test: fix the cimport method

This commit will hopefully allow the cimport method to be used just as one
would use #inclue <header.h> in C. It follows the following method:

1. create a pseudoheader file that #include's all the requested header files
2. runs the pseudoheader through the C preprocessor (it will try various
   compilers if available on the system).
3. runs the preprocessed file through a C formatter, which attempts to group
   statements on one line. For example, a struct definition that was
   formerly on several lines will take just one line after formatting. This
   is done so that unique declarations can be detected. Duplicates are thus
   easy to remove.
4. remove lines that are too complex for the LuaJIT C parser (such as:
   Objective-C block syntax, crazy enums defined on linux, ...)
5. remove duplicate declarations
6. pass result to ffi.cdef

1 files changed, 155 insertions, 0 deletions

diff --git a/test/unit/preprocess.moon b/test/unit/preprocess.moon
new file mode 100644
index 0000000000..88580476b2
--- /dev/null
+++ b/test/unit/preprocess.moon
@@ -0,0 +1,155 @@
+-- helps managing loading different headers into the LuaJIT ffi. Untested on
+-- windows, will probably need quite a bit of adjustment to run there.
+
+ffi = require("ffi")
+
+ccs = {}
+
+env_cc = os.getenv("CC")
+if env_cc
+  table.insert(ccs, {path: "/usr/bin/env #{env_cc}", type: "gcc"})
+
+if ffi.os == "Windows"
+  table.insert(ccs, {path: "cl", type: "msvc"})
+
+table.insert(ccs, {path: "/usr/bin/env cc", type: "gcc"})
+table.insert(ccs, {path: "/usr/bin/env gcc", type: "gcc"})
+table.insert(ccs, {path: "/usr/bin/env gcc-4.9", type: "gcc"})
+table.insert(ccs, {path: "/usr/bin/env gcc-4.8", type: "gcc"})
+table.insert(ccs, {path: "/usr/bin/env gcc-4.7", type: "gcc"})
+table.insert(ccs, {path: "/usr/bin/env clang", type: "clang"})
+table.insert(ccs, {path: "/usr/bin/env icc", type: "gcc"})
+
+quote_me = '[^%w%+%-%=%@%_%/]' -- complement (needn't quote)
+shell_quote = (str) ->
+  if string.find(str, quote_me) or str == '' then
+    "'" .. string.gsub(str, "'", [['"'"']]) .. "'"
+  else
+    str
+
+-- parse Makefile format dependencies into a Lua table
+parse_make_deps = (deps) ->
+  -- remove line breaks and line concatenators
+  deps = deps\gsub("\n", "")\gsub("\\", "")
+
+  -- remove the Makefile "target:" element
+  deps = deps\gsub(".+:", "")
+
+  -- remove redundant spaces
+  deps = deps\gsub("  +", " ")
+
+  -- split acording to token (space in this case)
+  headers = {}
+  for token in deps\gmatch("[^%s]+")
+    -- headers[token] = true
+    headers[#headers + 1] = token
+
+  -- resolve path redirections (..) to normalize all paths
+  for i, v in ipairs(headers)
+    -- double dots (..)
+    headers[i] = v\gsub("/[^/%s]+/%.%.", "")
+
+    -- single dot (.)
+    headers[i] = v\gsub("%./", "")
+
+  headers
+
+-- will produce a string that represents a meta C header file that includes
+-- all the passed in headers. I.e.:
+--
+-- headerize({"stdio.h", "math.h", true}
+-- produces:
+-- #include <stdio.h>
+-- #include <math.h>
+--
+-- headerize({"vim.h", "memory.h", false}
+-- produces:
+-- #include "vim.h"
+-- #include "memory.h"
+headerize = (headers, global) ->
+  pre = '"'
+  post = pre
+  if global
+    pre = "<"
+    post = ">"
+
+  formatted = ["#include #{pre}#{hdr}#{post}" for hdr in *headers]
+  table.concat(formatted, "\n")
+
+class Gcc
+  -- preprocessor flags that will hopefully make the compiler produce C
+  -- declarations that the LuaJIT ffi understands.
+  @@preprocessor_extra_flags = {
+   '-D "aligned(ARGS)="',
+   '-D "__attribute__(ARGS)="',
+   '-D "__asm(ARGS)="',
+   '-D "__asm__(ARGS)="',
+   '-D "__inline__="',
+   '-D_GNU_SOURCE'
+  }
+
+  new: (path) =>
+    @path = path
+
+  add_to_include_path: (...) =>
+      paths = {...}
+      for path in *paths
+          directive = '-I ' .. '"' .. path .. '"'
+          @@preprocessor_extra_flags[#@@preprocessor_extra_flags + 1] = directive
+
+  -- returns a list of the headers files upon which this file relies
+  dependencies: (hdr) =>
+    out = io.popen("#{@path} -M #{hdr} 2>&1")
+    deps = out\read("*a")
+    out\close!
+
+    if deps
+      parse_make_deps(deps)
+    else
+      nil
+
+  -- returns a stream representing a preprocessed form of the passed-in
+  -- headers. Don't forget to close the stream by calling the close() method
+  -- on it.
+  preprocess_stream: (...) =>
+    paths = {...}
+    -- create pseudo-header
+    pseudoheader = headerize(paths, false)
+    defines = table.concat(@@preprocessor_extra_flags, ' ')
+    cmd = ("echo $hdr | #{@path} #{defines} -std=c99 -P -E -")\gsub('$hdr', shell_quote(pseudoheader))
+    -- lfs = require("lfs")
+    -- print("CWD: #{lfs.currentdir!}")
+    -- print("CMD: #{cmd}")
+    -- io.stderr\write("CWD: #{lfs.currentdir!}\n")
+    -- io.stderr\write("CMD: #{cmd}\n")
+    io.popen(cmd)
+
+class Clang extends Gcc
+class Msvc extends Gcc
+
+type_to_class = {
+  "gcc": Gcc,
+  "clang": Clang,
+  "msvc": Msvc
+}
+
+find_best_cc = (ccs) ->
+  for _, meta in pairs(ccs)
+    version = io.popen("#{meta.path} -v 2>&1")
+    version\close!
+    if version
+      return type_to_class[meta.type](meta.path)
+  nil
+
+-- find the best cc. If os.exec causes problems on windows (like popping up
+-- a console window) we might consider using something like this:
+-- http://scite-ru.googlecode.com/svn/trunk/pack/tools/LuaLib/shell.html#exec
+cc = nil
+if cc == nil
+  cc = find_best_cc(ccs)
+
+return {
+  includes: (hdr) -> cc\dependencies(hdr)
+  preprocess_stream: (...) -> cc\preprocess_stream(...)
+  add_to_include_path: (...) -> cc\add_to_include_path(...)
+}