[gtksourceview] fileloader: use allocated chunk buffer

[Christian Hergert <chergert src gnome org>]

commit 5b84d6ef0c6858060814d20d5bb01235e7c90f6a
Author: Christian Hergert <chergert redhat com>
Date:   Tue Dec 14 14:51:33 2021 -0800

    fileloader: use allocated chunk buffer
    
    Previously, this had the chunk_buffer inline in the TaskData struct.
    Unfortunately, since that creates an allocation that is offset from the
    head of the struct, the value of having data inline is vastly overwhelmed
    by all of the coordinating layers doing additional memory copies.
    
    Buffers for data reads from storage should always be page aligned,
    especially if you're reading multiples of the page size.

 gtksourceview/gtksourcefileloader.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)
---
diff --git a/gtksourceview/gtksourcefileloader.c b/gtksourceview/gtksourcefileloader.c
index fcee5a47..1e905783 100644
--- a/gtksourceview/gtksourcefileloader.c
+++ b/gtksourceview/gtksourcefileloader.c
@@ -32,6 +32,7 @@
 #include "gtksourceencoding-private.h"
 #include "gtksource-enumtypes.h"
 #include "gtksourcetrace.h"
+#include "gtksourceutils-private.h"
 
 /**
  * GtkSourceFileLoader:
@@ -65,7 +66,8 @@ enum
        PROP_INPUT_STREAM
 };
 
-#define READ_CHUNK_SIZE 8192
+#define READ_N_PAGES 2
+#define READ_CHUNK_SIZE (_gtk_source_utils_get_page_size()*READ_N_PAGES)
 #define LOADER_QUERY_ATTRIBUTES G_FILE_ATTRIBUTE_STANDARD_CONTENT_TYPE "," \
                                G_FILE_ATTRIBUTE_STANDARD_TYPE "," \
                                G_FILE_ATTRIBUTE_TIME_MODIFIED "," \
@@ -126,7 +128,7 @@ typedef struct
        goffset total_size;
 
        gssize chunk_bytes_read;
-       gchar chunk_buffer[READ_CHUNK_SIZE];
+       gchar *chunk_buffer;
 
        guint guess_content_type_from_content : 1;
        guint tried_mount : 1;
@@ -140,7 +142,14 @@ static void read_file_chunk (GTask *task);
 static TaskData *
 task_data_new (void)
 {
-       return g_new0 (TaskData, 1);
+       TaskData *task_data = g_new0 (TaskData, 1);
+
+       task_data->chunk_buffer =
+               _gtk_source_utils_aligned_alloc (_gtk_source_utils_get_page_size (),
+                                                READ_N_PAGES,
+                                                _gtk_source_utils_get_page_size ());
+
+       return task_data;
 }
 
 static void
@@ -162,6 +171,8 @@ task_data_free (gpointer data)
                task_data->progress_cb_notify (task_data->progress_cb_data);
        }
 
+       _gtk_source_utils_aligned_free (task_data->chunk_buffer);
+
        g_free (task_data);
 }