[adb] Add a getter for native Win32 file handle

+ adb_pread() and adb_pwrite() functions for simpler cross
  platform file operations

Test: builds
Change-Id: I7e2b23e1da79acd7be974a3d7e1be0fb77d7d2c6
diff --git a/adb/sysdeps.h b/adb/sysdeps.h
index b0e7fa0..b08a13b 100644
--- a/adb/sysdeps.h
+++ b/adb/sysdeps.h
@@ -91,11 +91,14 @@
 extern int adb_open(const char* path, int options);
 extern int adb_creat(const char* path, int mode);
 extern int adb_read(borrowed_fd fd, void* buf, int len);
+extern int adb_pread(borrowed_fd fd, void* buf, int len, off64_t offset);
 extern int adb_write(borrowed_fd fd, const void* buf, int len);
+extern int adb_pwrite(borrowed_fd fd, const void* buf, int len, off64_t offset);
 extern int64_t adb_lseek(borrowed_fd fd, int64_t pos, int where);
 extern int adb_shutdown(borrowed_fd fd, int direction = SHUT_RDWR);
 extern int adb_close(int fd);
 extern int adb_register_socket(SOCKET s);
+extern HANDLE adb_get_os_handle(borrowed_fd fd);
 
 // See the comments for the !defined(_WIN32) version of unix_close().
 static __inline__ int unix_close(int fd) {
@@ -115,6 +118,9 @@
 #undef   read
 #define  read  ___xxx_read
 
+#undef pread
+#define pread ___xxx_pread
+
 // See the comments for the !defined(_WIN32) version of unix_write().
 static __inline__ int unix_write(borrowed_fd fd, const void* buf, size_t len) {
     return write(fd.get(), buf, len);
@@ -122,6 +128,9 @@
 #undef   write
 #define  write  ___xxx_write
 
+#undef pwrite
+#define pwrite ___xxx_pwrite
+
 // See the comments for the !defined(_WIN32) version of unix_lseek().
 static __inline__ int unix_lseek(borrowed_fd fd, int pos, int where) {
     return lseek(fd.get(), pos, where);
@@ -415,6 +424,14 @@
     return TEMP_FAILURE_RETRY(read(fd.get(), buf, len));
 }
 
+static __inline__ int adb_pread(int fd, void* buf, size_t len, off64_t offset) {
+#if defined(__APPLE__)
+    return TEMP_FAILURE_RETRY(pread(fd, buf, len, offset));
+#else
+    return TEMP_FAILURE_RETRY(pread64(fd, buf, len, offset));
+#endif
+}
+
 // Like unix_read(), but does not handle EINTR.
 static __inline__ int unix_read_interruptible(borrowed_fd fd, void* buf, size_t len) {
     return read(fd.get(), buf, len);
@@ -422,12 +439,25 @@
 
 #undef read
 #define read ___xxx_read
+#undef pread
+#define pread ___xxx_pread
 
 static __inline__ int adb_write(borrowed_fd fd, const void* buf, size_t len) {
     return TEMP_FAILURE_RETRY(write(fd.get(), buf, len));
 }
+
+static __inline__ int adb_pwrite(int fd, const void* buf, size_t len, off64_t offset) {
+#if defined(__APPLE__)
+    return TEMP_FAILURE_RETRY(pwrite(fd, buf, len, offset));
+#else
+    return TEMP_FAILURE_RETRY(pwrite64(fd, buf, len, offset));
+#endif
+}
+
 #undef   write
 #define  write  ___xxx_write
+#undef pwrite
+#define pwrite ___xxx_pwrite
 
 static __inline__ int64_t adb_lseek(borrowed_fd fd, int64_t pos, int where) {
 #if defined(__APPLE__)