[Qemu-devel] [PATCH v4 0/8] don't use Yoda conditions

[Qemu-devel] [PATCH v4 0/8] don't use Yoda conditions

[arei.gonglei]

From: Gonglei <arei.gonglei@huawei.com>

$WHATEVER: don't use 'Yoda conditions'

'Yoda conditions' are not part of idiomatic QEMU coding
style, so rewrite them in the more usual order.

v4:
 - trivial typo for patch 1/8 suggested by Eric, thanks.

v3:
 - rewrite CODINT_STYLE file suggested by Eric, thanks.
 - rename the patch serials.
 - imitate nearby code about using '!value' or 'value == NULL' at
   every patch suggested by Markus.

v2:
 - add more specific commit messages suggested by PMM, thanks.
 - introduce section of conditional statement to CODING_STYLE.

Gonglei (8):
  CODING_STYLE: Section about conditional statement
  usb: don't use 'Yoda conditions'
  audio: don't use 'Yoda conditions'
  isa-bus: don't use 'Yoda conditions'
  don't use 'Yoda conditions'
  spice: don't use 'Yoda conditions'
  vl: don't use 'Yoda conditions'
  vmxnet3: don't use 'Yoda conditions'

 CODING_STYLE         | 14 ++++++++++++++
 hw/audio/gus.c       |  2 +-
 hw/audio/hda-codec.c |  3 ++-
 hw/audio/sb16.c      |  6 +++---
 hw/isa/isa-bus.c     |  2 +-
 hw/net/vmxnet3.c     | 16 ++++++++--------
 hw/usb/dev-audio.c   |  2 +-
 hw/usb/dev-mtp.c     |  4 ++--
 hw/usb/hcd-ehci.c    |  2 +-
 qdev-monitor.c       |  2 +-
 qemu-char.c          |  2 +-
 ui/spice-core.c      |  4 ++--
 util/qemu-sockets.c  |  2 +-
 vl.c                 |  5 +++--
 14 files changed, 41 insertions(+), 25 deletions(-)

-- 
1.7.12.4

[Qemu-devel] [PATCH v4 1/8] CODING_STYLE: Section about conditional statement

[arei.gonglei]

From: Gonglei <arei.gonglei@huawei.com>

Yoda conditions lack readability, and QEMU has a
strict compiler configuration for checking a common
mistake like "if (dev = NULL)". Make it a written rule.

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 CODING_STYLE | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/CODING_STYLE b/CODING_STYLE
index 4280945..d46cfa5 100644
--- a/CODING_STYLE
+++ b/CODING_STYLE
@@ -91,3 +91,17 @@ Mixed declarations (interleaving statements and declarations within blocks)
 are not allowed; declarations should be at the beginning of blocks.  In other
 words, the code should not generate warnings if using GCC's
 -Wdeclaration-after-statement option.
+
+6. Conditional statements
+
+When comparing a variable for (in)equality with a constant, list the
+constant on the right, as in:
+
+if (a == 1) {
+    /* Reads like: "If a equals 1" */
+    do_something();
+}
+
+Rationale: Yoda conditions (as in 'if (1 == a)') are awkward to read.
+Besides, good compilers already warn users when '==' is mis-typed as '=',
+even when the constant is on the right.
-- 
1.7.12.4

[Qemu-devel] [PATCH v4 2/8] usb: don't use 'Yoda conditions'

[arei.gonglei]

From: Gonglei <arei.gonglei@huawei.com>

imitate nearby code about using '!value' or 'value == NULL'

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
---
 hw/usb/dev-audio.c | 2 +-
 hw/usb/dev-mtp.c   | 4 ++--
 hw/usb/hcd-ehci.c  | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/usb/dev-audio.c b/hw/usb/dev-audio.c
index bfebfe9..7b9957b 100644
--- a/hw/usb/dev-audio.c
+++ b/hw/usb/dev-audio.c
@@ -371,7 +371,7 @@ static void output_callback(void *opaque, int avail)
             return;
         }
         data = streambuf_get(&s->out.buf);
-        if (NULL == data) {
+        if (!data) {
             return;
         }
         AUD_write(s->out.voice, data, USBAUDIO_PACKET_SIZE);
diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c
index 384d4a5..0820046 100644
--- a/hw/usb/dev-mtp.c
+++ b/hw/usb/dev-mtp.c
@@ -832,7 +832,7 @@ static void usb_mtp_command(MTPState *s, MTPControl *c)
             return;
         }
         data_in = usb_mtp_get_object(s, c, o);
-        if (NULL == data_in) {
+        if (data_in == NULL) {
             usb_mtp_queue_result(s, RES_GENERAL_ERROR,
                                  c->trans, 0, 0, 0);
             return;
@@ -851,7 +851,7 @@ static void usb_mtp_command(MTPState *s, MTPControl *c)
             return;
         }
         data_in = usb_mtp_get_partial_object(s, c, o);
-        if (NULL == data_in) {
+        if (data_in == NULL) {
             usb_mtp_queue_result(s, RES_GENERAL_ERROR,
                                  c->trans, 0, 0, 0);
             return;
diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index a00a93c..448e007 100644
--- a/hw/usb/hcd-ehci.c
+++ b/hw/usb/hcd-ehci.c
@@ -1596,7 +1596,7 @@ static EHCIQueue *ehci_state_fetchqh(EHCIState *ehci, int async)
 
     entry = ehci_get_fetch_addr(ehci, async);
     q = ehci_find_queue_by_qh(ehci, entry, async);
-    if (NULL == q) {
+    if (q == NULL) {
         q = ehci_alloc_queue(ehci, entry, async);
     }
 
-- 
1.7.12.4

[Qemu-devel] [PATCH v4 3/8] audio: don't use 'Yoda conditions'

[arei.gonglei]

From: Gonglei <arei.gonglei@huawei.com>

imitate nearby code about using '!value' or 'value == NULL'

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
---
 hw/audio/gus.c       | 2 +-
 hw/audio/hda-codec.c | 3 ++-
 hw/audio/sb16.c      | 6 +++---
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/hw/audio/gus.c b/hw/audio/gus.c
index bba6840..4a43ce7 100644
--- a/hw/audio/gus.c
+++ b/hw/audio/gus.c
@@ -212,7 +212,7 @@ static int GUS_read_DMA (void *opaque, int nchan, int dma_pos, int dma_len)
         pos += copied;
     }
 
-    if (0 == ((mode >> 4) & 1)) {
+    if (((mode >> 4) & 1) == 0) {
         DMA_release_DREQ (s->emu.gusdma);
     }
     return dma_len;
diff --git a/hw/audio/hda-codec.c b/hw/audio/hda-codec.c
index cbcf521..3c03ff5 100644
--- a/hw/audio/hda-codec.c
+++ b/hw/audio/hda-codec.c
@@ -489,8 +489,9 @@ static int hda_audio_init(HDACodecDevice *hda, const struct desc_codec *desc)
     for (i = 0; i < a->desc->nnodes; i++) {
         node = a->desc->nodes + i;
         param = hda_codec_find_param(node, AC_PAR_AUDIO_WIDGET_CAP);
-        if (NULL == param)
+        if (param == NULL) {
             continue;
+        }
         type = (param->val & AC_WCAP_TYPE) >> AC_WCAP_TYPE_SHIFT;
         switch (type) {
         case AC_WID_AUD_OUT:
diff --git a/hw/audio/sb16.c b/hw/audio/sb16.c
index 60c4b3b..bda26d0 100644
--- a/hw/audio/sb16.c
+++ b/hw/audio/sb16.c
@@ -928,7 +928,7 @@ static IO_WRITE_PROTO (dsp_write)
 /*         if (s->highspeed) */
 /*             break; */
 
-        if (0 == s->needed_bytes) {
+        if (s->needed_bytes == 0) {
             command (s, val);
 #if 0
             if (0 == s->needed_bytes) {
@@ -1212,7 +1212,7 @@ static int SB_read_DMA (void *opaque, int nchan, int dma_pos, int dma_len)
 #endif
 
     if (till <= copy) {
-        if (0 == s->dma_auto) {
+        if (s->dma_auto == 0) {
             copy = till;
         }
     }
@@ -1224,7 +1224,7 @@ static int SB_read_DMA (void *opaque, int nchan, int dma_pos, int dma_len)
     if (s->left_till_irq <= 0) {
         s->mixer_regs[0x82] |= (nchan & 4) ? 2 : 1;
         qemu_irq_raise (s->pic);
-        if (0 == s->dma_auto) {
+        if (s->dma_auto == 0) {
             control (s, 0);
             speaker (s, 0);
         }
-- 
1.7.12.4

[Qemu-devel] [PATCH v4 4/8] isa-bus: don't use 'Yoda conditions'

[arei.gonglei]

From: Gonglei <arei.gonglei@huawei.com>

imitate nearby code about using '!value' or 'value == NULL'

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
---
 hw/isa/isa-bus.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/isa/isa-bus.c b/hw/isa/isa-bus.c
index b28981b..cc85e53 100644
--- a/hw/isa/isa-bus.c
+++ b/hw/isa/isa-bus.c
@@ -50,7 +50,7 @@ ISABus *isa_bus_new(DeviceState *dev, MemoryRegion *address_space_io)
         fprintf(stderr, "Can't create a second ISA bus\n");
         return NULL;
     }
-    if (NULL == dev) {
+    if (!dev) {
         dev = qdev_create(NULL, "isabus-bridge");
         qdev_init_nofail(dev);
     }
-- 
1.7.12.4

[Qemu-devel] [PATCH v4 5/8] don't use 'Yoda conditions'

[arei.gonglei]

From: Gonglei <arei.gonglei@huawei.com>

imitate nearby code about using '!value' or 'value == NULL'

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
---
 qdev-monitor.c      | 2 +-
 qemu-char.c         | 2 +-
 util/qemu-sockets.c | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/qdev-monitor.c b/qdev-monitor.c
index f87f3d8..81a4e9b 100644
--- a/qdev-monitor.c
+++ b/qdev-monitor.c
@@ -694,7 +694,7 @@ void qmp_device_del(const char *id, Error **errp)
     DeviceState *dev;
 
     dev = qdev_find_recursive(sysbus_get_default(), id);
-    if (NULL == dev) {
+    if (!dev) {
         error_set(errp, QERR_DEVICE_NOT_FOUND, id);
         return;
     }
diff --git a/qemu-char.c b/qemu-char.c
index 956be49..70d5a64 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -4117,7 +4117,7 @@ void qmp_chardev_remove(const char *id, Error **errp)
     CharDriverState *chr;
 
     chr = qemu_chr_find(id);
-    if (NULL == chr) {
+    if (chr == NULL) {
         error_setg(errp, "Chardev '%s' not found", id);
         return;
     }
diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
index 74cf078..5d38395 100644
--- a/util/qemu-sockets.c
+++ b/util/qemu-sockets.c
@@ -732,7 +732,7 @@ int unix_connect_opts(QemuOpts *opts, Error **errp,
     ConnectState *connect_state = NULL;
     int sock, rc;
 
-    if (NULL == path) {
+    if (path == NULL) {
         error_setg(errp, "unix connect: no path specified");
         return -1;
     }
-- 
1.7.12.4

[Qemu-devel] [PATCH v4 6/8] spice: don't use 'Yoda conditions'

[arei.gonglei]

From: Gonglei <arei.gonglei@huawei.com>

imitate nearby code about using '!value' or 'value == NULL'

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
---
 ui/spice-core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/ui/spice-core.c b/ui/spice-core.c
index 7bb91e6..1a2fb4b 100644
--- a/ui/spice-core.c
+++ b/ui/spice-core.c
@@ -677,7 +677,7 @@ void qemu_spice_init(void)
 
     if (tls_port) {
         x509_dir = qemu_opt_get(opts, "x509-dir");
-        if (NULL == x509_dir) {
+        if (!x509_dir) {
             x509_dir = ".";
         }
 
@@ -803,7 +803,7 @@ void qemu_spice_init(void)
 
     seamless_migration = qemu_opt_get_bool(opts, "seamless-migration", 0);
     spice_server_set_seamless_migration(spice_server, seamless_migration);
-    if (0 != spice_server_init(spice_server, &core_interface)) {
+    if (spice_server_init(spice_server, &core_interface) != 0) {
         error_report("failed to initialize spice server");
         exit(1);
     };
-- 
1.7.12.4

[Qemu-devel] [PATCH v4 7/8] vl: don't use 'Yoda conditions'

[arei.gonglei]

From: Gonglei <arei.gonglei@huawei.com>

imitate nearby code about using '!value' or 'value == NULL'

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
---
 vl.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/vl.c b/vl.c
index fe451aa..04c5abd 100644
--- a/vl.c
+++ b/vl.c
@@ -1136,7 +1136,7 @@ static int drive_init_func(QemuOpts *opts, void *opaque)
 
 static int drive_enable_snapshot(QemuOpts *opts, void *opaque)
 {
-    if (NULL == qemu_opt_get(opts, "snapshot")) {
+    if (qemu_opt_get(opts, "snapshot") == NULL) {
         qemu_opt_set(opts, "snapshot", "on");
     }
     return 0;
@@ -2488,8 +2488,9 @@ static int foreach_device_config(int type, int (*func)(const char *cmdline))
         loc_push_restore(&conf->loc);
         rc = func(conf->cmdline);
         loc_pop(&conf->loc);
-        if (0 != rc)
+        if (rc) {
             return rc;
+        }
     }
     return 0;
 }
-- 
1.7.12.4

[Qemu-devel] [PATCH v4 8/8] vmxnet3: don't use 'Yoda conditions'

[arei.gonglei]

From: Gonglei <arei.gonglei@huawei.com>

imitate nearby code about using '!value' or 'value == NULL'

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
---
 hw/net/vmxnet3.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c
index 77bea6f..588149d 100644
--- a/hw/net/vmxnet3.c
+++ b/hw/net/vmxnet3.c
@@ -1009,7 +1009,7 @@ vmxnet3_indicate_packet(VMXNET3State *s)
 
         vmxnet3_dump_rx_descr(&rxd);
 
-        if (0 != ready_rxcd_pa) {
+        if (ready_rxcd_pa != 0) {
             cpu_physical_memory_write(ready_rxcd_pa, &rxcd, sizeof(rxcd));
         }
 
@@ -1020,7 +1020,7 @@ vmxnet3_indicate_packet(VMXNET3State *s)
         rxcd.gen = new_rxcd_gen;
         rxcd.rqID = RXQ_IDX + rx_ridx * s->rxq_num;
 
-        if (0 == bytes_left) {
+        if (bytes_left == 0) {
             vmxnet3_rx_update_descr(s->rx_pkt, &rxcd);
         }
 
@@ -1038,16 +1038,16 @@ vmxnet3_indicate_packet(VMXNET3State *s)
         num_frags++;
     }
 
-    if (0 != ready_rxcd_pa) {
+    if (ready_rxcd_pa != 0) {
         rxcd.eop = 1;
-        rxcd.err = (0 != bytes_left);
+        rxcd.err = (bytes_left != 0);
         cpu_physical_memory_write(ready_rxcd_pa, &rxcd, sizeof(rxcd));
 
         /* Flush RX descriptor changes */
         smp_wmb();
     }
 
-    if (0 != new_rxcd_pa) {
+    if (new_rxcd_pa != 0) {
         vmxnet3_revert_rxc_descr(s, RXQ_IDX);
     }
 
@@ -1190,8 +1190,8 @@ static void vmxnet3_update_mcast_filters(VMXNET3State *s)
     s->mcast_list_len = list_bytes / sizeof(s->mcast_list[0]);
 
     s->mcast_list = g_realloc(s->mcast_list, list_bytes);
-    if (NULL == s->mcast_list) {
-        if (0 == s->mcast_list_len) {
+    if (!s->mcast_list) {
+        if (s->mcast_list_len == 0) {
             VMW_CFPRN("Current multicast list is empty");
         } else {
             VMW_ERPRN("Failed to allocate multicast list of %d elements",
@@ -1667,7 +1667,7 @@ vmxnet3_io_bar1_write(void *opaque,
          * memory address. We save it to temp variable and set the
          * shared address only after we get the high part
          */
-        if (0 == val) {
+        if (val == 0) {
             s->device_active = false;
         }
         s->temp_shared_guest_driver_memory = val;
-- 
1.7.12.4

Re: [Qemu-devel] [PATCH v4 0/8] don't use Yoda conditions

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 877 bytes --]

On 08/04/2014 03:19 AM, arei.gonglei@huawei.com wrote:
> From: Gonglei <arei.gonglei@huawei.com>
> 
> $WHATEVER: don't use 'Yoda conditions'
> 
> 'Yoda conditions' are not part of idiomatic QEMU coding
> style, so rewrite them in the more usual order.
> 
> v4:
>  - trivial typo for patch 1/8 suggested by Eric, thanks.

Series: Reviewed-by: Eric Blake <eblake@redhat.com>

Adding qemu-trivial in cc.

> Gonglei (8):
>   CODING_STYLE: Section about conditional statement
>   usb: don't use 'Yoda conditions'
>   audio: don't use 'Yoda conditions'
>   isa-bus: don't use 'Yoda conditions'
>   don't use 'Yoda conditions'
>   spice: don't use 'Yoda conditions'
>   vl: don't use 'Yoda conditions'
>   vmxnet3: don't use 'Yoda conditions'
> 


-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


[-- Attachment #2: OpenPGP digital signature --]
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Re: [Qemu-devel] [PATCH v4 0/8] don't use Yoda conditions

[Gonglei (Arei)]

Hi,

> >
> > $WHATEVER: don't use 'Yoda conditions'
> >
> > 'Yoda conditions' are not part of idiomatic QEMU coding
> > style, so rewrite them in the more usual order.
> >
> > v4:
> >  - trivial typo for patch 1/8 suggested by Eric, thanks.
> 
> Series: Reviewed-by: Eric Blake <eblake@redhat.com>
> 
> Adding qemu-trivial in cc.
> 
Thanks for review, Eric.

> > Gonglei (8):
> >   CODING_STYLE: Section about conditional statement
> >   usb: don't use 'Yoda conditions'
> >   audio: don't use 'Yoda conditions'
> >   isa-bus: don't use 'Yoda conditions'
> >   don't use 'Yoda conditions'
> >   spice: don't use 'Yoda conditions'
> >   vl: don't use 'Yoda conditions'
> >   vmxnet3: don't use 'Yoda conditions'
> >
> 
> 
> --
> Eric Blake   eblake redhat com    +1-919-301-3266
> Libvirt virtualization library http://libvirt.org

Best regards,
-Gonglei