premake5 主要由 lua 写成，修改了 lua 加载脚本的方式，将工程用到的 lua 脚本统统转换为 C 代码的字节数组并加载之。
对于一些变动不大的通用的库的来说，改为字节数组加载更方便。
premake5 提供了一个 premake-core/scripts/embed.lua 用于生成脚本到字节数组，我们修改之为己所用。
修改过的 embed.lua
--
-- Embed the Lua scripts into src/host/scripts.c as static data buffers.
-- Embeds minified versions of the actual scripts by default, rather than
-- bytecode, as bytecodes are not portable to different architectures. Use
-- the `--bytecode` flag to override.
--
local scriptCount = 0
local function loadScript(fname)
fname = path.getabsolute(fname)
local f = io.open(fname, "rb")
local s = assert(f:read("*all"))
f:close()
return s
end
local function stripScript(s)
-- strip tabs
local result = s:gsub("[\t]", "")
-- strip any CRs
result = result:gsub("[\r]", "")
-- strip out block comments
result = result:gsub("[^\"']%-%-%[%[.-%]%]", "")
result = result:gsub("[^\"']%-%-%[=%[.-%]=%]", "")
sresult = result:gsub("[^\"']%-%-%[==%[.-%]==%]", "")
-- strip out inline comments
result = result:gsub("\n%-%-[^\n]*", "\n")
-- strip duplicate line feeds
result = result:gsub("\n+", "\n")
-- strip out leading comments
result = result:gsub("^%-%-[^\n]*\n", "")
return result
end
local function outputScript(result, script)
local data = script.data
local length = #data
if length > 0 then
script.table = string.format("builtin_script_%d", scriptCount)
scriptCount = scriptCount + 1
buffered.writeln(result, "// ".. script.name)
buffered.writeln(result, "static const unsigned char " .. script.table .. "[] = {")
for i = 1, length do
buffered.write(result, string.format("%3d, ", data:byte(i)))
if (i % 32 == 0) then
buffered.writeln(result)
end
end
buffered.writeln(result, "};")
buffered.writeln(result)
end
end
local function addScript(result, filename, name, data)
if not data then
if _OPTIONS["bytecode"] then
verbosef("Compiling... " .. filename)
local output = path.replaceextension(filename, ".luac")
local res, err = os.compile(filename, output);
if res ~= nil then
data = loadScript(output)
os.remove(output)
else
print(err)
print("Embedding source instead.")
data = stripScript(loadScript(filename))
end
else
data = stripScript(loadScript(filename))
end
end
local script = {}
script.filename = filename
script.name = name
script.data = data
table.insert(result, script)
end
-- Prepare the file header
local result = buffered.new()
buffered.writeln(result, "/* Premake's Lua scripts, as static data buffers for release mode builds */")
buffered.writeln(result, "/* DO NOT EDIT - this file is autogenerated - see BUILD.txt */")
buffered.writeln(result, "/* To regenerate this file, run: premake5 embed */")
buffered.writeln(result, "")
buffered.writeln(result, '#include "host/premake.h"')
buffered.writeln(result, "")
-- Find all of the _manifest.lua files within the project
local mask = path.join(_MAIN_SCRIPT_DIR, "**/_manifest.lua")
local manifests = os.matchfiles(mask)
-- Generate table of embedded content.
local contentTable = {}
print("Compiling... ")
for mi = 1, #manifests do
local manifestName = manifests[mi]
local manifestDir = path.getdirectory(manifestName)
local baseDir = path.getdirectory(manifestDir)
local files = dofile(manifests[mi])
for fi = 1, #files do
local filename = path.join(manifestDir, files[fi])
addScript(contentTable, filename, path.getrelative(baseDir, filename))
end
end
--addScript(contentTable, path.join(_SCRIPT_DIR, "../src/_premake_main.lua"), "src/_premake_main.lua")
addScript(contentTable, path.join(_SCRIPT_DIR, "./lua/_manifest.lua"), "lua/_manifest.lua")
-- Embed the actual script contents
print("Embedding...")
for mi = 1, #contentTable do
outputScript(result, contentTable[mi])
end
-- Generate an index of the script file names. Script names are stored
-- relative to the directory containing the manifest, i.e. the main
-- Xcode script, which is at $/modules/xcode/xcode.lua is stored as
-- "xcode/xcode.lua".
buffered.writeln(result, "const buildin_mapping builtin_scripts[] = {")
for mi = 1, #contentTable do
if contentTable[mi].table then
buffered.writeln(result, string.format('\t{"%s", %s, sizeof(%s)},', contentTable[mi].name, contentTable[mi].table, contentTable[mi].table))
else
buffered.writeln(result, string.format('\t{"%s", NULL, 0},', contentTable[mi].name))
end
end
buffered.writeln(result, "\t{NULL, NULL, 0}")
buffered.writeln(result, "};")
buffered.writeln(result, "")
-- Write it all out. Check against the current contents of scripts.c first,
-- and only overwrite it if there are actual changes.
print("Writing...")
local scriptsFile = path.getabsolute(path.join(_SCRIPT_DIR, "./scripts.c"))
local output = buffered.tostring(result)
local f, err = os.writefile_ifnotequal(output, scriptsFile);
if (f < 0) then
error(err, 0)
elseif (f > 0) then
printf("Generated %s...", path.getrelative(os.getcwd(), scriptsFile))
end
我们的脚本目录结构
lua\util001.lua
lua\_manifest.lua
embed.lua
在 _manifest.lua 中修改需要生成的脚本文件名
return
{
"util001.lua"
}
运行以下命令会在 embed.lua 所在目录生成 scripts.c
premake5 --file=embed.lua
生成的 scripts.c
/* Premake's Lua scripts, as static data buffers for release mode builds */
/* DO NOT EDIT - this file is autogenerated - see BUILD.txt */
/* To regenerate this file, run: premake5 embed */
#include "host/premake.h"
// lua/util001.lua
static const unsigned char builtin_script_0[] = {
108, 111, 99, 97, 108, 32, 117, 116, 105, 108, 32, 61, 32, 123, 125, 10, 32, 10, 102, 117, 110, 99, 116, 105, 111, 110, 32, 117, 116, 105, 108, 46,
116, 101, 115, 116, 40, 97, 114, 103, 41, 10, 32, 32, 32, 32, 112, 114, 105, 110, 116, 40, 97, 114, 103, 41, 10, 101, 110, 100, 10, 32, 10, 114,
101, 116, 117, 114, 110, 32, 117, 116, 105, 108, };
// lua/_manifest.lua
static const unsigned char builtin_script_1[] = {
114, 101, 116, 117, 114, 110, 10, 123, 10, 32, 32, 32, 32, 32, 32, 32, 32, 45, 45, 32, 99, 106, 115, 111, 110, 10, 32, 32, 32, 32, 32, 32,
32, 32, 45, 45, 34, 99, 106, 115, 111, 110, 47, 117, 116, 105, 108, 46, 108, 117, 97, 34, 44, 10, 32, 32, 32, 32, 32, 32, 32, 32, 45, 45,
34, 66, 105, 110, 68, 101, 99, 72, 101, 120, 46, 108, 117, 97, 34, 44, 10, 32, 32, 32, 32, 32, 32, 32, 32, 34, 117, 116, 105, 108, 48, 48,
49, 46, 108, 117, 97, 34, 10, 125, 10, };
const buildin_mapping builtin_scripts[] = {
{"lua/util001.lua", builtin_script_0, sizeof(builtin_script_0)},
{"lua/_manifest.lua", builtin_script_1, sizeof(builtin_script_1)},
{NULL, NULL, 0}
};
下一节修改自己的 lua 引擎加载代码。