feat: add an executable for expanding slash commands to SQL

src/bin/psql/.gitignore

@@ -3,4 +3,5 @@
 /sql_help.h
 /sql_help.c
 /psql
+/slash2sql
 /tmp_check/

src/bin/psql/Makefile

@@ -43,12 +43,34 @@ OBJS = \
 	tab-complete.o \
 	variables.o
 
+SQLCMD_OBJS = \
+	$(WIN32RES) \
+	slash2sql.o \
+	command.o \
+	common.o \
+	copy.o \
+	crosstabview.o \
+	describe.o \
+	help.o \
+	input.o \
+	large_obj.o \
+	mainloop.o \
+	prompt.o \
+	psqlscanslash.o \
+	sql_help.o \
+	stringutils.o \
+	tab-complete.o \
+	variables.o
 
-all: psql
+
+all: psql slash2sql
 
 psql: $(OBJS) | submake-libpq submake-libpgport submake-libpgfeutils
 	$(CC) $(CFLAGS) $(OBJS) $(LDFLAGS) $(LDFLAGS_EX) $(LIBS) -o $@$(X)
 
+slash2sql: $(SQLCMD_OBJS) | submake-libpq submake-libpgport submake-libpgfeutils
+	$(CC) $(CFLAGS) $(SQLCMD_OBJS) $(LDFLAGS) $(LDFLAGS_EX) $(LIBS) -o $@$(X)
+
 help.o: sql_help.h
 
 # See notes in src/backend/parser/Makefile about the following two rules
@@ -66,16 +88,17 @@ tab-complete.c: gen_tabcomplete.pl tab-complete.in.c
 
 install: all installdirs
 	$(INSTALL_PROGRAM) psql$(X) '$(DESTDIR)$(bindir)/psql$(X)'
+	$(INSTALL_PROGRAM) slash2sql$(X) '$(DESTDIR)$(bindir)/slash2sql$(X)'
 	$(INSTALL_DATA) $(srcdir)/psqlrc.sample '$(DESTDIR)$(datadir)/psqlrc.sample'
 
 installdirs:
 	$(MKDIR_P) '$(DESTDIR)$(bindir)' '$(DESTDIR)$(datadir)'
 
 uninstall:
-	rm -f '$(DESTDIR)$(bindir)/psql$(X)' '$(DESTDIR)$(datadir)/psqlrc.sample'
+	rm -f '$(DESTDIR)$(bindir)/psql$(X)' '$(DESTDIR)$(bindir)/slash2sql$(X)' '$(DESTDIR)$(datadir)/psqlrc.sample'
 
 clean distclean:
-	rm -f psql$(X) $(OBJS) lex.backup
+	rm -f psql$(X) slash2sql$(X) $(OBJS) $(SQLCMD_OBJS) lex.backup
 	rm -rf tmp_check
 	rm -f sql_help.h sql_help.c psqlscanslash.c tab-complete.c
 

src/bin/psql/slash2sql.c

@@ -0,0 +1,83 @@
+/*
+ * slash2sql - expand slash commands into SQL
+ *
+ * src/bin/psql/slash2sql.c
+ */
+#include "postgres_fe.h"
+#include "command.h"
+#include "common.h"
+#include "common/logging.h"
+#include "mainloop.h"
+#include "settings.h"
+#include "libpq-int.h"
+
+/* Global psql options */
+PsqlSettings pset;
+
+/*
+ * Main entry point
+ */
+int main(int argc, char *argv[])
+{
+	char *cmd = NULL;
+	int successResult;
+	memset(&pset, 0, sizeof(pset));
+
+	// Disable query execution
+	pset.echo_hidden = PSQL_ECHO_HIDDEN_NOEXEC;
+	// Create a fake/empty connection object
+	pset.db = (PGconn *)malloc(sizeof(PGconn));
+	memset(pset.db, 0, sizeof(PGconn));
+
+	// extract the command as the first argument
+	if (argc > 1 && argv[1][0] == '\\')
+	{
+		cmd = pg_strdup(argv[1] + 1);
+	}
+
+	/* If a command was provided via command line, execute it and exit */
+	if (cmd != NULL && strlen(cmd) > 0)
+	{
+		PsqlScanState scan_state;
+		ConditionalStack cond_stack;
+		PQExpBuffer query_buf;
+		PQExpBuffer previous_buf;
+
+		/* Initialize scan state */
+		scan_state = psql_scan_create(&psqlscan_callbacks);
+		cond_stack = conditional_stack_create();
+		psql_scan_set_passthrough(scan_state, cond_stack);
+
+		/* Initialize query buffers */
+		query_buf = createPQExpBuffer();
+		previous_buf = createPQExpBuffer();
+
+		/* Set up scan state */
+		psql_scan_setup(scan_state, cmd, strlen(cmd), 0, standard_strings());
+
+		// Convert to SQL and output
+		HandleSlashCmds(scan_state, cond_stack, query_buf, previous_buf);
+
+		// Clean up
+		psql_scan_destroy(scan_state);
+		conditional_stack_destroy(cond_stack);
+		destroyPQExpBuffer(query_buf);
+		destroyPQExpBuffer(previous_buf);
+
+		// HandleSlashCmds always returns PSQL_CMD_ERROR when execution is disabled
+		successResult = EXIT_SUCCESS;
+	}
+	else
+	{
+		pg_log_error("invalid command");
+		successResult = EXIT_FAILURE;
+	}
+
+	/* Clean up */
+	if (pset.db)
+		free(pset.db);
+	if (cmd)
+		free(cmd);
+
+	return successResult;
+}