for example conda) patches TESSDATA_PREFIX
-    // in the binary, so it might be shorter. Recalculate its length.
-    datadir.resize(std::strlen(datadir.c_str()));
-#else
-    datadir = "./";
-#endif /* TESSDATA_PREFIX */
+  // Check environment variable if argv0 is not specified
+  if (const char *tessdata_prefix = std::getenv("TESSDATA_PREFIX")) {
+    std::filesystem::path path(tessdata_prefix);
+    if (std::filesystem::exists(path)) {
+      return path;
+    } else {
+      tprintf("Warning: TESSDATA_PREFIX %s does not exist, ignoring.\n",
+              tessdata_prefix);
+    }
   }
 
-  // check for missing directory separator
-  const char lastchar = datadir.back();
-  if (lastchar != '/' && lastchar != '\\') {
-    datadir += '/';
+#ifdef _WIN32
+  // Windows-specific: check for 'tessdata' not existing in the executable
+  // directory
+  wchar_t path[MAX_PATH];
+  if (DWORD length = GetModuleFileNameW(nullptr, path, MAX_PATH);
+      length > 0 && length < MAX_PATH) {
+    std::filesystem::path exe_path(path);
+    auto tessdata_subdir = exe_path.parent_path() / "tessdata";
+    if (std::filesystem::exists(tessdata_subdir)) {
+      return tessdata_subdir;
+    }
   }
+#endif
+
+  // Fallback to compile-time or current directory
+#ifdef TESSDATA_PREFIX
+  return std::filesystem::path(TESSDATA_PREFIX) / "tessdata";
+#else
+  return std::filesystem::current_path();
+#endif
 }
 
+
+/**
+ * @brief CCUtil::main_setup - set location of tessdata and name of image
+ *
+ * @param argv0 - paths to the directory with language files and config files.
+ */
+void CCUtil::main_setup(const std::string &argv0, const std::string &basename) {
+  imagebasename = basename; /**< name of image */
+  datadir = find_data_path(argv0);
+}
 } // namespace tesseract

src/ccutil/ccutil.h

@@ -19,6 +19,8 @@
 #ifndef TESSERACT_CCUTIL_CCUTIL_H_
 #define TESSERACT_CCUTIL_CCUTIL_H_
 
+#include <filesystem> // for std::filesystem
+
 #ifndef _WIN32
 #  include <pthread.h>
 #  include <semaphore.h>
@@ -53,9 +55,8 @@ class TESS_API CCUtil {
   ParamsVectors *params() {
     return &params_;
   }
-
-  std::string datadir;       // dir for data files
-  std::string imagebasename; // name of image
+  std::filesystem::path datadir; // dir for data files
+  std::string imagebasename;     // name of image
   std::string lang;
   std::string language_data_path_prefix;
   UNICHARSET unicharset;