utils: rework running system commands

Use g_spawn and pass arguments, so we don't involve a shell that needs
escaping etc.

Improve error handling.

lib/utils/mu-test-utils.cc

@@ -115,24 +115,6 @@ Mu::allow_warnings()
 	    {});
 }
 
-
-
-Result<int>
-Mu::run_mu_command(const std::string& args)
-{
-	auto cmdline{mu_format("/bin/sh -c '{} {}'", MU_PROGRAM, args)};
-	if (g_test_verbose())
-		mu_println("command-line: {}", cmdline);
-
-	GError *err{};
-	int wait_status{};
-	if (!g_spawn_command_line_sync(cmdline.c_str(), {}, {}, &wait_status, &err))
-		return Err(Error::Code::File, &err, "failed to execute command '{}", cmdline);
-	else
-		return Ok(WEXITSTATUS(wait_status));
-}
-
-
 Mu::TempDir::TempDir(bool autodelete): autodelete_{autodelete} {
 
 	if (auto res{make_temp_dir()}; !res)

lib/utils/mu-test-utils.hh

@@ -20,6 +20,7 @@
 #ifndef MU_TEST_UTILS_HH__
 #define MU_TEST_UTILS_HH__
 
+#include <initializer_list>
 #include <string>
 #include <utils/mu-utils.hh>
 #include <utils/mu-result.hh>
@@ -91,6 +92,14 @@ bool set_en_us_utf8_locale();
 		}							\
 		} while(0)
 
+#define assert_valid_command(RCO) do {					\
+	assert_valid_result(RCO);					\
+	if ((RCO)->exit_code != 0 && !(RCO)->standard_err.empty())	\
+		mu_printerrln("{}:{}: {}",				\
+			      __FILE__, __LINE__, (RCO)->standard_err);	\
+	g_assert_cmpuint((RCO)->exit_code, ==, 0);			\
+} while (0)
+
 /**
  * For unit-tests, allow warnings in the current function.
  *
@@ -98,18 +107,6 @@ bool set_en_us_utf8_locale();
 void allow_warnings();
 
 
-
-/**
- * Execute the in-tree mu executable with the arguments
- * Asserts if fails.
- *
- * @param args arguments;;
- *
- * @return either the exit code or an error.
- */
-Result<int> run_mu_command(const std::string& args);
-
-
 /**
  * For unit-tests, a RAII tempdir.
  *

lib/utils/mu-utils-file.cc

@@ -277,6 +277,37 @@ Mu::read_from_stdin()
 			g_memory_output_stream_get_size(G_MEMORY_OUTPUT_STREAM(outmem))});
 }
 
+Result<Mu::CommandOutput>
+Mu::run_command(std::initializer_list<std::string> args)
+{
+	std::vector<char*> argvec{};
+	for (auto&& arg: args)
+		argvec.push_back(g_strdup(arg.c_str()));
+	argvec.push_back({});
+
+	GError *err{};
+	int wait_status{};
+	gchar *std_out{}, *std_err{};
+	auto res = g_spawn_sync({},
+				static_cast<char**>(argvec.data()),
+				{},
+				(GSpawnFlags)(G_SPAWN_SEARCH_PATH),
+				{}, {},
+				&std_out, &std_err,
+				&wait_status, &err);
+
+	for (auto& a: argvec)
+		g_free(a);
+
+	if (!res)
+		return Err(Error::Code::File, &err, "failed to execute command");
+	else
+		return Ok(Mu::CommandOutput{
+				WEXITSTATUS(wait_status),
+				to_string_gchar(std::move(std_out/*consumed*/)),
+				to_string_gchar(std::move(std_err/*consumed*/))});
+}
+
 
 #ifdef BUILD_TESTS
 

lib/utils/mu-utils-file.hh

@@ -196,6 +196,22 @@ Result<std::string> make_temp_dir();
 Result<void> remove_directory(const std::string& path);
 
 
+/**
+ * Run some system command
+ *
+ * @param cmd the command
+ *
+ * @return Ok(exit code) or an error. Note that exit-code != 0 is _not_
+ * considered an error from the perspective of this function.
+ */
+struct CommandOutput {
+	int exit_code;
+	std::string standard_out;
+	std::string standard_err;
+};
+Result<CommandOutput> run_command(std::initializer_list<std::string> args);
+
+
 } // namespace Mu
 
 #endif /* MU_UTILS_FILE_HH__ */