From: Robert Spalek <robert@ucw.cz>
Date: Fri, 25 Jun 2004 11:53:39 +0000 (+0000)
Subject: added the configuration item BCONFIG_CAN_OVERWRITE, which specifies whether the
X-Git-Tag: holmes-import~1023
X-Git-Url: http://mj.ucw.cz/gitweb/?a=commitdiff_plain;h=6a8ae5549f28ef50110e23ffd418105ef8f38d79;p=libucw.git

added the configuration item BCONFIG_CAN_OVERWRITE, which specifies whether the
caller is allowed to perform the following 0-copy write operation:

1. call bdirect_read_prepare()
2. modify the data directly in the buffer returned (e.g. put \0's there)
3. call bflush() before any seek operation to let the fastbuf know
---

diff --git a/lib/fastbuf.h b/lib/fastbuf.h
index 2ed05341..0104a61f 100644
--- a/lib/fastbuf.h
+++ b/lib/fastbuf.h
@@ -100,6 +100,7 @@ fbbuf_count_written(struct fastbuf *f)
 int bconfig(struct fastbuf *f, uns type, int data);
 
 #define BCONFIG_IS_TEMP_FILE 0
+#define BCONFIG_CAN_OVERWRITE 1
 
 /* Universal functions working on all fastbuf's */
 
diff --git a/lib/fb-file.c b/lib/fb-file.c
index cfc586bb..abb29ddf 100644
--- a/lib/fb-file.c
+++ b/lib/fb-file.c
@@ -89,6 +89,8 @@ bfd_config(struct fastbuf *f, uns item, int value)
     case BCONFIG_IS_TEMP_FILE:
       FB_FILE(f)->is_temp_file = value;
       return 0;
+    case BCONFIG_CAN_OVERWRITE:
+      return 1;
     default:
       return -1;
     }
diff --git a/lib/fb-mmap.c b/lib/fb-mmap.c
index b6f82775..f4f90184 100644
--- a/lib/fb-mmap.c
+++ b/lib/fb-mmap.c
@@ -160,6 +160,8 @@ bfmm_config(struct fastbuf *f, uns item, int value)
     case BCONFIG_IS_TEMP_FILE:
       FB_MMAP(f)->is_temp_file = value;
       return 0;
+    case BCONFIG_CAN_OVERWRITE:
+      return 0;
     default:
       return -1;
     }