core: use std::string in error_callback

No naked free().

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

core/errorhelper.cpp

@@ -1,50 +1,44 @@
 // SPDX-License-Identifier: GPL-2.0
-#ifdef __clang__
-// Clang has a bug on zero-initialization of C structs.
-#pragma clang diagnostic ignored "-Wmissing-field-initializers"
-#endif
-#include <stdarg.h>
 #include "errorhelper.h"
-#include "membuffer.h"
+#include "format.h"
+
+#include <stdarg.h>
 
 #if !defined(Q_OS_ANDROID) && !defined(__ANDROID__)
-#define LOG_MSG(fmt, ...)	fprintf(stderr, fmt, ##__VA_ARGS__)
+#define LOG_MSG(fmt, s)	fprintf(stderr, fmt, s)
 #else
 #include <android/log.h>
-#define LOG_MSG(fmt, ...)	__android_log_print(ANDROID_LOG_INFO, "Subsurface", fmt, ##__VA_ARGS__);
+#define LOG_MSG(fmt, s)	__android_log_print(ANDROID_LOG_INFO, "Subsurface", fmt, s);
 #endif
 
-#define VA_BUF(b, fmt) do { va_list args; va_start(args, fmt); put_vformat(b, fmt, args); va_end(args); } while (0)
-
 int verbose;
 
 void report_info(const char *fmt, ...)
 {
-	membuffer buf;
-
-	VA_BUF(&buf, fmt);
-	strip_mb(&buf);
-	LOG_MSG("INFO: %s\n", mb_cstring(&buf));
+	va_list args;
+	va_start(args, fmt);
+	std::string s = vformat_string_std(fmt, args);
+	va_end(args);
+	LOG_MSG("INFO: %s\n", s.c_str());
 }
 
-static void (*error_cb)(char *) = NULL;
+static void (*error_cb)(std::string) = NULL;
 
 int report_error(const char *fmt, ...)
 {
-	membuffer buf;
-
-	VA_BUF(&buf, fmt);
-	strip_mb(&buf);
-	LOG_MSG("ERROR: %s\n", mb_cstring(&buf));
+	va_list args;
+	va_start(args, fmt);
+	std::string s = vformat_string_std(fmt, args);
+	va_end(args);
+	LOG_MSG("ERROR: %s\n", s.c_str());
 
 	/* if there is no error callback registered, don't produce errors */
-	if (!error_cb)
-		return -1;
-	error_cb(detach_cstring(&buf));
+	if (error_cb)
+		error_cb(std::move(s));
 	return -1;
 }
 
-void set_error_cb(void(*cb)(char *))
+void set_error_cb(void(*cb)(std::string))
 {
 	error_cb = cb;
 }

core/errorhelper.h

@@ -4,6 +4,8 @@
 
 // error reporting functions
 
+#include <string>
+
 #ifdef __GNUC__
 #define __printf(x, y) __attribute__((__format__(__printf__, x, y)))
 #else
@@ -13,6 +15,6 @@
 extern int verbose;
 extern int __printf(1, 2) report_error(const char *fmt, ...);
 extern void __printf(1, 2) report_info(const char *fmt, ...);
-extern void set_error_cb(void(*cb)(char *));	// Callback takes ownership of passed string
+extern void set_error_cb(void(*cb)(std::string s));	// Callback takes ownership of passed string
 
 #endif

core/membuffer.cpp

@@ -18,35 +18,17 @@ membuffer::membuffer()
 
 membuffer::~membuffer()
 {
-	free_buffer(this);
-}
-
-/* Only for internal use */
-static char *detach_buffer(struct membuffer *b)
-{
-	char *result = b->buffer;
-	b->buffer = NULL;
-	b->len = 0;
-	b->alloc = 0;
-	return result;
-}
-
-char *detach_cstring(struct membuffer *b)
-{
-	mb_cstring(b);
-	return detach_buffer(b);
-}
-
-void free_buffer(struct membuffer *b)
-{
-	free(detach_buffer(b));
+	free(buffer);
 }
 
 void flush_buffer(struct membuffer *b, FILE *f)
 {
 	if (b->len) {
 		fwrite(b->buffer, 1, b->len, f);
-		free_buffer(b);
+		free(b->buffer);
+		b->buffer = NULL;
+		b->len = 0;
+		b->alloc = 0;
 	}
 }
 

core/membuffer.h

@@ -19,10 +19,6 @@
  *
  *     "something, something else"
  *
- * Unless ownership to the buffer is given away by using "detach_cstring()":
- *
- *	ptr = detach_cstring();
- *
  * where the caller now has a C string and is supposed to free it.
  */
 #ifndef MEMBUFFER_H
@@ -46,8 +42,6 @@ struct membuffer {
 #define __printf(x, y)
 #endif
 
-extern char *detach_cstring(struct membuffer *b);
-extern void free_buffer(struct membuffer *);
 extern void make_room(struct membuffer *b, unsigned int size);
 extern void flush_buffer(struct membuffer *, FILE *);
 extern void put_bytes(struct membuffer *, const char *, int);

desktop-widgets/downloadfromdivecomputer.cpp

@@ -440,12 +440,11 @@ void DownloadFromDCWidget::on_downloadCancelRetryButton_clicked()
 		// this breaks an "else if" across lines... not happy...
 #endif
 	if (data->vendor() == "Uemis") {
-		char *colon;
-		char *devname = copy_qstring(ui.device->currentText());
-
-		if ((colon = strstr(devname, ":\\ (UEMISSDA)")) != NULL) {
-			*(colon + 2) = '\0';
-			report_info("shortened devname to \"%s\"", devname);
+		QString devname = ui.device->currentText();
+		auto colon = devname.indexOf(":\\ (UEMISSDA)");
+		if (colon >= 0) {
+			devname.resize(colon + 2);
+			report_info("shortened devname to \"%s\"", qPrintable(devname));
 		}
 		data->setDevName(devname);
 	} else {

desktop-widgets/mainwindow.cpp

@@ -107,11 +107,9 @@ int updateProgress(const char *text)
 
 MainWindow *MainWindow::m_Instance = nullptr;
 
-void showErrorFromC(char *buf)
+static void showError(std::string err)
 {
-	QString error(buf);
-	free(buf);
-	emit MainWindow::instance()->showError(error);
+	emit MainWindow::instance()->showError(QString::fromStdString(err));
 }
 
 MainWindow::MainWindow() :
@@ -242,7 +240,7 @@ MainWindow::MainWindow() :
 
 	setupSocialNetworkMenu();
 	set_git_update_cb(&updateProgress);
-	set_error_cb(&showErrorFromC);
+	set_error_cb(&::showError);
 
 // full screen support is buggy on Windows and Ubuntu.
 // require the FULLSCREEN_SUPPORT macro to enable it!

mobile-widgets/qmlmanager.cpp

@@ -66,10 +66,9 @@ bool noCloudToCloud = false;
 #define RED_FONT QLatin1String("<font color=\"red\">")
 #define END_FONT QLatin1String("</font>")
 
-void showErrorFromC(char *buf)
+static void showError(std::string s)
 {
-	QString error(buf);
-	free(buf);
+	QString error = QString::fromStdString(s);
 	// By using invokeMethod with Qt:AutoConnection, the error string is safely
 	// transported across thread boundaries, if not called from the UI thread.
 	QMetaObject::invokeMethod(QMLManager::instance(), "registerError", Qt::AutoConnection, Q_ARG(QString, error));
@@ -271,7 +270,7 @@ QMLManager::QMLManager() :
 		appendTextToLog("No writeable location found, in-memory log only and no libdivecomputer log");
 	}
 #endif
-	set_error_cb(&showErrorFromC);
+	set_error_cb(&showError);
 	uiNotificationCallback = showProgress;
 	appendTextToLog("Starting " + getUserAgent());
 	appendTextToLog(QStringLiteral("built with libdivecomputer v%1").arg(dc_version(NULL)));

smtk-import/smrtk2ssrfc_window.cpp

@@ -15,11 +15,9 @@ QStringList inputFiles;
 QString outputFile;
 QString error_buf;
 
-void getErrorFromC(char *buf)
+void getErrorFromC(std::string buf)
 {
-	QString error(buf);
-	free(buf);
-	error_buf = error;
+	error_buf = QString::fromStdString(std::move(buf));
 }
 
 Smrtk2ssrfcWindow::Smrtk2ssrfcWindow(QWidget *parent) :