GNѧϰ¼Ç¼

\" (for literal quote)
\$ (for literal dollars sign)
\\ (for literal backslash)

a = "mypath"
b = "$a/foo.cc" # b -> "mypath/foo.cc"
c = "foo${a}bar.cc" # c -> "foomypathbar.cc"

a = [ "first" ]
a += [ "second" ] # [ "first", "second" ]
a += [ "third", "fourth" ] # [ "first", "second", "third", "fourth" ]
b = a + [ "fifth" ] # [ "first", "second", "third", "fourth", "fifth" ]

a = [ "first", "second", "third", "first" ]
b = a - [ "first" ] # [ "second", "third" ]
a -= [ "second" ] # [ "first", "third", "first" ]

a = [ "first", "second", "third" ]
b = a[1] # -> "second"

a = [ "one" ]
a = [ "two" ] # Error: overwriting nonempty list with a nonempty list.
a = [] # OK
a = [ "two" ] # OK

if (is_linux || (is_win && target_cpu == "x86")) {
sources -= [ "something.cc" ]
} else if (...) {
...
} else {
...
}

foreach(i, mylist) {
print(i) # Note: i is a copy of each element, not a reference to it.
}

print("hello, world")
assert(is_win, "This should only be executed on Windows")

static_library("mylibrary") {
sources = [ "a.cc" ]
}

> gn gen out/Default 
Done.
> touch base/BUILD.gn
> ninja -C out/Default base
[1/1] Regenerating ninja files
[101/323] CXX obj/base/icu_utf.o
...
> gn clean out/Default

static_library(¡°base¡±) {
  sources = [
    ¡°a.cc¡±,
    ¡°b.cc¡±,
  ]
}

static_library(¡°base¡±) {
  sources = [
    ¡°a.cc¡±,
    ¡°b.cc¡±,
  ]

  deps = [
    ¡°//fancypants¡±,
    ¡°//foo/bar:baz¡±,
  ]
}

Full label
//chrome/browser:version
¡ú ÔÚ/¸ùĿ¼/chrome/browser/BUILD.gnÀïËÑË÷version

Implicit name
//base
¡ú //base:baseµÄËõд£¬ÔÚ/¸ùĿ¼/base/BUILD.gnÀïËÑË÷base

In current file
:baz
¡ú ÔÚµ±Ç°µÄBUILD.gnÀïËÑË÷baz

executable, shared_library, static_library
loadable_module: ÔËÐÐʱ¼ÓÔØÄ£¿é£¬ÀàËÆshared_library
source_set: ±àÒëµÄÔ´Îļþ£¬ÕâЩԴÎļþ²»»á¹¹½¨³öÖмä

group: Ò»×é±»ÃüÃûµÄ¹¹½¨Ä¿±ê
copy
action, action _foreach: Ö´Ðнű¾
bundle_data, create_bundle: Mac & iOS

component(¡°base¡±) {
  sources = [
    ¡°a.cc¡±,
    ¡°b.cc¡±,
  ]

  if (is_win || is_linux) {
    sources += [ ¡°win_helper.cc¡± ]
  } else {
    sources -= [ ¡°a.cc¡± ]
  }
}

executable(¡°doom_melon¡±) {
  sources = [ ¡°doom_melon.cc¡± ]

  cflags = [ ¡°-Wall¡± ]
  defines = [ ¡°EVIL_BIT=1¡± ]
  include_dirs = [ ¡°.¡± ]

  deps = [ ¡°//base¡± ]
}

config(¡°myconfig¡±) {
  defines = [ ¡°EVIL_BIT=1¡± ]
}

executable(¡°doom_melon¡±) {
  ...
  configs += [ ¡°:myconfig¡± ]
}

test(¡°doom_melon_tests¡±) {
  ...
  configs += [ ¡°:myconfig¡± ]
}

config(¡°icu_dirs¡±) {
include_dirs = [ ¡°include¡± ]
}

shared_library(¡°icu¡±) {
public_configs = [ ¡°:icu_dirs¡± ]
}

executable(¡°doom_melon¡±) {
deps = [
# Apply ICU¡¯s public_configs.
¡°:icu¡±,
]
}

shared_library(¡°i18n_utils¡±) {
¡­
public_deps = [
¡°//third_party/icu¡±,
]
}

executable(¡°doom_melon¡±) {
deps = [
# Apply ICU¡¯s public_configs.
¡°:i18n_utils¡±,
]
}

> gn desc out/Default //base
¡­ <lots o¡¯ stuff> ¡­

> gn desc out/Default
//tools/gn deps --tree
//base:base
//base:base_paths
//base:base_static
//base:build_date
//base:copy_dbghelp.dll
//base:debugging_flags
//base/allocator:allocator
//base/allocator:allocator_shim
//base/allocator:prep_libc
//base/third_party/dynamic_annotations:dynamic_annotations
//base/trace_event/etw_manifest:chrome_events_win
//build/config/sanitizers:deps
//third_party/modp_b64:modp_b64
//build/config/sanitizers:deps
//tools/gn:gn_lib
//base:base...
//base/third_party/dynamic_annotations:dynamic_annotations
//tools/gn:last_commit_position

> gn ls out/Default ¡°//base/*¡±
//base:base
//base:base_i18n_perftests
//base:base_i18n_perftests_run
//base:base_paths
//base:base_perftests
//base:base_perftests_run
//base:base_static
//base:base_unittests
//base:base_unittests_bundle_data
//base:base_unittests_run
//base:build_date
//base:build_utf8_validator_tables
//base:check_example
//base:debugging_flags
//base:i18n
//base:message_loop_tests
//base/allocator:allocator
//base/allocator:features
//base/allocator:tcmalloc

> gn path out/Default
//content/browser //cc/base

//content/browser:browser --[private]-->
//cc:cc --[private]-->
//cc/base:base

Showing one of 118 unique non-data paths.
0 of them are public.
Use --all to print all paths.

> gn refs out/Default //cc
//ash:ash
//ash/mus:lib
//blimp/client:blimp_client
...

> gn refs out/Default //cc --tree
//media/blink:blink
//media/blink:media_blink_unittests
//media/blink:media_blink_unittests_run
...

> gn refs out/Default
//base/macros.h
//base:base

> gn check out/Default

ERROR at //base/files/file_path.cc
#include "sql/statement.h"
^--------------
It is not in any dependency of
//base:base
The include file is in the target(s):
//sql:sql
which should somehow be reachable.

executable(¡°doom_melon¡±) {
print(configs)
...
}

> gn gen out/Default

["//build/config:feature_flags",
"//build/config/compiler:compiler",
"//build/config/compiler:clang_stackrealign",
"//build/config/compiler:compiler_arm_fpu",
"//build/config/compiler:chromium_code",
"//build/config/compiler:default_include_dirs",
"//build/config/compiler:default_optimization", "//build/config/compiler:default_symbols",
"//build/config/compiler:no_rtti",
"//build/config/compiler:runtime_library",
"//build/config/sanitizers:default_sanitizer_flags",
"//build/config/sanitizers:default_sanitizer_coverage_flags",
"//build/config/win:lean_and_mean",
"//build/config/win:nominmax",
"//build/config/win:unicode",
"//build/config/win:winver",
"//build/config:debug"]

executable(¡°doom_melon¡±) {
configs -= [
"//build/config/compiler:chromium_code",
]
configs += [
"//build/config/compiler:no_chromium_code",
]
}

declare_args() {
# Allow unlimited requests
# to the Google speech API.
bypass_speech_api_quota = false
}


executable(¡°doom_melon¡±) {
if (bypass_speech_api_quota) {
¡­
}
}

> gn args out/Default

bypass_speech_api_quota = true
is_debug = false
is_component_build = true

> gn args --list out/Default

v8_use_snapshot Default = true
//v8/BUILD.gn:23
Enable the snapshot feature, for fast context creation.
http://v8project.blogspot.com/2015/09/custom-startup-snapshots.html

visual_studio_path Default = ""
//build/config/win/visual_studio_version.gni:9
Path to Visual Studio. If empty, the default is used which is to use the
automatic toolchain in depot_tools. If set, you must also set the
visual_studio_version and wdk_path.

visual_studio_version Default = ""
//build/config/win/visual_studio_version.gni:13
Version of Visual Studio pointed to by the visual_studio_path.
Use "2013" for Visual Studio 2013, or "2013e" for the Express version.

wdk_path Default = ""
//build/config/win/visual_studio_version.gni:17
Directory of the Windows driver kit. If visual_studio_path is empty, this
will be auto-filled.

win_console_app Default = false
//build/config/win/console_app.gni:12
If true, builds as a console app (rather than a windowed app), which allows
logging to be printed to the user. This will cause a terminal window to pop
up when the executable is not run from the command line, so should only be
used for development. Only has an effect on Windows builds.

windows_sdk_path Default = "C:\Program Files (x86)\Windows Kits\10"
//build/config/win/visual_studio_version.gni:22
Full path to the Windows SDK, not including a backslash at the end.
This value is the default location, override if you have a different
installation location.

declare_args() {
# Controls Chrome branding.
is_chrome_branded = false
}

enable_crashing = is_win

import(¡°//foo/build.gni¡±)

executable(¡°doom_melon¡±) {
if (is_chrome_branded) {
¡­
}
if (enable_crashing) {
¡­ 
}
}