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, 16 insertions, 22 deletions

diff --git a/src/zen/cmds/print_cmd.cpp b/src/zen/cmds/print_cmd.cpp
index fd6d92f28..c3c11a0ea 100644
--- a/src/zen/cmds/print_cmd.cpp
+++ b/src/zen/cmds/print_cmd.cpp
@@ -55,20 +55,20 @@ PrintCommand::PrintCommand()
 
 PrintCommand::~PrintCommand() = default;
 
-int
+void
 PrintCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
 {
 	ZEN_UNUSED(GlobalOptions);
 
 	if (!ParseOptions(argc, argv))
 	{
-		return 0;
+		return;
 	}
 
 	// Validate arguments
 
 	if (m_Filename.empty())
-		throw std::runtime_error("No file specified");
+		throw OptionParseException("'--source' is required", m_Options.help());
 
 	FileContents Fc;
 
@@ -84,9 +84,7 @@ PrintCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
 
 	if (Fc.ErrorCode)
 	{
-		ZEN_CONSOLE_ERROR("Failed to read file '{}': {}", m_Filename, Fc.ErrorCode.message());
-
-		return 1;
+		throw std::runtime_error(fmt::format("Failed to read file '{}': {}", m_Filename, Fc.ErrorCode.message()));
 	}
 
 	IoBuffer Data = Fc.Flatten();
@@ -158,11 +156,11 @@ PrintCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
 
 		if (FilteredResult != CbValidateError::None)
 		{
-			ZEN_CONSOLE_ERROR("Object in package message file '{}' does not appear to be compact binary (validation error {:#x}: '{}')",
-							  m_Filename,
-							  uint32_t(FilteredResult),
-							  ToString(FilteredResult));
-			return 1;
+			throw std::runtime_error(
+				fmt::format("Object in package message file '{}' does not appear to be compact binary (validation error {:#x}: '{}')",
+							m_Filename,
+							uint32_t(FilteredResult),
+							ToString(FilteredResult)));
 		}
 		else
 		{
@@ -185,18 +183,16 @@ PrintCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
 
 		if (FilteredResult != CbValidateError::None)
 		{
-			ZEN_CONSOLE_ERROR("Data in file '{}' does not appear to be compact binary (validation error {:#x}: '{}')",
-							  m_Filename,
-							  uint32_t(FilteredResult),
-							  ToString(FilteredResult));
-			return 1;
+			throw std::runtime_error(fmt::format("Data in file '{}' does not appear to be compact binary (validation error {:#x}: '{}')",
+												 m_Filename,
+												 uint32_t(FilteredResult),
+												 ToString(FilteredResult)));
 		}
 		else
 		{
 			PrintCompactBinary(Data, m_ShowCbObjectTypeInfo);
 		}
 	}
-	return 0;
 }
 
 //////////////////////////////////////////////////////////////////////////
@@ -218,20 +214,20 @@ PrintPackageCommand::~PrintPackageCommand()
 {
 }
 
-int
+void
 PrintPackageCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** argv)
 {
 	ZEN_UNUSED(GlobalOptions);
 
 	if (!ParseOptions(argc, argv))
 	{
-		return 0;
+		return;
 	}
 
 	// Validate arguments
 
 	if (m_Filename.empty())
-		throw std::runtime_error("No file specified");
+		throw OptionParseException("'--source' is required", m_Options.help());
 
 	MakeSafeAbsolutePathÍnPlace(m_Filename);
 	FileContents Fc	  = ReadFile(m_Filename);
@@ -250,8 +246,6 @@ PrintPackageCommand::Run(const ZenCliOptions& GlobalOptions, int argc, char** ar
 	{
 		ZEN_ERROR("error: malformed package?");
 	}
-
-	return 0;
 }
 
 }  // namespace zen