tools: generate third_party dir and symlinks from the script. (#346)

Everyone needs to run ./tools/build_third_party.py after this commit.

.gitignore

@@ -4,12 +4,5 @@
 # npm deps
 node_modules
 
-# git deps
-/third_party/v8/
-/third_party/cpplint/
-/third_party/zlib/
-/third_party/rust_crates/libc/
-/third_party/flatbuffers/
-
-# gclient files
-/third_party/.gclient_entries
+# third party deps
+/third_party/

third_party/.gclient

@@ -1 +0,0 @@
-../gclient_config.py

third_party/googletest

@@ -1 +0,0 @@
-v8/third_party/googletest

third_party/jinja2

@@ -1 +0,0 @@
-v8/third_party/jinja2

third_party/llvm-build

@@ -1 +0,0 @@
-v8/third_party/llvm-build

third_party/markupsafe

@@ -1 +0,0 @@
-v8/third_party/markupsafe

third_party/package.json

@@ -1 +0,0 @@
-../package.json

third_party/yarn.lock

@@ -1 +0,0 @@
-../yarn.lock

tools/build_third_party.py

@@ -1,5 +1,5 @@
 #!/usr/bin/env python
-# This script updates the third party dependencies of deno.
+# This script generates the third party dependencies of deno.
 # - Get Depot Tools and make sure it's in your path.
 #   http://commondatastorage.googleapis.com/chrome-infra-docs/flat/depot_tools/docs/html/depot_tools_tutorial.html#_setting_up
 # - You need yarn installed as well.
@@ -8,14 +8,26 @@
 # Use //js/package.json to modify the npm deps.
 
 import os
+from os.path import join
 import subprocess
 
 root_path = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
-third_party_path = os.path.join(root_path, "third_party")
+third_party_path = join(root_path, "third_party")
 
 
 def main():
+    try:
+        os.makedirs(third_party_path)
+    except:
+        pass
     os.chdir(third_party_path)
+    remove_and_symlink(join("..", "gclient_config.py"), ".gclient")
+    remove_and_symlink(join("..", "package.json"), "package.json")
+    remove_and_symlink(join("..", "yarn.lock"), "yarn.lock")
+    remove_and_symlink(join("v8", "third_party", "googletest"), "googletest")
+    remove_and_symlink(join("v8", "third_party", "jinja2"), "jinja2")
+    remove_and_symlink(join("v8", "third_party", "llvm-build"), "llvm-build")
+    remove_and_symlink(join("v8", "third_party", "markupsafe"), "markupsafe")
     run(["gclient", "sync", "--no-history"])
     run(["yarn"])
 
@@ -26,5 +38,30 @@ def run(args):
     subprocess.check_call(args, env=env)
 
 
+def remove_and_symlink(target, name):
+    try:
+        os.unlink(name)
+    except:
+        pass
+    os.symlink(target, name)
+
+
+def symlink(target, name, target_is_dir=False):
+    if os.name == "nt":
+        import ctypes
+        CreateSymbolicLinkW = ctypes.windll.kernel32.CreateSymbolicLinkW
+        CreateSymbolicLinkW.restype = ctypes.c_ubyte
+        CreateSymbolicLinkW.argtypes = (ctypes.c_wchar_p, ctypes.c_wchar_p,
+                                        ctypes.c_uint32)
+
+        flags = 0x02  # SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE
+        if (target_is_dir):
+            flags |= 0x01  # SYMBOLIC_LINK_FLAG_DIRECTORY
+        if not CreateSymbolicLinkW(name, target, flags):
+            raise ctypes.WinError()
+    else:
+        os.symlink(target, name)
+
+
 if '__main__' == __name__:
     main()