[Libguestfs] [PATCH] api: Add a special type for the flags argument.
Richard W.M. Jones
rjones at redhat.com
Tue May 28 12:57:23 UTC 2019
By using a special type we can more naturally express flags in
different programming languages. For example OCaml will prefer an
optional argument containing a list of flags, defaulting to the empty
list:
pread [...] ?(flags = [])
---
generator/generator | 66 +++++++++++++++++++++++++-----------
python/t/400-pread.py | 2 +-
python/t/410-pwrite.py | 2 +-
python/t/460-block-status.py | 4 +--
python/t/500-aio-pread.py | 2 +-
python/t/510-aio-pwrite.py | 2 +-
6 files changed, 53 insertions(+), 25 deletions(-)
diff --git a/generator/generator b/generator/generator
index 9f107dc..5d46938 100755
--- a/generator/generator
+++ b/generator/generator
@@ -820,6 +820,7 @@ and arg =
| BytesPersistIn of string * string (* same as above, but buffer persists *)
| BytesPersistOut of string * string
| Callback of string * arg list (* callback function returning void *)
+| Flags of string (* NBD_CMD_FLAG_* flags *)
| Int of string (* small int *)
| Int64 of string (* 64 bit signed int *)
| Opaque of string (* opaque object, void* in C *)
@@ -1225,7 +1226,7 @@ with the server.";
"pread", {
default_call with
- args = [ BytesOut ("buf", "count"); UInt64 "offset"; UInt32 "flags" ];
+ args = [ BytesOut ("buf", "count"); UInt64 "offset"; Flags "flags" ];
ret = RErr;
shortdesc = "read from the NBD server";
longdesc = "\
@@ -1241,7 +1242,7 @@ protocol extensions).";
"pwrite", {
default_call with
- args = [ BytesIn ("buf", "count"); UInt64 "offset"; UInt32 "flags" ];
+ args = [ BytesIn ("buf", "count"); UInt64 "offset"; Flags "flags" ];
ret = RErr;
shortdesc = "write to the NBD server";
longdesc = "\
@@ -1276,7 +1277,7 @@ C<nbd_aio_disconnect>.";
"flush", {
default_call with
- args = [ UInt32 "flags" ]; ret = RErr;
+ args = [ Flags "flags" ]; ret = RErr;
shortdesc = "flushing pending write requests";
longdesc = "\
Issue the flush command to the NBD server. The function should
@@ -1290,7 +1291,7 @@ protocol extensions).";
"trim", {
default_call with
- args = [ UInt64 "count"; UInt64 "offset"; UInt32 "flags" ];
+ args = [ UInt64 "count"; UInt64 "offset"; Flags "flags" ];
ret = RErr;
shortdesc = "send trim to the NBD server";
longdesc = "\
@@ -1309,7 +1310,7 @@ C<nbd_can_fua>).";
"cache", {
default_call with
- args = [ UInt64 "count"; UInt64 "offset"; UInt32 "flags" ];
+ args = [ UInt64 "count"; UInt64 "offset"; Flags "flags" ];
ret = RErr;
shortdesc = "send cache (prefetch) to the NBD server";
longdesc = "\
@@ -1326,7 +1327,7 @@ protocol extensions).";
"zero", {
default_call with
- args = [ UInt64 "count"; UInt64 "offset"; UInt32 "flags" ];
+ args = [ UInt64 "count"; UInt64 "offset"; Flags "flags" ];
ret = RErr;
shortdesc = "send write zeroes to the NBD server";
longdesc = "\
@@ -1353,7 +1354,7 @@ punching a hole.";
UInt64 "offset";
ArrayAndLen (UInt32 "entries",
"nr_entries")]);
- UInt32 "flags" ];
+ Flags "flags" ];
ret = RErr;
shortdesc = "read the block status of the given range";
longdesc = "\
@@ -1483,7 +1484,7 @@ on the connection.";
"aio_pread", {
default_call with
args = [ BytesPersistOut ("buf", "count"); UInt64 "offset";
- UInt32 "flags" ];
+ Flags "flags" ];
ret = RInt64;
shortdesc = "read from the NBD server";
longdesc = "\
@@ -1497,7 +1498,7 @@ parameters behave as documented in C<nbd_pread>.";
"aio_pwrite", {
default_call with
- args = [ BytesPersistIn ("buf", "count"); UInt64 "offset"; UInt32 "flags" ];
+ args = [ BytesPersistIn ("buf", "count"); UInt64 "offset"; Flags "flags" ];
ret = RInt64;
shortdesc = "write to the NBD server";
longdesc = "\
@@ -1511,7 +1512,7 @@ parameters behave as documented in C<nbd_pwrite>.";
"aio_disconnect", {
default_call with
- args = [ UInt32 "flags" ]; ret = RErr;
+ args = [ Flags "flags" ]; ret = RErr;
shortdesc = "disconnect from the NBD server";
longdesc = "\
Issue the disconnect command to the NBD server. This is
@@ -1526,7 +1527,7 @@ however, C<nbd_shutdown> will call this function if appropriate.";
"aio_flush", {
default_call with
- args = [ UInt32 "flags" ]; ret = RInt64;
+ args = [ Flags "flags" ]; ret = RInt64;
shortdesc = "send flush command to the NBD server";
longdesc = "\
Issue the flush command to the NBD server. This returns the
@@ -1538,7 +1539,7 @@ in C<nbd_flush>.";
"aio_trim", {
default_call with
- args = [ UInt64 "count"; UInt64 "offset"; UInt32 "flags" ];
+ args = [ UInt64 "count"; UInt64 "offset"; Flags "flags" ];
ret = RInt64;
shortdesc = "send trim to the NBD server";
longdesc = "\
@@ -1551,7 +1552,7 @@ in C<nbd_trim>.";
"aio_cache", {
default_call with
- args = [ UInt64 "count"; UInt64 "offset"; UInt32 "flags" ];
+ args = [ UInt64 "count"; UInt64 "offset"; Flags "flags" ];
ret = RInt64;
shortdesc = "send cache (prefetch) to the NBD server";
longdesc = "\
@@ -1564,7 +1565,7 @@ in C<nbd_cache>.";
"aio_zero", {
default_call with
- args = [ UInt64 "count"; UInt64 "offset"; UInt32 "flags" ];
+ args = [ UInt64 "count"; UInt64 "offset"; Flags "flags" ];
ret = RInt64;
shortdesc = "send write zeroes to the NBD server";
longdesc = "\
@@ -1583,7 +1584,7 @@ in C<nbd_zero>.";
UInt64 "offset";
ArrayAndLen (UInt32 "entries",
"nr_entries")]);
- UInt32 "flags" ];
+ Flags "flags" ];
ret = RInt64;
shortdesc = "send block status to the NBD server";
longdesc = "\
@@ -2494,6 +2495,21 @@ let generate_lib_states_c () =
(* Generate C API. *)
+(* Check the API definition. *)
+let () =
+ (* Flags must only appear once in the final argument position. *)
+ List.iter (
+ fun (name, { args }) ->
+ let args = List.rev args in
+ match args with
+ | [] -> ()
+ | Flags _ :: xs
+ | xs ->
+ if List.exists (function Flags _ -> true | _ -> false) xs then
+ failwithf "%s: Flags must appear in final argument position only"
+ name
+ ) handle_calls
+
let generate_lib_libnbd_syms () =
generate_header HashStyle;
@@ -2517,6 +2533,7 @@ let rec name_of_arg = function
| BytesPersistIn (n, len) -> [n; len]
| BytesPersistOut (n, len) -> [n; len]
| Callback (n, _) -> [n]
+| Flags n -> [n]
| Int n -> [n]
| Int64 n -> [n]
| Opaque n -> [n]
@@ -2548,6 +2565,7 @@ let rec print_c_arg_list ?(handle = false) args =
| BytesOut (n, len)
| BytesPersistOut (n, len) -> pr "void *%s, size_t %s" n len
| Callback (n, args) -> pr "void (*%s) " n; print_c_arg_list args
+ | Flags n -> pr "uint32_t %s" n
| Int n -> pr "int %s" n
| Int64 n -> pr "int64_t %s" n
| Opaque n -> pr "void *%s" n
@@ -2950,7 +2968,7 @@ let print_python_binding name { args; ret } =
| UInt64 n -> ()
(* The following not yet implemented for callbacks XXX *)
| ArrayAndLen _ | Bool _ | BytesIn _ | BytesOut _
- | BytesPersistIn _ | BytesPersistOut _ | Callback _
+ | BytesPersistIn _ | BytesPersistOut _ | Callback _ | Flags _
| Int _ | Int64 _ | Path _ | SockAddrAndLen _ | StringList _
| UInt _ | UInt32 _ -> pr " abort ();\n"
) args;
@@ -2965,7 +2983,7 @@ let print_python_binding name { args; ret } =
| UInt64 n -> pr " \"K\""
(* The following not yet implemented for callbacks XXX *)
| ArrayAndLen _ | Bool _ | BytesIn _ | BytesOut _
- | BytesPersistIn _ | BytesPersistOut _ | Callback _
+ | BytesPersistIn _ | BytesPersistOut _ | Callback _ | Flags _
| Int _ | Int64 _ | Path _ | SockAddrAndLen _ | StringList _
| UInt _ | UInt32 _ -> pr " abort ();\n"
) args;
@@ -2978,7 +2996,7 @@ let print_python_binding name { args; ret } =
| UInt64 n -> pr ", %s" n
(* The following not yet implemented for callbacks XXX *)
| ArrayAndLen _ | Bool _ | BytesIn _ | BytesOut _
- | BytesPersistIn _ | BytesPersistOut _ | Callback _
+ | BytesPersistIn _ | BytesPersistOut _ | Callback _ | Flags _
| Int _ | Int64 _ | Path _ | SockAddrAndLen _ | StringList _
| UInt _ | UInt32 _ -> pr " abort ();\n"
) args;
@@ -3009,7 +3027,7 @@ let print_python_binding name { args; ret } =
| Opaque _ -> ()
(* The following not yet implemented for callbacks XXX *)
| ArrayAndLen _ | Bool _ | BytesIn _ | BytesOut _
- | BytesPersistIn _ | BytesPersistOut _ | Callback _
+ | BytesPersistIn _ | BytesPersistOut _ | Callback _ | Flags _
| Int _ | Int64 _ | Path _ | SockAddrAndLen _ | StringList _
| UInt _ | UInt32 _ -> ()
) args;
@@ -3054,6 +3072,9 @@ let print_python_binding name { args; ret } =
pr " struct py_aio_buffer *%s_buf;\n" n
| Callback (n, _) ->
pr " struct %s_%s_data callback_data;\n" name n
+ | Flags n ->
+ pr " uint32_t %s_u32;\n" n;
+ pr " unsigned int %s = 0; /* really uint32_t */\n" n
| Int n -> pr " int %s;\n" n
| Int64 n ->
pr " int64_t %s_i64;\n" n;
@@ -3091,6 +3112,7 @@ let print_python_binding name { args; ret } =
| BytesOut (_, count) -> pr " \"n\""
| BytesPersistOut (_, count) -> pr " \"O\""
| Callback (n, _) -> pr " \"O\""
+ | Flags n -> pr " \"|I\""
| Int n -> pr " \"i\""
| Int64 n -> pr " \"L\""
| Opaque _ -> pr " \"O\""
@@ -3114,6 +3136,7 @@ let print_python_binding name { args; ret } =
| BytesPersistOut (n, _) -> pr ", &%s" n
| BytesOut (_, count) -> pr ", &%s" count
| Callback _ -> pr ", &callback_data.fn"
+ | Flags n -> pr ", &%s" n
| Int n -> pr ", &%s" n
| Int64 n -> pr ", &%s" n
| Opaque n -> pr ", &%s" n
@@ -3162,6 +3185,7 @@ let print_python_binding name { args; ret } =
n;
pr " return NULL;\n";
pr " }\n"
+ | Flags n -> pr " %s_u32 = %s;\n" n n
| Int _ -> ()
| Int64 n -> pr " %s_i64 = %s;\n" n n
| Opaque n ->
@@ -3190,6 +3214,7 @@ let print_python_binding name { args; ret } =
| BytesPersistIn (n, _)
| BytesPersistOut (n, _) -> pr ", %s_buf->data, %s_buf->len" n n
| Callback (n, _) -> pr ", %s_%s_wrapper" name n
+ | Flags n -> pr ", %s_u32" n
| Int n -> pr ", %s" n
| Int64 n -> pr ", %s_i64" n
| Opaque _ -> pr ", &callback_data"
@@ -3223,6 +3248,7 @@ let print_python_binding name { args; ret } =
| BytesIn _
| BytesPersistIn _ | BytesPersistOut _
| Callback _
+ | Flags _
| Int _
| Int64 _
| Opaque _
@@ -3264,6 +3290,7 @@ let print_python_binding name { args; ret } =
| BytesIn (n, _) -> pr " PyBuffer_Release (&%s);\n" n
| BytesPersistIn _ | BytesOut _ | BytesPersistOut _ -> ()
| Callback _ -> ()
+ | Flags _ -> ()
| Int _ -> ()
| Int64 _ -> ()
| Opaque _ -> ()
@@ -3359,6 +3386,7 @@ class NBD (object):
| BytesPersistOut (n, _) -> n
| BytesOut (_, count) -> count
| Callback (n, _) -> n
+ | Flags n -> n ^ "=0"
| Int n -> n
| Int64 n -> n
| Opaque n -> n
diff --git a/python/t/400-pread.py b/python/t/400-pread.py
index da4799b..4d64166 100644
--- a/python/t/400-pread.py
+++ b/python/t/400-pread.py
@@ -20,7 +20,7 @@ import nbd
h = nbd.NBD ()
h.connect_command (["nbdkit", "-s", "--exit-with-parent", "-v",
"pattern", "size=512"])
-buf = h.pread (512, 0, 0)
+buf = h.pread (512, 0)
print ("%r" % buf)
diff --git a/python/t/410-pwrite.py b/python/t/410-pwrite.py
index 9152ba2..811f233 100644
--- a/python/t/410-pwrite.py
+++ b/python/t/410-pwrite.py
@@ -33,7 +33,7 @@ h = nbd.NBD ()
h.connect_command (["nbdkit", "-s", "--exit-with-parent", "-v",
"file", datafile])
h.pwrite (buf1, 0, nbd.CMD_FLAG_FUA)
-buf2 = h.pread (512, 0, 0)
+buf2 = h.pread (512, 0)
assert buf1 == buf2
diff --git a/python/t/460-block-status.py b/python/t/460-block-status.py
index f511091..eeaa7b2 100644
--- a/python/t/460-block-status.py
+++ b/python/t/460-block-status.py
@@ -34,14 +34,14 @@ def f (data, metacontext, offset, e):
return
entries = e
-h.block_status (65536, 0, 42, f, 0)
+h.block_status (65536, 0, 42, f)
assert entries == [ 8192, 0,
8192, 1,
16384, 3,
16384, 2,
16384, 0]
-h.block_status (1024, 32256, 42, f, 0)
+h.block_status (1024, 32256, 42, f)
print ("entries = %r" % entries)
assert entries == [ 512, 3,
16384, 2]
diff --git a/python/t/500-aio-pread.py b/python/t/500-aio-pread.py
index 82199ef..85342f5 100644
--- a/python/t/500-aio-pread.py
+++ b/python/t/500-aio-pread.py
@@ -21,7 +21,7 @@ h = nbd.NBD ()
h.connect_command (["nbdkit", "-s", "--exit-with-parent", "-v",
"pattern", "size=512"])
buf = nbd.aio_buffer (512)
-id = h.aio_pread (buf, 0, 0)
+id = h.aio_pread (buf, 0)
while not (h.aio_command_completed (id)):
h.poll (-1)
diff --git a/python/t/510-aio-pwrite.py b/python/t/510-aio-pwrite.py
index b73464b..4770b83 100644
--- a/python/t/510-aio-pwrite.py
+++ b/python/t/510-aio-pwrite.py
@@ -39,7 +39,7 @@ while not (h.aio_command_completed (id)):
h.poll (-1)
buf2 = nbd.aio_buffer (512)
-id = h.aio_pread (buf2, 0, 0)
+id = h.aio_pread (buf2, 0)
while not (h.aio_command_completed (id)):
h.poll (-1)
--
2.21.0
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