OFStdIOStream: Add -[hasTerminal]

FossilOrigin-Name: d5eb0384c57e721eaf42d22e7fa08bff9d5473e7455285b7d2f46bc86fcc68e3

Author: Midar

src/OFStdIOStream.h

@@ -53,6 +53,11 @@ OF_SUBCLASSING_RESTRICTED
 	bool _atEndOfStream;
 }
 
+/*!
+ * @brief Whether there is an underlying terminal.
+ */
+@property (readonly, nonatomic) bool hasTerminal;
+
 /*!
  * @brief The number of columns, or -1 if there is no underlying terminal or
  *	  the number of columns could not be queried.

src/OFStdIOStream.m

@@ -386,6 +386,15 @@ - (unsigned int)retainCount
 	return OF_RETAIN_COUNT_MAX;
 }
 
+- (bool)hasTerminal
+{
+#if defined(HAVE_ISATTY) && !defined(OF_AMIGAOS)
+	return isatty(_fd);
+#else
+	return false;
+#endif
+}
+
 - (int)columns
 {
 #if defined(HAVE_SYS_IOCTL_H) && defined(TIOCGWINSZ) && !defined(OF_AMIGAOS)

src/OFWin32ConsoleStdIOStream.m

@@ -456,6 +456,15 @@ - (size_t)lowlevelWriteBuffer: (const void *)buffer_
 	return length;
 }
 
+- (bool)hasTerminal
+{
+	/*
+	 * We can never get here if there is no terminal, as the initializer
+	 * changes the class to OFStdIOStream in that case.
+	 */
+	return true;
+}
+
 - (int)columns
 {
 	CONSOLE_SCREEN_BUFFER_INFO csbi;