compress: compression disabled by default

We now allow libssh2_session_flag() to enable compression with a new
flag and I added documentation for the previous LIBSSH2_FLAG_SIGPIPE
flag which I wasn't really aware of!

docs/libssh2_session_flag.3

@@ -5,11 +5,21 @@
 libssh2_session_flag - TODO
 .SH SYNOPSIS
 int
-libssh2_session_flag(LIBSSH2_SESSION * session, int flag, int value);
+libssh2_session_flag(LIBSSH2_SESSION *session, int flag, int value);
 .SH DESCRIPTION
-This function has no purpose and no documented flags can be set nor read.
+Set options for the created session. \fIflag\fP is the option to set, while
+\fIvalue\fP is typically set to 1 or 0 to enable or disable the option.
+.SH FLAGS
+.IP LIBSSH2_FLAG_SIGPIPE
+If set, libssh2 will not attempt to block SIGPIPEs but will let them trigger
+from the underlying socket layer.
+.IP LIBSSH2_FLAG_COMPRESS
+If set - before the connection negotiation is performed - libssh2 will try to
+negotiate compression enabling for this connection. By default libssh2 will
+not attempt to use compression.
 .SH RETURN VALUE
-0
-.SH ERRORS
-Its mere existence is an error
+Returns regular libssh2 error code.
+.SH AVAILABILITY
+This function has existed since the age of dawn. LIBSSH2_FLAG_COMPRESS was
+added in version 1.2.8.
 .SH SEE ALSO

include/libssh2.h

@@ -1,5 +1,5 @@
 /* Copyright (c) 2004-2009, Sara Golemon <sarag@libssh2.org>
- * Copyright (c) 2009 by Daniel Stenberg
+ * Copyright (c) 2009-2010 Daniel Stenberg
  * Copyright (c) 2010 Simon Josefsson <simon@josefsson.org>
  * All rights reserved.
  *
@@ -253,8 +253,9 @@ typedef struct _LIBSSH2_USERAUTH_KBDINT_RESPONSE
 #define LIBSSH2_METHOD_LANG_CS      8
 #define LIBSSH2_METHOD_LANG_SC      9
 
-/* session.flags bits */
-#define LIBSSH2_FLAG_SIGPIPE        0x00000001
+/* flags */
+#define LIBSSH2_FLAG_SIGPIPE        1
+#define LIBSSH2_FLAG_COMPRESS       2
 
 typedef struct _LIBSSH2_SESSION                     LIBSSH2_SESSION;
 typedef struct _LIBSSH2_CHANNEL                     LIBSSH2_CHANNEL;

src/libssh2_priv.h

@@ -661,6 +661,11 @@ struct _LIBSSH2_SFTP
 
 #define LIBSSH2_SCP_RESPONSE_BUFLEN     256
 
+struct flags {
+    int sigpipe;  /* LIBSSH2_FLAG_SIGPIPE */
+    int compress; /* LIBSSH2_FLAG_COMPRESS */
+};
+
 struct _LIBSSH2_SESSION
 {
     /* Memory management callbacks */
@@ -681,7 +686,9 @@ struct _LIBSSH2_SESSION
     char *hostkey_prefs;
 
     int state;
-    int flags;
+
+    /* Flag options */
+    struct flags flag;
 
     /* Agreed Key Exchange Method */
     const LIBSSH2_KEX_METHOD *kex;
@@ -930,8 +937,8 @@ struct _LIBSSH2_SESSION
 
 /* session.flag helpers */
 #ifdef MSG_NOSIGNAL
-#define LIBSSH2_SOCKET_SEND_FLAGS(session)      (((session)->flags & LIBSSH2_FLAG_SIGPIPE) ? 0 : MSG_NOSIGNAL)
-#define LIBSSH2_SOCKET_RECV_FLAGS(session)      (((session)->flags & LIBSSH2_FLAG_SIGPIPE) ? 0 : MSG_NOSIGNAL)
+#define LIBSSH2_SOCKET_SEND_FLAGS(session)      (((session)->flag.sigpipe) ? 0 : MSG_NOSIGNAL)
+#define LIBSSH2_SOCKET_RECV_FLAGS(session)      (((session)->flag.sigpipe) ? 0 : MSG_NOSIGNAL)
 #else
 /* If MSG_NOSIGNAL isn't defined we're SOL on blocking SIGPIPE */
 #define LIBSSH2_SOCKET_SEND_FLAGS(session)      0

src/session.c

@@ -1227,19 +1227,24 @@ libssh2_session_last_errno(LIBSSH2_SESSION * session)
  *
  * Set/Get session flags
  *
- * Passing flag==0 will avoid changing session->flags while still returning
- * its current value
+ * Return error code.
  */
 LIBSSH2_API int
 libssh2_session_flag(LIBSSH2_SESSION * session, int flag, int value)
 {
-    if (value) {
-        session->flags |= flag;
-    } else {
-        session->flags &= ~flag;
+    switch(flag) {
+    case LIBSSH2_FLAG_SIGPIPE:
+        session->flag.sigpipe = value;
+        break;
+    case LIBSSH2_FLAG_COMPRESS:
+        session->flag.compress = value;
+        break;
+    default:
+        /* unknown flag */
+        return LIBSSH2_ERROR_INVAL;
     }
 
-    return session->flags;
+    return LIBSSH2_ERROR_NONE;
 }
 
 /* _libssh2_session_set_blocking