Report missing file errors with their own exception type

Reinstantiate the file_not_found_error exception type removed during the
separation of utils::lua from Kyua.  We need this to provide better error
messages to the user when he asks the library to load a non-existent
file.

This change was r3 in Subversion.

exceptions.cpp

@@ -94,3 +94,30 @@ lutok::api_error::api_function(void) const
 {
     return _api_function;
 }
+
+
+/// Constructs a new error.
+///
+/// \param filename_ The file that count not be found.
+lutok::file_not_found_error::file_not_found_error(
+    const std::string& filename_) :
+    error("File '" + filename_ + "' not found"),
+    _filename(filename_)
+{
+}
+
+
+/// Destructor for the error.
+lutok::file_not_found_error::~file_not_found_error(void) throw()
+{
+}
+
+
+/// Gets the name of the file that could not be found.
+///
+/// \return The name of the file.
+const std::string&
+lutok::file_not_found_error::filename(void) const
+{
+    return _filename;
+}

exceptions.hpp

@@ -65,6 +65,18 @@ class api_error : public error {
 };
 
 
+/// File not found error.
+class file_not_found_error : public error {
+    std::string _filename;
+
+public:
+    explicit file_not_found_error(const std::string&);
+    virtual ~file_not_found_error(void) throw();
+
+    const std::string& filename(void) const;
+};
+
+
 }  // namespace lutok
 
 

exceptions_test.cpp

@@ -66,10 +66,21 @@ ATF_TEST_CASE_BODY(api_error__from_stack)
 }
 
 
+ATF_TEST_CASE_WITHOUT_HEAD(file_not_found_error);
+ATF_TEST_CASE_BODY(file_not_found_error)
+{
+    const lutok::file_not_found_error e("missing-file");
+    ATF_REQUIRE(std::strcmp("File 'missing-file' not found", e.what()) == 0);
+    ATF_REQUIRE_EQ("missing-file", e.filename());
+}
+
+
 ATF_INIT_TEST_CASES(tcs)
 {
     ATF_ADD_TEST_CASE(tcs, error);
 
     ATF_ADD_TEST_CASE(tcs, api_error__explicit);
     ATF_ADD_TEST_CASE(tcs, api_error__from_stack);
+
+    ATF_ADD_TEST_CASE(tcs, file_not_found_error);
 }

operations_test.cpp

@@ -175,7 +175,7 @@ ATF_TEST_CASE_BODY(do_file__not_found)
 {
     lutok::state state;
     stack_balance_checker checker(state);
-    ATF_REQUIRE_THROW_RE(lutok::error, "Failed to load Lua file 'missing.lua'",
+    ATF_REQUIRE_THROW_RE(lutok::file_not_found_error, "missing.lua",
                          lutok::do_file(state, "missing.lua"));
 }
 

wrap.cpp

@@ -26,6 +26,10 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+extern "C" {
+#include <unistd.h>
+}
+
 #include <cassert>
 #include <cstring>
 
@@ -360,11 +364,14 @@ lutok::state::is_userdata(const int index)
 /// \param file The second parameter to luaL_loadfile.
 ///
 /// \throw api_error If luaL_loadfile returns an error.
+/// \throw file_not_found_error If the file cannot be accessed.
 ///
 /// \warning Terminates execution if there is not enough memory.
 void
 lutok::state::load_file(const std::string& file)
 {
+    if (!::access(file.c_str(), R_OK) == 0)
+        throw lutok::file_not_found_error(file);
     if (luaL_loadfile(_pimpl->lua_state, file.c_str()) != 0)
         throw lutok::api_error::from_stack(_pimpl->lua_state, "luaL_loadfile");
 }

wrap_test.cpp

@@ -615,11 +615,12 @@ ATF_TEST_CASE_BODY(state__load_file__api_error)
 }
 
 
-ATF_TEST_CASE_WITHOUT_HEAD(state__load_file__missing);
-ATF_TEST_CASE_BODY(state__load_file__missing)
+ATF_TEST_CASE_WITHOUT_HEAD(state__load_file__file_not_found_error);
+ATF_TEST_CASE_BODY(state__load_file__file_not_found_error)
 {
     lutok::state state;
-    REQUIRE_API_ERROR("luaL_loadfile", state.load_file("missing.lua"));
+    ATF_REQUIRE_THROW_RE(lutok::file_not_found_error, "missing.lua",
+                         state.load_file("missing.lua"));
 }
 
 
@@ -1278,7 +1279,7 @@ ATF_INIT_TEST_CASES(tcs)
     ATF_ADD_TEST_CASE(tcs, state__is_userdata__explicit);
     ATF_ADD_TEST_CASE(tcs, state__load_file__ok);
     ATF_ADD_TEST_CASE(tcs, state__load_file__api_error);
-    ATF_ADD_TEST_CASE(tcs, state__load_file__missing);
+    ATF_ADD_TEST_CASE(tcs, state__load_file__file_not_found_error);
     ATF_ADD_TEST_CASE(tcs, state__load_string__ok);
     ATF_ADD_TEST_CASE(tcs, state__load_string__fail);
     ATF_ADD_TEST_CASE(tcs, state__new_table);