From 0b8a4f9cb94f2929ba162726abde48fcfe1c5ea3 Mon Sep 17 00:00:00 2001
From: Seunghun Lee <shiin.lee@samsung.com>
Date: Tue, 13 Jun 2023 08:57:20 +0900
Subject: [PATCH] Use -fmacro-prefix-map to strip build path

This is taken from wlroots to strip the build-path dependent bytes
of each __FILE__ string used by ds_log and related functions.

Change-Id: I5660355f210615024bd4018cf63b6da216a128e8
---
 include/libds/log.h | 10 ++++++++--
 meson.build         | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/include/libds/log.h b/include/libds/log.h
index e588968..7399a0a 100644
--- a/include/libds/log.h
+++ b/include/libds/log.h
@@ -31,15 +31,21 @@ enum ds_log_level ds_log_get_level(void);
 #define _DS_ATTRIB_PRINTF(start, end)
 #endif
 
+#ifdef _DS_REL_SRC_DIR
+#define _DS_FILENAME ((const char *)__FILE__ + sizeof(_DS_REL_SRC_DIR) - 1)
+#else
+#define _DS_FILENAME __FILE__
+#endif
+
 void _ds_log(enum ds_log_level level, const char *format, ...) _DS_ATTRIB_PRINTF(2, 3);
 void _ds_vlog(enum ds_log_level level, const char *format, va_list args) _DS_ATTRIB_PRINTF(2, 0);
 void ds_log_errno(enum ds_log_level level, const char *fmt, ...);
 
 #define ds_log(level, fmt, ...) \
-    _ds_log(level, "[%s:%d] " fmt, __FILE__, __LINE__, ##__VA_ARGS__)
+    _ds_log(level, "[%s:%d] " fmt, _DS_FILENAME, __LINE__, ##__VA_ARGS__)
 
 #define ds_vlog(level, fmt, args) \
-    _ds_vlog(level, "[%s:%d] " fmt, __FILE__, __LINE__, args)
+    _ds_vlog(level, "[%s:%d] " fmt, _DS_FILENAME, __LINE__, args)
 
 #define ds_err(fmt, ...) \
     ds_log(DS_ERR, fmt, ##__VA_ARGS__)
diff --git a/meson.build b/meson.build
index a6f2d55..a9c9fd7 100644
--- a/meson.build
+++ b/meson.build
@@ -26,6 +26,42 @@ foreach a : global_args_maybe
 endforeach
 add_global_arguments(global_args, language: 'c')
 
+# Compute the relative path used by compiler invocations.
+source_root = meson.current_source_dir().split('/')
+build_root = meson.global_build_root().split('/')
+relative_dir_parts = []
+i = 0
+in_prefix = true
+foreach p: build_root
+  if i >= source_root.length() or not in_prefix or p != source_root[i]
+    in_prefix = false
+    relative_dir_parts += '..'
+  endif
+  i += 1
+endforeach
+i = 0
+in_prefix = true
+foreach p : source_root
+  if i >= build_root.length() or not in_prefix or build_root[i] != p
+    in_prefix = false
+    relative_dir_parts += p
+  endif
+  i += 1
+endforeach
+relative_dir = join_paths(relative_dir_parts) + '/'
+
+if cc.has_argument('-fmacro-prefix-map=/prefix/to/hide=')
+  add_project_arguments(
+    '-fmacro-prefix-map=@0@='.format(relative_dir),
+    language: 'c',
+  )
+else
+  add_project_arguments(
+    '-D_DS_REL_SRC_DIR="@0@"'.format(relative_dir),
+    language: 'c',
+  )
+endif
+
 libds_version = meson.project_version()
 version_arr = libds_version.split('.')
 libds_version_major = version_arr[0]
-- 
2.7.4