introduce CopyFormat refactor CopyFormatOptions

Currently, COPY command format is determined by two booleans, binary and
csv_mode, within CopyFormatOptions. This approach, while functional, isn't ideal
for future expansion.

To simplify adding new formats, we've introduced an enum CopyFormat.  This makes
the code cleaner and more maintainable, allowing for easier integration of
additional formats down the line.

The CopyFormat enum was originally contributed by Joel Jacobson
[email protected], later refactored by Jian He to address various issues.

discussion: https://postgr.es/m/CALvfUkBxTYy5uWPFVwpk_7ii2zgT07t3d-yR_cy4sfrrLU%3Dkcg%40mail.gmail.com
discussion: https://postgr.es/m/[email protected]

Author: jianhe-fun

src/backend/commands/copy.c

@@ -564,6 +564,8 @@ ProcessCopyOptions(ParseState *pstate,
 		opts_out = (CopyFormatOptions *) palloc0(sizeof(CopyFormatOptions));
 
 	opts_out->file_encoding = -1;
+	/* default format */
+	opts_out->format = COPY_FORMAT_TEXT;
 
 	/* Extract options from the statement node tree */
 	foreach(option, options)
@@ -578,11 +580,11 @@ ProcessCopyOptions(ParseState *pstate,
 				errorConflictingDefElem(defel, pstate);
 			format_specified = true;
 			if (strcmp(fmt, "text") == 0)
-				 /* default format */ ;
+				opts_out->format = COPY_FORMAT_TEXT;
 			else if (strcmp(fmt, "csv") == 0)
-				opts_out->csv_mode = true;
+				opts_out->format = COPY_FORMAT_CSV;
 			else if (strcmp(fmt, "binary") == 0)
-				opts_out->binary = true;
+				opts_out->format = COPY_FORMAT_BINARY;
 			else
 				ereport(ERROR,
 						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
@@ -742,31 +744,31 @@ ProcessCopyOptions(ParseState *pstate,
 	 * Check for incompatible options (must do these three before inserting
 	 * defaults)
 	 */
-	if (opts_out->binary && opts_out->delim)
+	if (opts_out->format == COPY_FORMAT_BINARY && opts_out->delim)
 		ereport(ERROR,
 				(errcode(ERRCODE_SYNTAX_ERROR),
 		/*- translator: %s is the name of a COPY option, e.g. ON_ERROR */
 				 errmsg("cannot specify %s in BINARY mode", "DELIMITER")));
 
-	if (opts_out->binary && opts_out->null_print)
+	if (opts_out->format == COPY_FORMAT_BINARY && opts_out->null_print)
 		ereport(ERROR,
 				(errcode(ERRCODE_SYNTAX_ERROR),
 				 errmsg("cannot specify %s in BINARY mode", "NULL")));
 
-	if (opts_out->binary && opts_out->default_print)
+	if (opts_out->format == COPY_FORMAT_BINARY && opts_out->default_print)
 		ereport(ERROR,
 				(errcode(ERRCODE_SYNTAX_ERROR),
 				 errmsg("cannot specify %s in BINARY mode", "DEFAULT")));
 
 	/* Set defaults for omitted options */
 	if (!opts_out->delim)
-		opts_out->delim = opts_out->csv_mode ? "," : "\t";
+		opts_out->delim = (opts_out->format == COPY_FORMAT_CSV) ? "," : "\t";
 
 	if (!opts_out->null_print)
-		opts_out->null_print = opts_out->csv_mode ? "" : "\\N";
+		opts_out->null_print = (opts_out->format == COPY_FORMAT_CSV) ? "" : "\\N";
 	opts_out->null_print_len = strlen(opts_out->null_print);
 
-	if (opts_out->csv_mode)
+	if (opts_out->format == COPY_FORMAT_CSV)
 	{
 		if (!opts_out->quote)
 			opts_out->quote = "\"";
@@ -814,51 +816,51 @@ ProcessCopyOptions(ParseState *pstate,
 	 * future-proofing.  Likewise we disallow all digits though only octal
 	 * digits are actually dangerous.
 	 */
-	if (!opts_out->csv_mode &&
+	if (opts_out->format != COPY_FORMAT_CSV &&
 		strchr("\\.abcdefghijklmnopqrstuvwxyz0123456789",
 			   opts_out->delim[0]) != NULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("COPY delimiter cannot be \"%s\"", opts_out->delim)));
 
 	/* Check header */
-	if (opts_out->binary && opts_out->header_line != COPY_HEADER_FALSE)
+	if (opts_out->format == COPY_FORMAT_BINARY && opts_out->header_line != COPY_HEADER_FALSE)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 		/*- translator: %s is the name of a COPY option, e.g. ON_ERROR */
 				 errmsg("cannot specify %s in BINARY mode", "HEADER")));
 
 	/* Check quote */
-	if (!opts_out->csv_mode && opts_out->quote != NULL)
+	if (opts_out->format != COPY_FORMAT_CSV && opts_out->quote != NULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 		/*- translator: %s is the name of a COPY option, e.g. ON_ERROR */
 				 errmsg("COPY %s requires CSV mode", "QUOTE")));
 
-	if (opts_out->csv_mode && strlen(opts_out->quote) != 1)
+	if (opts_out->format == COPY_FORMAT_CSV && strlen(opts_out->quote) != 1)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("COPY quote must be a single one-byte character")));
 
-	if (opts_out->csv_mode && opts_out->delim[0] == opts_out->quote[0])
+	if (opts_out->format == COPY_FORMAT_CSV && opts_out->delim[0] == opts_out->quote[0])
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("COPY delimiter and quote must be different")));
 
 	/* Check escape */
-	if (!opts_out->csv_mode && opts_out->escape != NULL)
+	if (opts_out->format != COPY_FORMAT_CSV && opts_out->escape != NULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 		/*- translator: %s is the name of a COPY option, e.g. ON_ERROR */
 				 errmsg("COPY %s requires CSV mode", "ESCAPE")));
 
-	if (opts_out->csv_mode && strlen(opts_out->escape) != 1)
+	if (opts_out->format == COPY_FORMAT_CSV && strlen(opts_out->escape) != 1)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("COPY escape must be a single one-byte character")));
 
 	/* Check force_quote */
-	if (!opts_out->csv_mode && (opts_out->force_quote || opts_out->force_quote_all))
+	if (opts_out->format != COPY_FORMAT_CSV && (opts_out->force_quote || opts_out->force_quote_all))
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 		/*- translator: %s is the name of a COPY option, e.g. ON_ERROR */
@@ -872,8 +874,8 @@ ProcessCopyOptions(ParseState *pstate,
 						"COPY FROM")));
 
 	/* Check force_notnull */
-	if (!opts_out->csv_mode && (opts_out->force_notnull != NIL ||
-								opts_out->force_notnull_all))
+	if (opts_out->format != COPY_FORMAT_CSV && (opts_out->force_notnull != NIL ||
+												opts_out->force_notnull_all))
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 		/*- translator: %s is the name of a COPY option, e.g. ON_ERROR */
@@ -888,8 +890,8 @@ ProcessCopyOptions(ParseState *pstate,
 						"COPY TO")));
 
 	/* Check force_null */
-	if (!opts_out->csv_mode && (opts_out->force_null != NIL ||
-								opts_out->force_null_all))
+	if (opts_out->format != COPY_FORMAT_CSV && (opts_out->force_null != NIL ||
+												opts_out->force_null_all))
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 		/*- translator: %s is the name of a COPY option, e.g. ON_ERROR */
@@ -913,7 +915,7 @@ ProcessCopyOptions(ParseState *pstate,
 						"NULL")));
 
 	/* Don't allow the CSV quote char to appear in the null string. */
-	if (opts_out->csv_mode &&
+	if (opts_out->format == COPY_FORMAT_CSV &&
 		strchr(opts_out->null_print, opts_out->quote[0]) != NULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
@@ -949,7 +951,7 @@ ProcessCopyOptions(ParseState *pstate,
 							"DEFAULT")));
 
 		/* Don't allow the CSV quote char to appear in the default string. */
-		if (opts_out->csv_mode &&
+		if (opts_out->format == COPY_FORMAT_CSV &&
 			strchr(opts_out->default_print, opts_out->quote[0]) != NULL)
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
@@ -966,7 +968,7 @@ ProcessCopyOptions(ParseState *pstate,
 					 errmsg("NULL specification and DEFAULT specification cannot be the same")));
 	}
 	/* Check on_error */
-	if (opts_out->binary && opts_out->on_error != COPY_ON_ERROR_STOP)
+	if (opts_out->format == COPY_FORMAT_BINARY && opts_out->on_error != COPY_ON_ERROR_STOP)
 		ereport(ERROR,
 				(errcode(ERRCODE_SYNTAX_ERROR),
 				 errmsg("only ON_ERROR STOP is allowed in BINARY mode")));

src/backend/commands/copyfrom.c

@@ -155,9 +155,9 @@ static const CopyFromRoutine CopyFromRoutineBinary = {
 static const CopyFromRoutine *
 CopyFromGetRoutine(const CopyFormatOptions *opts)
 {
-	if (opts->csv_mode)
+	if (opts->format == COPY_FORMAT_CSV)
 		return &CopyFromRoutineCSV;
-	else if (opts->binary)
+	else if (opts->format == COPY_FORMAT_BINARY)
 		return &CopyFromRoutineBinary;
 
 	/* default is text */
@@ -261,7 +261,7 @@ CopyFromErrorCallback(void *arg)
 				   cstate->cur_relname);
 		return;
 	}
-	if (cstate->opts.binary)
+	if (cstate->opts.format == COPY_FORMAT_BINARY)
 	{
 		/* can't usefully display the data */
 		if (cstate->cur_attname)

src/backend/commands/copyfromparse.c

@@ -171,7 +171,7 @@ ReceiveCopyBegin(CopyFromState cstate)
 {
 	StringInfoData buf;
 	int			natts = list_length(cstate->attnumlist);
-	int16		format = (cstate->opts.binary ? 1 : 0);
+	int16		format = (cstate->opts.format == COPY_FORMAT_BINARY ? 1 : 0);
 	int			i;
 
 	pq_beginmessage(&buf, PqMsg_CopyInResponse);
@@ -747,7 +747,7 @@ bool
 NextCopyFromRawFields(CopyFromState cstate, char ***fields, int *nfields)
 {
 	return NextCopyFromRawFieldsInternal(cstate, fields, nfields,
-										 cstate->opts.csv_mode);
+										 cstate->opts.format == COPY_FORMAT_CSV);
 }
 
 /*
@@ -774,7 +774,8 @@ NextCopyFromRawFieldsInternal(CopyFromState cstate, char ***fields, int *nfields
 	bool		done = false;
 
 	/* only available for text or csv input */
-	Assert(!cstate->opts.binary);
+	Assert(cstate->opts.format == COPY_FORMAT_TEXT ||
+		   cstate->opts.format == COPY_FORMAT_CSV);
 
 	/* on input check that the header line is correct if needed */
 	if (cstate->cur_lineno == 0 && cstate->opts.header_line != COPY_HEADER_FALSE)

src/backend/commands/copyto.c

@@ -181,9 +181,9 @@ static const CopyToRoutine CopyToRoutineBinary = {
 static const CopyToRoutine *
 CopyToGetRoutine(const CopyFormatOptions *opts)
 {
-	if (opts->csv_mode)
+	if (opts->format == COPY_FORMAT_CSV)
 		return &CopyToRoutineCSV;
-	else if (opts->binary)
+	else if (opts->format == COPY_FORMAT_BINARY)
 		return &CopyToRoutineBinary;
 
 	/* default is text */
@@ -220,7 +220,7 @@ CopyToTextLikeStart(CopyToState cstate, TupleDesc tupDesc)
 
 			colname = NameStr(TupleDescAttr(tupDesc, attnum - 1)->attname);
 
-			if (cstate->opts.csv_mode)
+			if (cstate->opts.format == COPY_FORMAT_CSV)
 				CopyAttributeOutCSV(cstate, colname, false);
 			else
 				CopyAttributeOutText(cstate, colname);
@@ -397,7 +397,7 @@ SendCopyBegin(CopyToState cstate)
 {
 	StringInfoData buf;
 	int			natts = list_length(cstate->attnumlist);
-	int16		format = (cstate->opts.binary ? 1 : 0);
+	int16		format = (cstate->opts.format == COPY_FORMAT_BINARY ? 1 : 0);
 	int			i;
 
 	pq_beginmessage(&buf, PqMsg_CopyOutResponse);

src/include/commands/copy.h

@@ -48,6 +48,16 @@ typedef enum CopyLogVerbosityChoice
 	COPY_LOG_VERBOSITY_VERBOSE, /* logs additional messages */
 } CopyLogVerbosityChoice;
 
+/*
+ * Represents the format of the COPY operation.
+ */
+typedef enum CopyFormat
+{
+	COPY_FORMAT_TEXT = 0,
+	COPY_FORMAT_BINARY,
+	COPY_FORMAT_CSV,
+} CopyFormat;
+
 /*
  * A struct to hold COPY options, in a parsed form. All of these are related
  * to formatting, except for 'freeze', which doesn't really belong here, but
@@ -58,9 +68,8 @@ typedef struct CopyFormatOptions
 	/* parameters from the COPY command */
 	int			file_encoding;	/* file or remote side's character encoding,
 								 * -1 if not specified */
-	bool		binary;			/* binary format? */
+	CopyFormat	format;			/* format of the COPY operation */
 	bool		freeze;			/* freeze rows on loading? */
-	bool		csv_mode;		/* Comma Separated Value format? */
 	int			header_line;	/* number of lines to skip or COPY_HEADER_XXX
 								 * value (see the above) */
 	char	   *null_print;		/* NULL marker string (server encoding!) */

src/tools/pgindent/typedefs.list

@@ -516,6 +516,7 @@ ConversionLocation
 ConvertRowtypeExpr
 CookedConstraint
 CopyDest
+CopyFormat
 CopyFormatOptions
 CopyFromRoutine
 CopyFromState