sqlite: add unused file size impl

Change-Id: Ia0985ad51c716ac7a06c479655a60cc641977854

misc/sqlite/sqlite3_os_go.c

@@ -32,6 +32,25 @@ static int go_file_write(sqlite3_file* file, const void* src, int iAmt, sqlite3_
   return 0;
 }
 
+static int go_file_truncate(sqlite3_file* file, sqlite3_int64 size) {
+  // TODO: implement
+  return SQLITE_OK;
+}
+
+static int go_file_sync(sqlite3_file* file, int flags) {
+  // TODO: implement
+  return SQLITE_OK;
+}
+
+static int go_file_file_size(sqlite3_file* file, sqlite3_int64* pSize) {
+  struct GoFileFileSize_return result = GoFileFileSize(((GoFile*) file)->fd);
+  if (result.r0 != 0)
+    return SQLITE_ERROR;
+
+  *pSize = result.r1;
+  return SQLITE_OK;
+}
+
 /* VFS methods */
 
 static int go_vfs_open(sqlite3_vfs* vfs,
@@ -70,6 +89,7 @@ static int go_vfs_full_pathname(sqlite3_vfs* vfs,
                                 const char* zName,
                                 int nOut,
                                 char* zOut) {
+  // TODO: Actually implement this.
   strncpy(zOut, zName, nOut);
   zOut[nOut - 1] = '\0';
   return SQLITE_OK;
@@ -157,10 +177,10 @@ int sqlite3_os_init(void) {
   g_file_methods.xClose = go_file_close;
   g_file_methods.xRead = go_file_read;
   g_file_methods.xWrite = go_file_write;
+  g_file_methods.xTruncate = go_file_truncate;
+  g_file_methods.xSync = go_file_sync;
+  g_file_methods.xFileSize = go_file_file_size;
 #if 0
-  int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
-  int (*xSync)(sqlite3_file*, int flags);
-  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
   int (*xLock)(sqlite3_file*, int);
   int (*xUnlock)(sqlite3_file*, int);
   int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);

misc/sqlite/vfs.go

@@ -35,7 +35,7 @@ func GoFileClose(fd C.int) (int) {
 
 //export GoFileRead
 // Returns 0 on success and -1 on error.
-func GoFileRead(fd C.int, dst *C.char, n C.int, offset C.int) (rv int) {
+func GoFileRead(fd C.int, dst *C.char, n C.int, offset C.long) (rv int) {
 	println("reading", n, "bytes at offset", offset, "from fd", fd);
 	defer func() {
 		println("read returning", rv);
@@ -68,6 +68,27 @@ func GoFileRead(fd C.int, dst *C.char, n C.int, offset C.int) (rv int) {
 	return 0
 }
 
+//export GoFileFileSize
+// rv is 0 on success and -1 on error.
+// TODO: size should be C.long, but cgo fails
+func GoFileFileSize(fd C.int) (rv int, size C.int) {
+	println("getting file size for fd", fd);
+	defer func() {
+		println("returning", rv, "with size", size);
+	}()
+
+	file := GetFile(int(fd))
+	if file == nil {
+		return -1, 0
+	}
+
+	info, err := file.Stat()
+	if err != nil {
+		return -1, 0
+	}
+	return 0, C.int(info.Size)
+}
+
 //export GoVFSOpen
 // fd is -1 on error.
 func GoVFSOpen(filename *C.char, flags C.int) (fd int) {