Re: [Qemu-devel] [PATCH 2/3] blockdev: Add dynamic generation of module_block.h

[Fam Zheng <famz@redhat.com>]

On Wed, 06/22 17:35, Colin Lord wrote:
> From: Marc Mari <markmb@redhat.com>
> 
> To simplify the addition of new block modules, add a script that generates
> include/qemu/module_block.h automatically from the modules' source code.
> 
> This script assumes that the QEMU coding style rules are followed.
> 
> Signed-off-by: Marc Mari <markmb@redhat.com>
> Signed-off-by: Colin Lord <clord@redhat.com>
> ---
>  .gitignore                      |   1 +
>  Makefile                        |   8 +++
>  scripts/modules/module_block.py | 134 ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 143 insertions(+)
>  create mode 100644 scripts/modules/module_block.py
> 
> diff --git a/.gitignore b/.gitignore
> index 38ee1c5..06aa064 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -110,3 +110,4 @@ tags
>  TAGS
>  docker-src.*
>  *~
> +/include/qemu/module_block.h
> diff --git a/Makefile b/Makefile
> index ed4032a..8f8b6a2 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -76,6 +76,8 @@ GENERATED_HEADERS += trace/generated-ust-provider.h
>  GENERATED_SOURCES += trace/generated-ust.c
>  endif
>  
> +GENERATED_HEADERS += include/qemu/module_block.h
> +
>  # Don't try to regenerate Makefile or configure
>  # We don't generate any of them
>  Makefile: ;
> @@ -352,6 +354,12 @@ ivshmem-client$(EXESUF): $(ivshmem-client-obj-y) libqemuutil.a libqemustub.a
>  ivshmem-server$(EXESUF): $(ivshmem-server-obj-y) libqemuutil.a libqemustub.a
>  	$(call LINK, $^)
>  
> +include/qemu/module_block.h: $(SRC_PATH)/scripts/modules/module_block.py config-host.mak
> +	$(call quiet-command,$(PYTHON) \
> +$(SRC_PATH)/scripts/modules/module_block.py \
> +	$(SRC_PATH)/"./include/qemu/" $(addprefix $(SRC_PATH)/,$(patsubst %.mo,%.c,$(block-obj-m))), \

Please don't generate the header under $(SRC_PATH), instead generate in the
build dir. And the rule body should use $@ instead of repeating the target
name.

> +	"  GEN   $@")
> +
>  clean:
>  # avoid old build problems by removing potentially incorrect old files
>  	rm -f config.mak op-i386.h opc-i386.h gen-op-i386.h op-arm.h opc-arm.h gen-op-arm.h
> diff --git a/scripts/modules/module_block.py b/scripts/modules/module_block.py
> new file mode 100644
> index 0000000..2b5d24c
> --- /dev/null
> +++ b/scripts/modules/module_block.py
> @@ -0,0 +1,134 @@
> +#!/usr/bin/python
> +#
> +# Module information generator
> +#
> +# Copyright Red Hat, Inc. 2015

* 2015 - 2016

> +#
> +# Authors:
> +#  Marc Mari <markmb@redhat.com>
> +#
> +# This work is licensed under the terms of the GNU GPL, version 2.
> +# See the COPYING file in the top-level directory.
> +
> +from __future__ import print_function
> +import sys
> +import os
> +
> +def get_string_struct(line):
> +    data = line.split()
> +
> +    # data[0] -> struct element name
> +    # data[1] -> =
> +    # data[2] -> value
> +
> +    return data[2].replace('"', '')[:-1]
> +
> +def add_module(fheader, library, format_name, protocol_name,
> +                probe, probe_device):
> +    lines = []
> +    lines.append('.library_name = "' + library + '",')
> +    if format_name != "":
> +        lines.append('.format_name = "' + format_name + '",')
> +    if protocol_name != "":
> +        lines.append('.protocol_name = "' + protocol_name + '",')
> +    if probe:
> +        lines.append('.has_probe = true,')
> +    if probe_device:
> +        lines.append('.has_probe_device = true,')
> +
> +    text = '\n\t'.join(lines)
> +    fheader.write('\n\t{\n\t' + text + '\n\t},')
> +
> +def process_file(fheader, filename):
> +    # This parser assumes the coding style rules are being followed
> +    with open(filename, "r") as cfile:
> +        found_something = False
> +        found_start = False
> +        library, _ = os.path.splitext(os.path.basename(filename))
> +        for line in cfile:
> +            if found_start:
> +                line = line.replace('\n', '')
> +                if line.find(".format_name") != -1:
> +                    format_name = get_string_struct(line)
> +                elif line.find(".protocol_name") != -1:
> +                    protocol_name = get_string_struct(line)
> +                elif line.find(".bdrv_probe") != -1:
> +                    probe = True
> +                elif line.find(".bdrv_probe_device") != -1:
> +                    probe_device = True
> +                elif line == "};":
> +                    add_module(fheader, library, format_name, protocol_name,
> +                                probe, probe_device)
> +                    found_start = False
> +            elif line.find("static BlockDriver") != -1:
> +                found_something = True
> +                found_start = True
> +                format_name = ""
> +                protocol_name = ""
> +                probe = False
> +                probe_device = False
> +
> +        if not found_something:
> +            print("No BlockDriver struct found in " + filename + ". \
> +                    Is this really a module?", file=sys.stderr)
> +            sys.exit(1)
> +
> +def print_top(fheader):
> +    fheader.write('''/* AUTOMATICALLY GENERATED, DO NOT MODIFY */
> +/*
> + * QEMU Block Module Infrastructure
> + *
> + * Copyright Red Hat, Inc. 2015

* 2015 - 2016

> + *
> + * Authors:
> + *  Marc Mari       <markmb@redhat.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + *
> + */
> +
> +''')
> +
> +    fheader.write('''#ifndef QEMU_MODULE_BLOCK_H
> +#define QEMU_MODULE_BLOCK_H
> +
> +#include "qemu-common.h"
> +
> +static const struct {
> +    const char *format_name;
> +    const char *protocol_name;
> +    const char *library_name;
> +    bool has_probe;
> +    bool has_probe_device;
> +} block_driver_modules[] = {''')
> +
> +def print_bottom(fheader):
> +    fheader.write('''
> +};
> +
> +#endif
> +''')
> +
> +# First argument: output folder
> +# All other arguments: modules source files (.c)
> +output_dir = sys.argv[1]
> +if not os.path.isdir(output_dir):
> +    print("Folder " + output_dir + " does not exist", file=sys.stderr)
> +    sys.exit(1)

Please just treat sys.argv[1] as the full path of output file, no need to
hardcode "module_block.h".

> +
> +path = output_dir + 'module_block.h'
> +
> +with open(path, 'w') as fheader:
> +    print_top(fheader)
> +
> +    for filename in sys.argv[2:]:
> +        if os.path.isfile(filename):
> +            process_file(fheader, filename)
> +        else:
> +            print("File " + filename + " does not exist.", file=sys.stderr)
> +            sys.exit(1)
> +
> +    print_bottom(fheader)
> +
> +sys.exit(0)
> -- 
> 2.5.5
> 
> 

Fam