Windows/cygwin: no more GetConsoleTitleW errors on XP

src/platform_cygwin.cc

@@ -64,15 +64,21 @@ char** Platform::SetupArgs(int argc, char *argv[]) {
 }
 
 
+// Max title length; the only thing MSDN tells us about the maximum length
+// of the console title is that it is smaller than 64K. However in practice
+// it is much smaller, and there is no way to figure out what the exact length
+// of the title is or can be, at least not on XP. To make it even more
+// annoying, GetConsoleTitle failes when the buffer to be read into is bigger
+// than the actual maximum length. So we make a conservative guess here;
+// just don't put the novel you're writing in the title, unless the plot
+// survives truncation.
+#define MAX_TITLE_LENGTH 8192
+
 void Platform::SetProcessTitle(char *title) {
   // We need to convert _title_ to UTF-16 first, because that's what windows uses internally.
   // It would be more efficient to use the UTF-16 value that we can obtain from v8,
   // but it's not accessible from here.
 
-  // Max title length; according to the specs it should be 64K but in practice it's a little over 30000,
-  // but who needs titles that long anyway?
-  const int MAX_TITLE_LENGTH = 30001;
-
   int length;
   WCHAR *title_w;
 
@@ -109,60 +115,37 @@ void Platform::SetProcessTitle(char *title) {
 
 
 static inline char* _getProcessTitle() {
-  WCHAR *title_w;
+  WCHAR title_w[MAX_TITLE_LENGTH];
   char *title;
-  int length, length_w;
-
-  length_w = GetConsoleTitleW((WCHAR*)L"\0", sizeof(WCHAR));
-
-  // If length is zero, there may be an error or the title may be empty
-  if (!length_w) {
-    if (GetLastError()) {
-      _winapi_perror("GetConsoleTitleW");
-      return NULL;
-    } else {
-      // The title is empty, so return empty string
-      process_title = strdup("\0");
-      return process_title;
-    }
-  }
-
-  // Room for \0 terminator
-  length_w++;
+  int result, length;
 
-  title_w = new WCHAR[length_w];
+  result = GetConsoleTitleW(title_w, sizeof(title_w) / sizeof(WCHAR));
 
-  if (!GetConsoleTitleW(title_w, length_w * sizeof(WCHAR))) {
+  if (result == 0) {
     _winapi_perror("GetConsoleTitleW");
-    delete title_w;
     return NULL;
   }
 
   // Find out what the size of the buffer is that we need
-  length = WideCharToMultiByte(CP_UTF8, 0, title_w, length_w, NULL, 0, NULL, NULL);
+  length = WideCharToMultiByte(CP_UTF8, 0, title_w, -1, NULL, 0, NULL, NULL);
   if (!length) {
     _winapi_perror("WideCharToMultiByte");
-    delete title_w;
     return NULL;
   }
 
   title = (char *) malloc(length);
   if (!title) {
     perror("malloc");
-    delete title_w;
     return NULL;
   }
 
   // Do utf16 -> utf8 conversion here
   if (!WideCharToMultiByte(CP_UTF8, 0, title_w, -1, title, length, NULL, NULL)) {
     _winapi_perror("WideCharToMultiByte");
-    delete title_w;
     free(title);
     return NULL;
   }
 
-  delete title_w;
-
   return title;
 }
 

src/platform_win32.cc

@@ -94,15 +94,21 @@ char** Platform::SetupArgs(int argc, char *argv[]) {
 }
 
 
+// Max title length; the only thing MSDN tells us about the maximum length
+// of the console title is that it is smaller than 64K. However in practice
+// it is much smaller, and there is no way to figure out what the exact length
+// of the title is or can be, at least not on XP. To make it even more
+// annoying, GetConsoleTitle failes when the buffer to be read into is bigger
+// than the actual maximum length. So we make a conservative guess here;
+// just don't put the novel you're writing in the title, unless the plot
+// survives truncation.
+#define MAX_TITLE_LENGTH 8192
+
 void Platform::SetProcessTitle(char *title) {
   // We need to convert _title_ to UTF-16 first, because that's what windows uses internally.
   // It would be more efficient to use the UTF-16 value that we can obtain from v8,
   // but it's not accessible from here.
 
-  // Max title length; according to the specs it should be 64K but in practice it's a little over 30000,
-  // but who needs titles that long anyway?
-  const int MAX_TITLE_LENGTH = 30001;
-
   int length;
   WCHAR *title_w;
 
@@ -139,61 +145,37 @@ void Platform::SetProcessTitle(char *title) {
 
 
 static inline char* _getProcessTitle() {
-  WCHAR *title_w;
+  WCHAR title_w[MAX_TITLE_LENGTH];
   char *title;
-  int length, length_w;
-
-  length_w = GetConsoleTitleW((WCHAR*)L"\0", sizeof(WCHAR));
-
-  // If length is zero, there may be an error or the title may be empty
-  if (!length_w) {
-    if (GetLastError()) {
-      winapi_perror("GetConsoleTitleW");
-      return NULL;
-    }
-    else {
-      // The title is empty, so return empty string
-      process_title = strdup("\0");
-      return process_title;
-    }
-  }
-
-  // Room for \0 terminator
-  length_w++;
+  int result, length;
 
-  title_w = new WCHAR[length_w];
+  result = GetConsoleTitleW(title_w, sizeof(title_w) / sizeof(WCHAR));
 
-  if (!GetConsoleTitleW(title_w, length_w * sizeof(WCHAR))) {
+  if (result == 0) {
     winapi_perror("GetConsoleTitleW");
-    delete title_w;
     return NULL;
   }
 
   // Find out what the size of the buffer is that we need
-  length = WideCharToMultiByte(CP_UTF8, 0, title_w, length_w, NULL, 0, NULL, NULL);
+  length = WideCharToMultiByte(CP_UTF8, 0, title_w, -1, NULL, 0, NULL, NULL);
   if (!length) {
     winapi_perror("WideCharToMultiByte");
-    delete title_w;
     return NULL;
   }
 
   title = (char *) malloc(length);
   if (!title) {
     perror("malloc");
-    delete title_w;
     return NULL;
   }
 
   // Do utf16 -> utf8 conversion here
   if (!WideCharToMultiByte(CP_UTF8, 0, title_w, -1, title, length, NULL, NULL)) {
     winapi_perror("WideCharToMultiByte");
-    delete title_w;
     free(title);
     return NULL;
   }
 
-  delete title_w;
-
   return title;
 }