6 files changed, 167 insertions, 0 deletions
diff --git a/host/lib/include/uhdlib/utils/paths.hpp b/host/lib/include/uhdlib/utils/paths.hpp
new file mode 100644
index 000000000..d74973301
--- /dev/null
+++ b/host/lib/include/uhdlib/utils/paths.hpp
@@ -0,0 +1,24 @@
+//
+// Copyright 2018 Ettus Research, a National Instruments Company
+//
+// SPDX-License-Identifier: GPL-3.0+
+//
+
+#ifndef INCLUDED_UHDLIB_UTILS_PATHS_HPP
+#define INCLUDED_UHDLIB_UTILS_PATHS_HPP
+
+#include <string>
+
+namespace uhd {
+
+    /*! Expand environment variables in paths, like Python's
+     *  os.path.expandvars().
+     *
+     * If expansion fails, will simply return the original path.
+     */
+    std::string path_expandvars(const std::string& path);
+
+} /* namespace uhd */
+
+#endif /* INCLUDED_UHDLIB_UTILS_PATHS_HPP */
+
diff --git a/host/lib/utils/CMakeLists.txt b/host/lib/utils/CMakeLists.txt
index 7af094e83..62d1ba090 100644
--- a/host/lib/utils/CMakeLists.txt
+++ b/host/lib/utils/CMakeLists.txt
@@ -168,6 +168,7 @@ LIBUHD_APPEND_SOURCES(
     ${CMAKE_CURRENT_SOURCE_DIR}/load_modules.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/log.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/paths.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/pathslib.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/platform.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/static.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/tasks.cpp
diff --git a/host/lib/utils/paths.cpp b/host/lib/utils/paths.cpp
index d609e254f..8a7ba001f 100644
--- a/host/lib/utils/paths.cpp
+++ b/host/lib/utils/paths.cpp
@@ -8,6 +8,7 @@
 #include <uhd/config.hpp>
 #include <uhd/exception.hpp>
 #include <uhd/utils/paths.hpp>
+#include <uhdlib/utils/paths.hpp>
 
 #include <boost/algorithm/string.hpp>
 #include <boost/bind.hpp>
@@ -96,6 +97,7 @@ static std::vector<std::string> get_env_paths(const std::string &var_name){
 }
 
 #ifndef UHD_PLATFORM_WIN32
+// NOTE: This could be replaced by path_expandvars()
 /*! Expand a tilde character to the $HOME path.
  *
  * The path passed to this function must start with the tilde character in order
diff --git a/host/lib/utils/pathslib.cpp b/host/lib/utils/pathslib.cpp
new file mode 100644
index 000000000..cbb0d0917
--- /dev/null
+++ b/host/lib/utils/pathslib.cpp
@@ -0,0 +1,45 @@
+//
+// Copyright 2018 Ettus Research, a National Instruments Company
+//
+// SPDX-License-Identifier: GPL-3.0+
+//
+
+#include <uhd/config.hpp>
+#include <uhdlib/utils/paths.hpp>
+
+#ifdef BOOST_MSVC
+#  include <windows.h>
+#else
+#  include <wordexp.h>
+#endif
+
+std::string uhd::path_expandvars(const std::string& path)
+{
+    if (path.empty()) {
+        return path;
+    }
+#ifdef BOOST_MSVC
+    constexpr size_t max_pathlen = 4096;
+    char result[max_pathlen];
+    const size_t result_len = ExpandEnvironmentStrings(
+        path.c_str(),
+        &result[0],
+        max_pathlen
+    );
+    if (result == 0) {
+        return path;
+    }
+    return std::string(result, result+result_len);
+#else
+    wordexp_t p;
+    std::string return_value;
+    if (wordexp(path.c_str(), &p, 0) == 0 && p.we_wordc > 0) {
+        return_value = std::string(p.we_wordv[0]);
+    } else {
+        return_value = path;
+    }
+    wordfree(&p);
+    return return_value;
+#endif
+}
+
diff --git a/host/tests/CMakeLists.txt b/host/tests/CMakeLists.txt
index 437a697d0..7d53b50c4 100644
--- a/host/tests/CMakeLists.txt
+++ b/host/tests/CMakeLists.txt
@@ -125,6 +125,29 @@ UHD_INSTALL(TARGETS
     COMPONENT tests
 )
 
+ADD_EXECUTABLE(paths_test
+    paths_test.cpp
+    ${CMAKE_SOURCE_DIR}/lib/utils/pathslib.cpp
+)
+# Careful: This is to satisfy the out-of-library build of paths.cpp. This is
+# duplicate code from lib/utils/CMakeLists.txt, and it's been simplified.
+SET(UHD_LIB_DIR "lib")
+FILE(TO_NATIVE_PATH "${CMAKE_INSTALL_PREFIX}" UHD_PKG_PATH)
+STRING(REPLACE "\\" "\\\\" UHD_PKG_PATH "${UHD_PKG_PATH}")
+SET_SOURCE_FILES_PROPERTIES(
+    ${CMAKE_SOURCE_DIR}/lib/utils/paths.cpp
+    PROPERTIES COMPILE_DEFINITIONS
+    "UHD_PKG_PATH=\"${UHD_PKG_PATH}\";UHD_LIB_DIR=\"${UHD_LIB_DIR}\""
+)
+TARGET_LINK_LIBRARIES(paths_test uhd ${Boost_LIBRARIES})
+UHD_ADD_TEST(paths_test paths_test)
+UHD_INSTALL(TARGETS
+    paths_test
+    RUNTIME
+    DESTINATION ${PKG_LIB_DIR}/tests
+    COMPONENT tests
+)
+
 ########################################################################
 # demo of a loadable module
 ########################################################################
diff --git a/host/tests/paths_test.cpp b/host/tests/paths_test.cpp
new file mode 100644
index 000000000..0ccebd333
--- /dev/null
+++ b/host/tests/paths_test.cpp
@@ -0,0 +1,72 @@
+//
+// Copyright 2018 Ettus Research, a National Instruments Company
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+
+#include <uhd/config.hpp>
+#include <uhd/exception.hpp>
+#include <uhd/utils/paths.hpp>
+#include <uhdlib/utils/paths.hpp>
+#include <boost/test/unit_test.hpp>
+#include <boost/filesystem/operations.hpp>
+#include <vector>
+#include <iostream>
+
+BOOST_AUTO_TEST_CASE(test_paths_expandvars) {
+#ifdef UHD_PLATFORM_WIN32
+    const std::string path_to_expand("\%programdata%/uhd/uhd.conf");
+#else
+    const std::string path_to_expand("$HOME/.uhd/uhd.conf");
+#endif
+    const std::string expanded_path = uhd::path_expandvars(path_to_expand);
+
+    std::cout << "Expanded path: " << path_to_expand << " -> "
+              << expanded_path << std::endl;
+    BOOST_CHECK(path_to_expand != expanded_path);
+
+#ifdef UHD_PLATFORM_WIN32
+    const std::string var_identifier = "%";
+#else
+    const std::string var_identifier = "$";
+#endif
+
+    BOOST_CHECK(expanded_path.find(var_identifier) == std::string::npos);
+}
+
+
+BOOST_AUTO_TEST_CASE(test_get_paths) {
+    using namespace uhd;
+
+    const std::string tmp_path = get_tmp_path();
+    const std::string app_path = get_app_path();
+    const std::string pkg_path = get_pkg_path();
+    const auto module_paths = get_module_paths();
+
+    std::cout << "tmp_path: " << tmp_path << std::endl;
+    std::cout << "app_path: " << app_path << std::endl;
+    std::cout << "pkg_path: " << pkg_path << std::endl;
+    for (const auto& module_path : module_paths) {
+        std::cout << "module path: " << module_path << std::endl;
+    }
+
+    const std::string images_dir_search_path = "";
+    const std::string images_dir = get_images_dir(images_dir_search_path);
+    BOOST_REQUIRE_THROW(
+        find_image_path("this_device_does_not_exist.bit", ""),
+        uhd::io_error
+    );
+
+    const std::string utility_path = find_utility(
+            "uhd_images_downloader"
+    );
+    std::cout << "utility_path: " << utility_path << std::endl;
+
+    const std::string utility_error = print_utility_error(
+            "uhd_images_downloader",
+            "--help"
+    );
+    std::cout << "utility_error: " << tmp_path << std::endl;
+
+}
+