Vars::unset: API method for removing variable

include/libdnf5/conf/vars.hpp

@@ -79,6 +79,14 @@ struct Vars {
     /// @throw ReadOnlyVariableError if the variable is read-only
     void set(const std::string & name, const std::string & value, Priority prio = Priority::RUNTIME);
 
+    /// @brief Unset particular variable
+    ///
+    /// @param name Name of the variable
+    /// @param prio Source/Priority of the request
+    /// @throw ReadOnlyVariableError if the variable is read-only
+    /// @return false if the variable exists after the function returns (insufficient request priority)
+    bool unset(const std::string & name, Priority prio = Priority::RUNTIME);
+
     /// @brief Checks whether a variable is read-only
     ///
     /// @param name Name of the variable

libdnf5/conf/vars.cpp

@@ -386,6 +386,22 @@ void Vars::set(const std::string & name, const std::string & value, Priority pri
     set_unsafe(name, value, prio);
 }
 
+bool Vars::unset(const std::string & name, Priority prio) {
+    auto it = variables.find(name);
+    if (it == variables.end()) {
+        return true;
+    }
+    if (is_read_only(name)) {
+        throw ReadOnlyVariableError(M_("Variable \"{}\" is read-only"), name);
+    }
+    // Do nothing if the var is already set with a higher priority
+    if (prio < it->second.priority) {
+        return false;
+    }
+    variables.erase(it);
+    return true;
+}
+
 void Vars::set_lazy(
     const std::string & name,
     const std::function<const std::unique_ptr<const std::string>()> & get_value,

test/libdnf5/conf/test_vars.cpp

@@ -23,28 +23,31 @@ along with libdnf.  If not, see <https://www.gnu.org/licenses/>.
 
 CPPUNIT_TEST_SUITE_REGISTRATION(VarsTest);
 
+using namespace std::literals::string_literals;
+
 // TODO possibly test the automatically detected vars (they depend on the host)
 
 void VarsTest::setUp() {
     TestCaseFixture::setUp();
     base = get_preconfigured_base();
 }
 
+
 void VarsTest::test_vars() {
     base->get_config().get_varsdir_option().set(
         std::vector<std::string>{PROJECT_SOURCE_DIR "/test/libdnf5/conf/data/vars"});
     // Load all variables.
     base->setup();
 
-    CPPUNIT_ASSERT_EQUAL(std::string("foovalue123-bar"), base->get_vars()->substitute("foo$var1-bar"));
+    CPPUNIT_ASSERT_EQUAL("foovalue123-bar"s, base->get_vars()->substitute("foo$var1-bar"));
+    CPPUNIT_ASSERT_EQUAL("$$$value123456-$nn-${nnn}"s, base->get_vars()->substitute("$$$${var1}$var2-$nn-${nnn}"));
     CPPUNIT_ASSERT_EQUAL(
-        std::string("$$$value123456-$nn-${nnn}"), base->get_vars()->substitute("$$$${var1}$var2-$nn-${nnn}"));
-    CPPUNIT_ASSERT_EQUAL(
-        std::string("alternate-default-${nn:+n${nn:-${nnn:}"),
+        "alternate-default-${nn:+n${nn:-${nnn:}"s,
         base->get_vars()->substitute("${var1:+alternate}-${unset:-default}-${nn:+n${nn:-${nnn:}"));
-    CPPUNIT_ASSERT_EQUAL(std::string("456"), base->get_vars()->substitute("${unset:-${var1:+${var2:+$var2}}}"));
+    CPPUNIT_ASSERT_EQUAL("456"s, base->get_vars()->substitute("${unset:-${var1:+${var2:+$var2}}}"));
 }
 
+
 void VarsTest::test_vars_multiple_dirs() {
     base->get_config().get_varsdir_option().set(std::vector<std::string>{
         PROJECT_SOURCE_DIR "/test/libdnf5/conf/data/vars",
@@ -53,9 +56,10 @@ void VarsTest::test_vars_multiple_dirs() {
     // Load all variables.
     base->setup();
 
-    CPPUNIT_ASSERT_EQUAL(std::string("av333bthe answer is here"), base->get_vars()->substitute("a${var1}b${var42}"));
+    CPPUNIT_ASSERT_EQUAL("av333bthe answer is here"s, base->get_vars()->substitute("a${var1}b${var42}"));
 }
 
+
 void VarsTest::test_vars_env() {
     base->get_config().get_varsdir_option().set(
         std::vector<std::string>{PROJECT_SOURCE_DIR "/test/libdnf5/conf/data/vars"});
@@ -73,6 +77,175 @@ void VarsTest::test_vars_env() {
     // The variables var1 and var2 are defined in the files.
     // However, var1 was also an environment variable. The environment has a higher priority.
     CPPUNIT_ASSERT_EQUAL(
-        std::string("foo0-foo1-foo9-testvar1-testvar2-456"),
+        "foo0-foo1-foo9-testvar1-testvar2-456"s,
         base->get_vars()->substitute("${DNF0}-${DNF1}-${DNF9}-${var1}-${var41}-${var2}"));
 }
+
+
+void VarsTest::test_vars_api() {
+    base->setup();
+    auto vars = base->get_vars();
+
+    CPPUNIT_ASSERT(!vars->contains("test_var1"));
+
+    vars->set("test_var1", "123", libdnf5::Vars::Priority::PLUGIN);
+    CPPUNIT_ASSERT(vars->contains("test_var1"));
+
+    {
+        auto & [value, prioriry] = vars->get("test_var1");
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("value returned by vars->get()", "123"s, value);
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("priority returned by vars->get()", libdnf5::Vars::Priority::PLUGIN, prioriry);
+    }
+
+    CPPUNIT_ASSERT_EQUAL_MESSAGE("value returned by vars->get_value()", "123"s, vars->get_value("test_var1"));
+
+    CPPUNIT_ASSERT(vars->unset("test_var1"));
+    CPPUNIT_ASSERT_MESSAGE("after vars->unset(\"test_var1\")", !vars->contains("test_var1"));
+}
+
+
+void VarsTest::test_vars_api_set_prio() {
+    base->setup();
+    auto vars = base->get_vars();
+
+    CPPUNIT_ASSERT(!vars->contains("test_var1"));
+
+    // set a new variable
+    vars->set("test_var1", "123", libdnf5::Vars::Priority::PLUGIN);
+    {
+        auto & [value, prioriry] = vars->get("test_var1");
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("value returned by vars->get()", "123"s, value);
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("priority returned by vars->get()", libdnf5::Vars::Priority::PLUGIN, prioriry);
+    }
+
+    // change the value using the same priority
+    vars->set("test_var1", "345", libdnf5::Vars::Priority::PLUGIN);
+    {
+        auto & [value, prioriry] = vars->get("test_var1");
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("value returned by vars->get()", "345"s, value);
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("priority returned by vars->get()", libdnf5::Vars::Priority::PLUGIN, prioriry);
+    }
+
+    // change the value using a higher priority
+    vars->set("test_var1", "678", libdnf5::Vars::Priority::COMMANDLINE);
+    {
+        auto & [value, prioriry] = vars->get("test_var1");
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("value returned by vars->get()", "678"s, value);
+        CPPUNIT_ASSERT_EQUAL_MESSAGE(
+            "priority returned by vars->get()", libdnf5::Vars::Priority::COMMANDLINE, prioriry);
+    }
+
+    // changing the value using a lower priority is ignored
+    vars->set("test_var1", "ignored_value", libdnf5::Vars::Priority::PLUGIN);
+    {
+        auto & [value, prioriry] = vars->get("test_var1");
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("value returned by vars->get()", "678"s, value);
+        CPPUNIT_ASSERT_EQUAL_MESSAGE(
+            "priority returned by vars->get()", libdnf5::Vars::Priority::COMMANDLINE, prioriry);
+    }
+
+    // change the value using default priority - default is RUNTIME, the highest priority
+    vars->set("test_var1", "999");
+    {
+        auto & [value, prioriry] = vars->get("test_var1");
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("value returned by vars->get()", "999"s, value);
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("priority returned by vars->get()", libdnf5::Vars::Priority::RUNTIME, prioriry);
+    }
+}
+
+
+void VarsTest::test_vars_api_unset_prio() {
+    base->setup();
+    auto vars = base->get_vars();
+
+    // set a new variable
+    vars->set("test_var1", "123", libdnf5::Vars::Priority::COMMANDLINE);
+    {
+        auto & [value, prioriry] = vars->get("test_var1");
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("value returned by vars->get()", "123"s, value);
+        CPPUNIT_ASSERT_EQUAL_MESSAGE(
+            "priority returned by vars->get()", libdnf5::Vars::Priority::COMMANDLINE, prioriry);
+    }
+
+    // removing a variable using a lower priority is ignored
+    CPPUNIT_ASSERT(!vars->unset("test_var1", libdnf5::Vars::Priority::PLUGIN));
+    CPPUNIT_ASSERT_MESSAGE(
+        "after vars->unset(\"test_var1\", libdnf5::Vars::Priority::PLUGIN)", vars->contains("test_var1"));
+    {
+        auto & [value, prioriry] = vars->get("test_var1");
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("value returned by vars->get()", "123"s, value);
+        CPPUNIT_ASSERT_EQUAL_MESSAGE(
+            "priority returned by vars->get()", libdnf5::Vars::Priority::COMMANDLINE, prioriry);
+    }
+
+    // removing a variable using the same priority
+    CPPUNIT_ASSERT(vars->unset("test_var1", libdnf5::Vars::Priority::COMMANDLINE));
+    CPPUNIT_ASSERT_MESSAGE(
+        "after vars->unset(\"test_var1\", libdnf5::Vars::Priority::COMMANDLINE)", !vars->contains("test_var1"));
+
+
+    // set a new variable
+    vars->set("test_var2", "345", libdnf5::Vars::Priority::PLUGIN);
+    CPPUNIT_ASSERT(vars->contains("test_var2"));
+
+    // removing a variable using a higher priority
+    CPPUNIT_ASSERT(vars->unset("test_var2", libdnf5::Vars::Priority::COMMANDLINE));
+    CPPUNIT_ASSERT_MESSAGE(
+        "after vars->unset(\"test_var2\", libdnf5::Vars::Priority::COMMANDLINE)", !vars->contains("test_var2"));
+
+
+    // set a new variable
+    vars->set("test_var3", "678", libdnf5::Vars::Priority::PLUGIN);
+    CPPUNIT_ASSERT(vars->contains("test_var3"));
+
+    // removing a variable using default priority - default is RUNTIME, the highest priority
+    CPPUNIT_ASSERT(vars->unset("test_var3"));
+    CPPUNIT_ASSERT_MESSAGE("after vars->unset(\"test_var3\")", !vars->contains("test_var3"));
+}
+
+
+void VarsTest::test_vars_api_releasever() {
+    base->setup();
+    auto vars = base->get_vars();
+
+    // set the "releasever" variable
+    vars->set("releasever", "40.12", libdnf5::Vars::Priority::PLUGIN);
+
+    // check the value the of "releasever" variable
+    {
+        auto & [value, prioriry] = vars->get("releasever");
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("value returned by vars->get()", "40.12"s, value);
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("priority returned by vars->get()", libdnf5::Vars::Priority::PLUGIN, prioriry);
+    }
+
+    // check the value the of auto-created read-only variables
+    {
+        auto & [value, prioriry] = vars->get("releasever_major");
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("value returned by vars->get()", "40"s, value);
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("priority returned by vars->get()", libdnf5::Vars::Priority::PLUGIN, prioriry);
+    }
+    {
+        auto & [value, prioriry] = vars->get("releasever_minor");
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("value returned by vars->get()", "12"s, value);
+        CPPUNIT_ASSERT_EQUAL_MESSAGE("priority returned by vars->get()", libdnf5::Vars::Priority::PLUGIN, prioriry);
+    }
+
+    // the "releasever" variable is read-write
+    CPPUNIT_ASSERT(!vars->is_read_only("releasever"));
+
+    // auto-created variables "releasever_major" and "releasever_minor" are read-only
+    CPPUNIT_ASSERT(vars->is_read_only("releasever_major"));
+    CPPUNIT_ASSERT(vars->is_read_only("releasever_minor"));
+
+    // setting the value of a read-only variable throws exception
+    CPPUNIT_ASSERT_THROW(
+        vars->set("releasever_major", "40", libdnf5::Vars::Priority::PLUGIN), libdnf5::ReadOnlyVariableError);
+
+    // removing read-only variable throws exception
+    CPPUNIT_ASSERT_THROW(
+        vars->unset("releasever_major", libdnf5::Vars::Priority::PLUGIN), libdnf5::ReadOnlyVariableError);
+
+    // because the variable "releaver" is read-write, it can be removed
+    CPPUNIT_ASSERT(vars->unset("releasever", libdnf5::Vars::Priority::PLUGIN));
+    CPPUNIT_ASSERT_MESSAGE("after vars->unset(\"test_var3\")", !vars->contains("releasever"));
+}

test/libdnf5/conf/test_vars.hpp

@@ -32,6 +32,10 @@ class VarsTest : public TestCaseFixture {
     CPPUNIT_TEST(test_vars);
     CPPUNIT_TEST(test_vars_multiple_dirs);
     CPPUNIT_TEST(test_vars_env);
+    CPPUNIT_TEST(test_vars_api);
+    CPPUNIT_TEST(test_vars_api_set_prio);
+    CPPUNIT_TEST(test_vars_api_unset_prio);
+    CPPUNIT_TEST(test_vars_api_releasever);
     CPPUNIT_TEST_SUITE_END();
 
 public:
@@ -40,6 +44,10 @@ class VarsTest : public TestCaseFixture {
     void test_vars();
     void test_vars_multiple_dirs();
     void test_vars_env();
+    void test_vars_api();
+    void test_vars_api_set_prio();
+    void test_vars_api_unset_prio();
+    void test_vars_api_releasever();
 
     std::unique_ptr<libdnf5::Base> base;
 };