[buffer] Mark getter functions as taking const buffer

Fixes https://github.com/harfbuzz/harfbuzz/issues/2873

src/hb-buffer.cc

@@ -841,7 +841,7 @@ hb_buffer_set_content_type (hb_buffer_t              *buffer,
  * Since: 0.9.5
  **/
 hb_buffer_content_type_t
-hb_buffer_get_content_type (hb_buffer_t *buffer)
+hb_buffer_get_content_type (const hb_buffer_t *buffer)
 {
   return buffer->content_type;
 }
@@ -883,7 +883,7 @@ hb_buffer_set_unicode_funcs (hb_buffer_t        *buffer,
  * Since: 0.9.2
  **/
 hb_unicode_funcs_t *
-hb_buffer_get_unicode_funcs (hb_buffer_t        *buffer)
+hb_buffer_get_unicode_funcs (const hb_buffer_t *buffer)
 {
   return buffer->unicode;
 }
@@ -926,7 +926,7 @@ hb_buffer_set_direction (hb_buffer_t    *buffer,
  * Since: 0.9.2
  **/
 hb_direction_t
-hb_buffer_get_direction (hb_buffer_t    *buffer)
+hb_buffer_get_direction (const hb_buffer_t *buffer)
 {
   return buffer->props.direction;
 }
@@ -970,7 +970,7 @@ hb_buffer_set_script (hb_buffer_t *buffer,
  * Since: 0.9.2
  **/
 hb_script_t
-hb_buffer_get_script (hb_buffer_t *buffer)
+hb_buffer_get_script (const hb_buffer_t *buffer)
 {
   return buffer->props.script;
 }
@@ -1014,7 +1014,7 @@ hb_buffer_set_language (hb_buffer_t   *buffer,
  * Since: 0.9.2
  **/
 hb_language_t
-hb_buffer_get_language (hb_buffer_t *buffer)
+hb_buffer_get_language (const hb_buffer_t *buffer)
 {
   return buffer->props.language;
 }
@@ -1050,7 +1050,7 @@ hb_buffer_set_segment_properties (hb_buffer_t *buffer,
  * Since: 0.9.7
  **/
 void
-hb_buffer_get_segment_properties (hb_buffer_t *buffer,
+hb_buffer_get_segment_properties (const hb_buffer_t *buffer,
 				  hb_segment_properties_t *props)
 {
   *props = buffer->props;
@@ -1088,7 +1088,7 @@ hb_buffer_set_flags (hb_buffer_t       *buffer,
  * Since: 0.9.7
  **/
 hb_buffer_flags_t
-hb_buffer_get_flags (hb_buffer_t *buffer)
+hb_buffer_get_flags (const hb_buffer_t *buffer)
 {
   return buffer->flags;
 }
@@ -1127,7 +1127,7 @@ hb_buffer_set_cluster_level (hb_buffer_t               *buffer,
  * Since: 0.9.42
  **/
 hb_buffer_cluster_level_t
-hb_buffer_get_cluster_level (hb_buffer_t *buffer)
+hb_buffer_get_cluster_level (const hb_buffer_t *buffer)
 {
   return buffer->cluster_level;
 }
@@ -1168,7 +1168,7 @@ hb_buffer_set_replacement_codepoint (hb_buffer_t    *buffer,
  * Since: 0.9.31
  **/
 hb_codepoint_t
-hb_buffer_get_replacement_codepoint (hb_buffer_t    *buffer)
+hb_buffer_get_replacement_codepoint (const hb_buffer_t *buffer)
 {
   return buffer->replacement;
 }
@@ -1208,7 +1208,7 @@ hb_buffer_set_invisible_glyph (hb_buffer_t    *buffer,
  * Since: 2.0.0
  **/
 hb_codepoint_t
-hb_buffer_get_invisible_glyph (hb_buffer_t    *buffer)
+hb_buffer_get_invisible_glyph (const hb_buffer_t *buffer)
 {
   return buffer->invisible;
 }
@@ -1248,7 +1248,7 @@ hb_buffer_set_not_found_glyph (hb_buffer_t    *buffer,
  * Since: 3.1.0
  **/
 hb_codepoint_t
-hb_buffer_get_not_found_glyph (hb_buffer_t    *buffer)
+hb_buffer_get_not_found_glyph (const hb_buffer_t *buffer)
 {
   return buffer->not_found;
 }
@@ -1388,7 +1388,7 @@ hb_buffer_set_length (hb_buffer_t  *buffer,
  * Since: 0.9.2
  **/
 unsigned int
-hb_buffer_get_length (hb_buffer_t *buffer)
+hb_buffer_get_length (const hb_buffer_t *buffer)
 {
   return buffer->len;
 }

src/hb-buffer.h

@@ -289,7 +289,7 @@ hb_buffer_set_content_type (hb_buffer_t              *buffer,
 			    hb_buffer_content_type_t  content_type);
 
 HB_EXTERN hb_buffer_content_type_t
-hb_buffer_get_content_type (hb_buffer_t *buffer);
+hb_buffer_get_content_type (const hb_buffer_t *buffer);
 
 
 HB_EXTERN void
@@ -297,21 +297,21 @@ hb_buffer_set_unicode_funcs (hb_buffer_t        *buffer,
 			     hb_unicode_funcs_t *unicode_funcs);
 
 HB_EXTERN hb_unicode_funcs_t *
-hb_buffer_get_unicode_funcs (hb_buffer_t        *buffer);
+hb_buffer_get_unicode_funcs (const hb_buffer_t  *buffer);
 
 HB_EXTERN void
 hb_buffer_set_direction (hb_buffer_t    *buffer,
 			 hb_direction_t  direction);
 
 HB_EXTERN hb_direction_t
-hb_buffer_get_direction (hb_buffer_t *buffer);
+hb_buffer_get_direction (const hb_buffer_t *buffer);
 
 HB_EXTERN void
 hb_buffer_set_script (hb_buffer_t *buffer,
 		      hb_script_t  script);
 
 HB_EXTERN hb_script_t
-hb_buffer_get_script (hb_buffer_t *buffer);
+hb_buffer_get_script (const hb_buffer_t *buffer);
 
 HB_EXTERN void
 hb_buffer_set_language (hb_buffer_t   *buffer,
@@ -319,14 +319,14 @@ hb_buffer_set_language (hb_buffer_t   *buffer,
 
 
 HB_EXTERN hb_language_t
-hb_buffer_get_language (hb_buffer_t *buffer);
+hb_buffer_get_language (const hb_buffer_t *buffer);
 
 HB_EXTERN void
 hb_buffer_set_segment_properties (hb_buffer_t *buffer,
 				  const hb_segment_properties_t *props);
 
 HB_EXTERN void
-hb_buffer_get_segment_properties (hb_buffer_t *buffer,
+hb_buffer_get_segment_properties (const hb_buffer_t *buffer,
 				  hb_segment_properties_t *props);
 
 HB_EXTERN void
@@ -397,7 +397,7 @@ hb_buffer_set_flags (hb_buffer_t       *buffer,
 		     hb_buffer_flags_t  flags);
 
 HB_EXTERN hb_buffer_flags_t
-hb_buffer_get_flags (hb_buffer_t *buffer);
+hb_buffer_get_flags (const hb_buffer_t *buffer);
 
 /**
  * hb_buffer_cluster_level_t:
@@ -439,7 +439,7 @@ hb_buffer_set_cluster_level (hb_buffer_t               *buffer,
 			     hb_buffer_cluster_level_t  cluster_level);
 
 HB_EXTERN hb_buffer_cluster_level_t
-hb_buffer_get_cluster_level (hb_buffer_t *buffer);
+hb_buffer_get_cluster_level (const hb_buffer_t *buffer);
 
 /**
  * HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT:
@@ -456,21 +456,21 @@ hb_buffer_set_replacement_codepoint (hb_buffer_t    *buffer,
 				     hb_codepoint_t  replacement);
 
 HB_EXTERN hb_codepoint_t
-hb_buffer_get_replacement_codepoint (hb_buffer_t    *buffer);
+hb_buffer_get_replacement_codepoint (const hb_buffer_t *buffer);
 
 HB_EXTERN void
 hb_buffer_set_invisible_glyph (hb_buffer_t    *buffer,
 			       hb_codepoint_t  invisible);
 
 HB_EXTERN hb_codepoint_t
-hb_buffer_get_invisible_glyph (hb_buffer_t    *buffer);
+hb_buffer_get_invisible_glyph (const hb_buffer_t *buffer);
 
 HB_EXTERN void
 hb_buffer_set_not_found_glyph (hb_buffer_t    *buffer,
 			       hb_codepoint_t  not_found);
 
 HB_EXTERN hb_codepoint_t
-hb_buffer_get_not_found_glyph (hb_buffer_t    *buffer);
+hb_buffer_get_not_found_glyph (const hb_buffer_t *buffer);
 
 
 /*
@@ -552,7 +552,7 @@ hb_buffer_set_length (hb_buffer_t  *buffer,
 		      unsigned int  length);
 
 HB_EXTERN unsigned int
-hb_buffer_get_length (hb_buffer_t *buffer);
+hb_buffer_get_length (const hb_buffer_t *buffer);
 
 /* Getting glyphs out of the buffer */