winansi: code shrink

Use INVALID_HANDLE_VALUE (not NULL) to indicate that the console and
console_in handles haven't been initialised.

Replace many explicit comparisons against INVALID_HANDLE_VALUE with
tests on the return value of GetConsoleScreenBufferInfo() which
fails for an invalid handle.

1 files changed, 17 insertions, 46 deletions

diff --git a/win32/winansi.c b/win32/winansi.c
index 098b57c5d..a2c49b7e7 100644
--- a/win32/winansi.c
+++ b/win32/winansi.c
@@ -21,15 +21,8 @@
 #undef read
 #undef getc
 
-/*
- ANSI codes used by git: m, K
-
- This file is git-specific. Therefore, this file does not attempt
- to implement any codes that are not used by git.
-*/
-
-static HANDLE console;
-static HANDLE console_in;
+static HANDLE console = INVALID_HANDLE_VALUE;
+static HANDLE console_in = INVALID_HANDLE_VALUE;
 static WORD plain_attr;
 static WORD attr;
 static int negative;
@@ -38,38 +31,28 @@ static void init(void)
 {
         CONSOLE_SCREEN_BUFFER_INFO sbi;
 
-        static int initialized = 0;
-        if (initialized)
+        if (console != INVALID_HANDLE_VALUE || console_in != INVALID_HANDLE_VALUE)
                 return;
 
-        console_in = GetStdHandle(STD_INPUT_HANDLE);
-        if (console_in == INVALID_HANDLE_VALUE)
-                console_in = NULL;
-
         console = GetStdHandle(STD_OUTPUT_HANDLE);
-        if (console == INVALID_HANDLE_VALUE)
-                console = NULL;
-
-        if (!console)
-                return;
-
-        GetConsoleScreenBufferInfo(console, &sbi);
-        attr = plain_attr = sbi.wAttributes;
-        negative = 0;
+        console_in = GetStdHandle(STD_INPUT_HANDLE);
 
-        initialized = 1;
+        if (GetConsoleScreenBufferInfo(console, &sbi)) {
+                attr = plain_attr = sbi.wAttributes;
+                negative = 0;
+        }
 }
 
 static int is_console(int fd)
 {
         init();
-        return isatty(fd) && console;
+        return isatty(fd) && console != INVALID_HANDLE_VALUE;
 }
 
 static int is_console_in(int fd)
 {
         init();
-        return isatty(fd) && console_in;
+        return isatty(fd) && console_in != INVALID_HANDLE_VALUE;
 }
 
 static int skip_ansi_emulation(void)
@@ -126,10 +109,8 @@ static void erase_in_line(void)
         CONSOLE_SCREEN_BUFFER_INFO sbi;
         DWORD dummy; /* Needed for Windows 7 (or Vista) regression */
 
-        if (!console)
+        if (!GetConsoleScreenBufferInfo(console, &sbi))
                 return;
-
-        GetConsoleScreenBufferInfo(console, &sbi);
         FillConsoleOutputCharacterA(console, ' ',
                 sbi.dwSize.X - sbi.dwCursorPosition.X, sbi.dwCursorPosition,
                 &dummy);
@@ -143,10 +124,8 @@ static void erase_till_end_of_screen(void)
         CONSOLE_SCREEN_BUFFER_INFO sbi;
         DWORD dummy, len;
 
-        if (!console)
+        if(!GetConsoleScreenBufferInfo(console, &sbi))
                 return;
-
-        GetConsoleScreenBufferInfo(console, &sbi);
         len = sbi.dwSize.X - sbi.dwCursorPosition.X +
                         sbi.dwSize.X * (sbi.srWindow.Bottom - sbi.dwCursorPosition.Y);
 
@@ -162,11 +141,9 @@ void reset_screen(void)
         COORD pos;
         DWORD dummy, len;
 
-        if (!console)
-                return;
-
         /* move to start of screen buffer and clear it all */
-        GetConsoleScreenBufferInfo(console, &sbi);
+        if (!GetConsoleScreenBufferInfo(console, &sbi))
+                return;
         pos.X = 0;
         pos.Y = 0;
         SetConsoleCursorPosition(console, pos);
@@ -179,10 +156,8 @@ void move_cursor_row(int n)
 {
         CONSOLE_SCREEN_BUFFER_INFO sbi;
 
-        if (!console)
+        if(!GetConsoleScreenBufferInfo(console, &sbi))
                 return;
-
-        GetConsoleScreenBufferInfo(console, &sbi);
         sbi.dwCursorPosition.Y += n;
         SetConsoleCursorPosition(console, sbi.dwCursorPosition);
 }
@@ -191,10 +166,8 @@ static void move_cursor_column(int n)
 {
         CONSOLE_SCREEN_BUFFER_INFO sbi;
 
-        if (!console)
+        if (!GetConsoleScreenBufferInfo(console, &sbi))
                 return;
-
-        GetConsoleScreenBufferInfo(console, &sbi);
         sbi.dwCursorPosition.X += n;
         SetConsoleCursorPosition(console, sbi.dwCursorPosition);
 }
@@ -204,10 +177,8 @@ static void move_cursor(int x, int y)
         COORD pos;
         CONSOLE_SCREEN_BUFFER_INFO sbi;
 
-        if (!console)
+        if (!GetConsoleScreenBufferInfo(console, &sbi))
                 return;
-
-        GetConsoleScreenBufferInfo(console, &sbi);
         pos.X = sbi.srWindow.Left + x;
         pos.Y = sbi.srWindow.Top + y;
         SetConsoleCursorPosition(console, pos);