refactor zen command return value handling (#487)

- Improvement: Use consistent language for command line argument parsing errors
- Improvement: Changed zen command parsing errors to output help first and error last to make it easier to spot the error
- Improvement: Refactor zen command return codes to conform to valid Linux range (0-255)

        kSuccess     = 0,
        kOtherError  = 1,
        kBadInput    = 2,

        kOutOfMemory = 16,
        kOutOfDisk   = 17,

        kAssertError = 70,
        
        kHttpOtherClientError = 80,
        kHttpCantConnectError = 81,
        kHttpNotFound         = 66,  // NotFound(404)
        kHttpUnauthorized     = 77,  // Unauthorized(401),
        kHttpSLLError         = 82,
        kHttpForbidden        = 83,  // Forbidden(403)
        kHttpTimeout          = 84,  // RequestTimeout(408)
        kHttpConflict         = 85,  // Conflict(409)
        kHttpNoHost           = 86,
        
        kHttpOtherServerError	   = 90,
        kHttpInternalServerError = 91,  // InternalServerError(500)
        kHttpServiceUnavailable  = 69,  // ServiceUnavailable(503)
        kHttpBadGateway          = 92,  // BadGateway(502)
        kHttpGatewayTimeout      = 93,  // GatewayTimeout(504)

1 files changed, 5 insertions, 13 deletions

diff --git a/src/zen/cmds/vfs_cmd.cpp b/src/zen/cmds/vfs_cmd.cpp
index e8802d990..79ec20ce2 100644
--- a/src/zen/cmds/vfs_cmd.cpp
+++ b/src/zen/cmds/vfs_cmd.cpp
@@ -28,14 +28,14 @@ VfsCommand::~VfsCommand()
 {
 }
 
-int
+void
 VfsCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
 {
 	ZEN_UNUSED(GlobalOptions, argc, argv);
 
-	if (!ZenCmdBase::ParseOptions(argc, argv))
+	if (!ParseOptions(argc, argv))
 	{
-		return 0;
+		return;
 	}
 
 	// Validate arguments
@@ -43,14 +43,14 @@ VfsCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
 	m_HostName = ResolveTargetHostSpec(m_HostName);
 
 	if (m_HostName.empty())
-		throw OptionParseException("unable to resolve server specification");
+		throw OptionParseException("Unable to resolve server specification", m_Options.help());
 
 	HttpClient Http(m_HostName);
 
 	if (m_Verb == "mount"sv)
 	{
 		if (m_MountPath.empty())
-			throw OptionParseException("No source specified");
+			throw OptionParseException("'--vfs-path' is required", m_Options.help());
 
 		CbObjectWriter Cbo;
 		Cbo << "method"
@@ -66,8 +66,6 @@ VfsCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
 		else
 		{
 			Result.ThrowError("VFS mount request failed"sv);
-
-			return 1;
 		}
 	}
 	else if (m_Verb == "unmount"sv)
@@ -82,8 +80,6 @@ VfsCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
 		else
 		{
 			Result.ThrowError("VFS unmount request failed"sv);
-
-			return 1;
 		}
 	}
 	else if (m_Verb == "info"sv)
@@ -97,12 +93,8 @@ VfsCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
 		else
 		{
 			Result.ThrowError("VFS info fetch failed"sv);
-
-			return 1;
 		}
 	}
-
-	return 0;
 }
 
 }  // namespace zen