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Created attachment 3563 [details]
An untested patch for all platforms.

Comment on attachment 3563 [details]
An untested patch for all platforms.

# HG changeset patch
# User David Lönnhager <dv.lnh.d@gmail.com>
# Date 1547065423 -3600
#      Wed Jan 09 21:23:43 2019 +0100
# Node ID a7379dd9f8cc02c5474517ac49232c05b497d909
# Parent  c70b2574d38d9e040f088032674e5e4870c30853
Add SDL_RWflush().

diff -r c70b2574d38d -r a7379dd9f8cc include/SDL_error.h
--- a/include/SDL_error.h	Wed Jan 09 15:37:21 2019 +0100
+++ b/include/SDL_error.h	Wed Jan 09 21:23:43 2019 +0100
@@ -58,6 +58,7 @@
     SDL_EFREAD,
     SDL_EFWRITE,
     SDL_EFSEEK,
+    SDL_EFFLUSH,
     SDL_UNSUPPORTED,
     SDL_LASTERROR
 } SDL_errorcode;
diff -r c70b2574d38d -r a7379dd9f8cc include/SDL_rwops.h
--- a/include/SDL_rwops.h	Wed Jan 09 15:37:21 2019 +0100
+++ b/include/SDL_rwops.h	Wed Jan 09 21:23:43 2019 +0100
@@ -84,6 +84,14 @@
                               size_t size, size_t num);
 
     /**
+     *  Flushes the buffers for the stream and causes all buffered
+     *  data to be written.
+     *
+     *  \return 0 if successful, or -1 on error.
+     */
+    int (SDLCALL * flush) (struct SDL_RWops * context);
+
+    /**
      *  Close and free an allocated SDL_RWops structure.
      *
      *  \return 0 if successful or -1 on write error when flushing data.
@@ -186,6 +194,7 @@
 #define SDL_RWtell(ctx)         (ctx)->seek(ctx, 0, RW_SEEK_CUR)
 #define SDL_RWread(ctx, ptr, size, n)   (ctx)->read(ctx, ptr, size, n)
 #define SDL_RWwrite(ctx, ptr, size, n)  (ctx)->write(ctx, ptr, size, n)
+#define SDL_RWflush(ctx)  (ctx)->flush(ctx)
 #define SDL_RWclose(ctx)        (ctx)->close(ctx)
 /* @} *//* Read/write macros */
 
diff -r c70b2574d38d -r a7379dd9f8cc src/SDL_error.c
--- a/src/SDL_error.c	Wed Jan 09 15:37:21 2019 +0100
+++ b/src/SDL_error.c	Wed Jan 09 21:23:43 2019 +0100
@@ -166,6 +166,8 @@
         return SDL_SetError("Error writing to datastream");
     case SDL_EFSEEK:
         return SDL_SetError("Error seeking in datastream");
+    case SDL_EFFLUSH:
+        return SDL_SetError("Error flushing datastream");
     case SDL_UNSUPPORTED:
         return SDL_SetError("That operation is not supported");
     default:
diff -r c70b2574d38d -r a7379dd9f8cc src/core/android/SDL_android.c
--- a/src/core/android/SDL_android.c	Wed Jan 09 15:37:21 2019 +0100
+++ b/src/core/android/SDL_android.c	Wed Jan 09 21:23:43 2019 +0100
@@ -1718,6 +1718,12 @@
     return 0;
 }
 
+int Android_JNI_FileFlush(SDL_RWops *ctx)
+{
+    SDL_SetError("Cannot write to Android package filesystem");
+    return 0;
+}
+
 static int Internal_Android_JNI_FileClose(SDL_RWops *ctx, SDL_bool release)
 {
     struct LocalReferenceHolder refs = LocalReferenceHolder_Setup(__FUNCTION__);
diff -r c70b2574d38d -r a7379dd9f8cc src/core/android/SDL_android.h
--- a/src/core/android/SDL_android.h	Wed Jan 09 15:37:21 2019 +0100
+++ b/src/core/android/SDL_android.h	Wed Jan 09 21:23:43 2019 +0100
@@ -67,6 +67,7 @@
 Sint64 Android_JNI_FileSeek(SDL_RWops* ctx, Sint64 offset, int whence);
 size_t Android_JNI_FileRead(SDL_RWops* ctx, void* buffer, size_t size, size_t maxnum);
 size_t Android_JNI_FileWrite(SDL_RWops* ctx, const void* buffer, size_t size, size_t num);
+int Android_JNI_FileFlush(SDL_RWops* ctx);
 int Android_JNI_FileClose(SDL_RWops* ctx);
 
 /* Environment support */
diff -r c70b2574d38d -r a7379dd9f8cc src/file/SDL_rwops.c
--- a/src/file/SDL_rwops.c	Wed Jan 09 15:37:21 2019 +0100
+++ b/src/file/SDL_rwops.c	Wed Jan 09 21:23:43 2019 +0100
@@ -287,6 +287,19 @@
 }
 
 static int SDLCALL
+windows_file_flush(SDL_RWops * context)
+{
+    if (!context || context->hidden.windowsio.h == INVALID_HANDLE_VALUE)
+        return 0;
+
+    if (!FlushFileBuffers(context->hidden.windowsio.h)) {
+        SDL_Error(SDL_EFFLUSH);
+        return -1;
+    }
+    return 0;
+}
+
+static int SDLCALL
 windows_file_close(SDL_RWops * context)
 {
 
@@ -402,6 +415,15 @@
 }
 
 static int SDLCALL
+stdio_flush(SDL_RWops * context)
+{
+    if (fflush(context->hidden.stdio.fp)) {
+        return SDL_Error(SDL_EFFLUSH);
+    }
+    return 0;
+}
+
+static int SDLCALL
 stdio_close(SDL_RWops * context)
 {
     int status = 0;
@@ -496,6 +518,13 @@
 }
 
 static int SDLCALL
+mem_flush(SDL_RWops * context)
+{
+    SDL_SetError("Can't write to read-only memory");
+    return 0;
+}
+
+static int SDLCALL
 mem_close(SDL_RWops * context)
 {
     if (context) {
@@ -555,6 +584,7 @@
     rwops->read = Android_JNI_FileRead;
     rwops->write = Android_JNI_FileWrite;
     rwops->close = Android_JNI_FileClose;
+    rwops->flush = Android_JNI_FileFlush;
     rwops->type = SDL_RWOPS_JNIFILE;
 
 #elif defined(__WIN32__)
@@ -570,6 +600,7 @@
     rwops->read = windows_file_read;
     rwops->write = windows_file_write;
     rwops->close = windows_file_close;
+    rwops->flush = windows_file_flush;
     rwops->type = SDL_RWOPS_WINFILE;
 
 #elif HAVE_STDIO_H
@@ -608,6 +639,7 @@
         rwops->read = stdio_read;
         rwops->write = stdio_write;
         rwops->close = stdio_close;
+        rwops->flush = stdio_flush;
         rwops->hidden.stdio.fp = fp;
         rwops->hidden.stdio.autoclose = autoclose;
         rwops->type = SDL_RWOPS_STDFILE;
@@ -643,6 +675,7 @@
         rwops->read = mem_read;
         rwops->write = mem_write;
         rwops->close = mem_close;
+        rwops->flush = mem_flush;
         rwops->hidden.mem.base = (Uint8 *) mem;
         rwops->hidden.mem.here = rwops->hidden.mem.base;
         rwops->hidden.mem.stop = rwops->hidden.mem.base + size;
@@ -671,6 +704,7 @@
         rwops->read = mem_read;
         rwops->write = mem_writeconst;
         rwops->close = mem_close;
+        rwops->flush = mem_flush;
         rwops->hidden.mem.base = (Uint8 *) mem;
         rwops->hidden.mem.here = rwops->hidden.mem.base;
         rwops->hidden.mem.stop = rwops->hidden.mem.base + size;

Created attachment 3564 [details]
An untested patch for all platforms.

Oops.

We can't add anything to this struct without breaking binary compatibility. Going to leave this assigned to Sam to make a judgement call, but this probably has to be punted to 2.1.

--ryan.

Created attachment 3567 [details]
Untested SDL_RWflush()