Simplify fstk_FindFile usage (#1310)

* Simplify `fstk_FindFile` usage

* Use `std::string` for `fstk_FindFile`

include/asm/fstack.hpp

@@ -8,6 +8,7 @@
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
+#include <string>
 
 #include "asm/lexer.hpp"
 
@@ -52,12 +53,9 @@ void fstk_AddIncludePath(char const *s);
 void fstk_SetPreIncludeFile(char const *s);
 /*
  * @param path The user-provided file name
- * @param fullPath The address of a pointer, which will be made to point at the full path
- *                 The pointer's value must be a valid argument to `realloc`, including NULL
- * @param size Current size of the buffer, or 0 if the pointer is NULL
- * @return True if the file was found, false if no path worked
+ * @return A pointer to the `new`-allocated full path, or NULL if no path worked
  */
-bool fstk_FindFile(char const *path, char **fullPath, size_t *size);
+std::string *fstk_FindFile(char const *path);
 
 bool yywrap(void);
 void fstk_RunInclude(char const *path);

src/asm/fstack.cpp

@@ -4,9 +4,11 @@
 #include <assert.h>
 #include <errno.h>
 #include <inttypes.h>
+#include <new>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string>
 
 #include "asm/fstack.hpp"
 #include "asm/macro.hpp"
@@ -159,47 +161,20 @@ static bool isPathValid(char const *path)
 	return !S_ISDIR(statbuf.st_mode);
 }
 
-bool fstk_FindFile(char const *path, char **fullPath, size_t *size)
+std::string *fstk_FindFile(char const *path)
 {
-	if (!*size) {
-		*size = 64; // This is arbitrary, really
-		*fullPath = (char *)realloc(*fullPath, *size);
-		if (!*fullPath)
-			error("realloc error during include path search: %s\n",
-			      strerror(errno));
-	}
+	std::string *fullPath = new(std::nothrow) std::string();
 
-	if (*fullPath) {
+	if (!fullPath) {
+		error("Failed to allocate string during include path search: %s\n", strerror(errno));
+	} else {
 		for (size_t i = 0; i <= nbIncPaths; ++i) {
-			char const *incPath = i ? includePaths[i - 1] : "";
-			int len = snprintf(*fullPath, *size, "%s%s", incPath, path);
+			*fullPath = i ? includePaths[i - 1] : "";
+			*fullPath += path;
 
-			if (len < 0) {
-				error("snprintf error during include path search: %s\n",
-				      strerror(errno));
-				break;
-			}
-
-			// Oh how I wish `asnprintf` was standard...
-			if ((size_t)len >= *size) { // `size` includes the terminator, `len` doesn't
-				*size = len + 1;
-				*fullPath = (char *)realloc(*fullPath, *size);
-				if (!*fullPath) {
-					error("realloc error during include path search: %s\n",
-					      strerror(errno));
-					break;
-				}
-				len = sprintf(*fullPath, "%s%s", incPath, path);
-				if (len < 0) {
-					error("sprintf error during include path search: %s\n",
-					       strerror(errno));
-					break;
-				}
-			}
-
-			if (isPathValid(*fullPath)) {
-				printDep(*fullPath);
-				return true;
+			if (isPathValid(fullPath->c_str())) {
+				printDep(fullPath->c_str());
+				return fullPath;
 			}
 		}
 	}
@@ -207,7 +182,7 @@ bool fstk_FindFile(char const *path, char **fullPath, size_t *size)
 	errno = ENOENT;
 	if (generatedMissingIncludes)
 		printDep(path);
-	return false;
+	return NULL;
 }
 
 bool yywrap(void)
@@ -320,11 +295,9 @@ static void newContext(struct FileStackNode *fileInfo)
 
 void fstk_RunInclude(char const *path)
 {
-	char *fullPath = NULL;
-	size_t size = 0;
+	std::string *fullPath = fstk_FindFile(path);
 
-	if (!fstk_FindFile(path, &fullPath, &size)) {
-		free(fullPath);
+	if (!fullPath) {
 		if (generatedMissingIncludes) {
 			if (verbose)
 				printf("Aborting (-MG) on INCLUDE file '%s' (%s)\n",
@@ -337,15 +310,15 @@ void fstk_RunInclude(char const *path)
 	}
 
 	struct FileStackNamedNode *fileInfo =
-		(struct FileStackNamedNode *)malloc(sizeof(*fileInfo) + size);
+		(struct FileStackNamedNode *)malloc(sizeof(*fileInfo) + fullPath->length() + 1);
 
 	if (!fileInfo) {
 		error("Failed to alloc file info for INCLUDE: %s\n", strerror(errno));
 		return;
 	}
 	fileInfo->node.type = NODE_FILE;
-	strcpy(fileInfo->name, fullPath);
-	free(fullPath);
+	strcpy(fileInfo->name, fullPath->c_str());
+	delete fullPath;
 
 	newContext((struct FileStackNode *)fileInfo);
 	contextStack->lexerState = lexer_OpenFile(fileInfo->name);
@@ -365,25 +338,23 @@ static void runPreIncludeFile(void)
 	if (!preIncludeName)
 		return;
 
-	char *fullPath = NULL;
-	size_t size = 0;
+	std::string *fullPath = fstk_FindFile(preIncludeName);
 
-	if (!fstk_FindFile(preIncludeName, &fullPath, &size)) {
-		free(fullPath);
+	if (!fullPath) {
 		error("Unable to open included file '%s': %s\n", preIncludeName, strerror(errno));
 		return;
 	}
 
 	struct FileStackNamedNode *fileInfo =
-		(struct FileStackNamedNode *)malloc(sizeof(*fileInfo) + size);
+		(struct FileStackNamedNode *)malloc(sizeof(*fileInfo) + fullPath->length() + 1);
 
 	if (!fileInfo) {
 		error("Failed to alloc file info for pre-include: %s\n", strerror(errno));
 		return;
 	}
 	fileInfo->node.type = NODE_FILE;
-	strcpy(fileInfo->name, fullPath);
-	free(fullPath);
+	strcpy(fileInfo->name, fullPath->c_str());
+	delete fullPath;
 
 	newContext((struct FileStackNode *)fileInfo);
 	contextStack->lexerState = lexer_OpenFile(fileInfo->name);

src/asm/section.cpp

@@ -7,6 +7,7 @@
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string>
 #include <string.h>
 
 #include "asm/fstack.hpp"
@@ -807,13 +808,10 @@ void sect_BinaryFile(char const *s, int32_t startPos)
 	if (!checkcodesection())
 		return;
 
-	char *fullPath = NULL;
-	size_t size = 0;
-	FILE *f = NULL;
+	std::string *fullPath = fstk_FindFile(s);
+	FILE *f = fullPath ? fopen(fullPath->c_str(), "rb") : NULL;
 
-	if (fstk_FindFile(s, &fullPath, &size))
-		f = fopen(fullPath, "rb");
-	free(fullPath);
+	delete fullPath;
 
 	if (!f) {
 		if (generatedMissingIncludes) {
@@ -881,13 +879,10 @@ void sect_BinaryFileSlice(char const *s, int32_t start_pos, int32_t length)
 	if (!reserveSpace(length))
 		return;
 
-	char *fullPath = NULL;
-	size_t size = 0;
-	FILE *f = NULL;
+	std::string *fullPath = fstk_FindFile(s);
+	FILE *f = fullPath ? fopen(fullPath->c_str(), "rb") : NULL;
 
-	if (fstk_FindFile(s, &fullPath, &size))
-		f = fopen(fullPath, "rb");
-	free(fullPath);
+	delete fullPath;
 
 	if (!f) {
 		if (generatedMissingIncludes) {