Implement INCLUDE_ONCE directive

include/asm/fstack.hpp

@@ -17,6 +17,12 @@
 
 #include "asm/lexer.hpp"
 
+enum IncludeType {
+	INCLUDE_NORMAL,
+	INCLUDE_PRE,
+	INCLUDE_ONCE
+};
+
 struct FileStackNode {
 	FileStackNodeType type;
 	Either<
@@ -64,7 +70,7 @@ void fstk_SetPreIncludeFile(std::string const &path);
 std::optional<std::string> fstk_FindFile(std::string const &path);
 
 bool yywrap();
-void fstk_RunInclude(std::string const &path, bool updateStateNow);
+void fstk_RunInclude(std::string const &path, IncludeType type);
 void fstk_RunMacro(std::string const &macroName, std::shared_ptr<MacroArgs> macroArgs);
 void fstk_RunRept(uint32_t count, int32_t reptLineNo, ContentSpan const &span);
 void fstk_RunFor(

man/rgbasm.5

@@ -2158,7 +2158,17 @@ calls infinitely (or until you run out of memory, whichever comes first).
     INCLUDE "irq.inc"
 .Ed
 .Pp
-You may also implicitly
+You may also ensure a file only gets included once by using
+.Ic INCLUDE_ONCE
+instead of
+.Ic INCLUDE .
+This will skip including a file if it has already been included before (with
+.Ic INCLUDE ,
+.Ic INCLUDE_ONCE ,
+or
+.Fl P ) .
+.Pp
+You can implicitly
 .Ic INCLUDE
 a file before the source file with the
 .Fl P

src/asm/fstack.cpp

@@ -6,9 +6,11 @@
 #include <errno.h>
 #include <inttypes.h>
 #include <memory>
+#include <set>
 #include <stack>
 #include <stdio.h>
 #include <stdlib.h>
+#include <utility>
 
 #include "error.hpp"
 #include "helpers.hpp"
@@ -45,8 +47,8 @@ size_t maxRecursionDepth;
 
 // The first include path for `fstk_FindFile` to try is none at all
 static std::vector<std::string> includePaths = {""};
-
 static std::string preIncludeName;
+static std::set<std::pair<dev_t, ino_t>> includedFiles;
 
 std::string const &FileStackNode::dump(uint32_t curLineNo) const {
 	if (data.holds<std::vector<uint32_t>>()) {
@@ -291,11 +293,11 @@ static Context &newReptContext(int32_t reptLineNo, ContentSpan const &span, uint
 	return context;
 }
 
-void fstk_RunInclude(std::string const &path, bool preInclude) {
+void fstk_RunInclude(std::string const &path, IncludeType type) {
 	std::optional<std::string> fullPath = fstk_FindFile(path);
 
 	if (!fullPath) {
-		if (generatedMissingIncludes && !preInclude) {
+		if (generatedMissingIncludes && type != INCLUDE_PRE) {
 			if (verbose)
 				printf("Aborting (-MG) on INCLUDE file '%s' (%s)\n", path.c_str(), strerror(errno));
 			failedOnMissingInclude = true;
@@ -305,6 +307,24 @@ void fstk_RunInclude(std::string const &path, bool preInclude) {
 		return;
 	}
 
+	// The pair of device ID and serial number uniquely identify a file, with `stat()`
+	// following symbolic links to identify the actual file.
+	struct stat statBuf;
+	if (stat(fullPath->c_str(), &statBuf) != 0) {
+		error("Failed to stat file '%s': %s\n", fullPath->c_str(), strerror(errno));
+		return;
+	}
+	std::pair<dev_t, ino_t> inode{statBuf.st_dev, statBuf.st_ino};
+
+	if (type == INCLUDE_ONCE && includedFiles.find(inode) != includedFiles.end()) {
+		if (verbose) {
+			printf("File '%s' already included, skipping INCLUDE_ONCE", path.c_str());
+		}
+		return;
+	}
+
+	includedFiles.insert(inode);
+
 	if (!newFileContext(*fullPath, false))
 		fatalerror("Failed to set up lexer for file include\n");
 }
@@ -395,5 +415,5 @@ void fstk_Init(std::string const &mainPath, size_t maxDepth) {
 	maxRecursionDepth = maxDepth;
 
 	if (!preIncludeName.empty())
-		fstk_RunInclude(preIncludeName, true);
+		fstk_RunInclude(preIncludeName, INCLUDE_PRE);
 }

src/asm/lexer.cpp

@@ -256,6 +256,7 @@ static std::unordered_map<std::string, int, CaseInsensitive, CaseInsensitive> ke
     {"INCHARMAP",     T_(OP_INCHARMAP)     },
 
     {"INCLUDE",       T_(POP_INCLUDE)      },
+    {"INCLUDE_ONCE",  T_(POP_INCLUDE_ONCE) },
     {"PRINT",         T_(POP_PRINT)        },
     {"PRINTLN",       T_(POP_PRINTLN)      },
     {"EXPORT",        T_(POP_EXPORT)       },

src/asm/parser.y

@@ -236,6 +236,7 @@
 %token POP_IF "IF"
 %token POP_INCBIN "INCBIN"
 %token POP_INCLUDE "INCLUDE"
+%token POP_INCLUDE_ONCE "INCLUDE_ONCE"
 %token POP_LOAD "LOAD"
 %token POP_MACRO "MACRO"
 %token POP_NEWCHARMAP "NEWCHARMAP"
@@ -464,6 +465,7 @@ line_directive:
 	| for
 	| break
 	| include
+	| include_once
 	| if
 	// It's important that all of these require being at line start for `skipIfBlock`
 	| elif
@@ -1140,7 +1142,15 @@ export_def:
 
 include:
 	label POP_INCLUDE string endofline {
-		fstk_RunInclude($3, false);
+		fstk_RunInclude($3, INCLUDE_NORMAL);
+		if (failedOnMissingInclude)
+			YYACCEPT;
+	}
+;
+
+include_once:
+	label POP_INCLUDE_ONCE string endofline {
+		fstk_RunInclude($3, INCLUDE_ONCE);
 		if (failedOnMissingInclude)
 			YYACCEPT;
 	}

test/asm/include-once.asm

@@ -0,0 +1,3 @@
+INCLUDE_ONCE "include-once.inc"
+INCLUDE_ONCE "include-once.inc"
+INCLUDE_ONCE "include-link.inc"

test/asm/include-once.inc

@@ -0,0 +1 @@
+DEF HELLO EQU 1

test/asm/test.sh

@@ -11,9 +11,12 @@ input="$(mktemp)"
 output="$(mktemp)"
 errput="$(mktemp)"
 
+# Create a symbolic link for the `include-once.asm` test case.
+ln include-once.inc include-link.inc
+
 # Immediate expansion is the desired behavior.
 # shellcheck disable=SC2064
-trap "rm -f ${o@Q} ${gb@Q} ${input@Q} ${output@Q} ${errput@Q}" EXIT
+trap "rm -f ${o@Q} ${gb@Q} ${input@Q} ${output@Q} ${errput@Q} include-link.inc" EXIT
 
 tests=0
 failed=0