Windows: Make console work properly

This patch adds console functionality for the Windows build. As the Windows .exe
is a Windows subsystem executable it doesn't have a console. We solve this by
checking if there is a console of a parent process that we can attach to.
Additionally the --forceconsole parameter can be passed to force allocating a
new console if no parent console is found.

contrib/build-wine/deterministic.spec

@@ -112,8 +112,6 @@ pyz = PYZ(a.pure)
 #####
 # "standalone" exe with all dependencies packed into it
 
-#options = [ ('v', None, 'OPTION')]  - put this in the following exe list to debug and turn console=true
-
 exe_standalone = EXE(
     pyz,
     a.scripts,
@@ -125,7 +123,6 @@ exe_standalone = EXE(
     upx=False,
     icon=home+'icons/electron.ico',
     console=False)
-    # console=True makes an annoying black box pop up, but it does make Electrum output command line commands, with this turned off no output will be given but commands can still be used
 
 exe_portable = EXE(
     pyz,

contrib/deterministic-build/requirements-binaries.txt

@@ -75,3 +75,13 @@ websocket_client==0.56.0 \
 wheel==0.33.1 \
     --hash=sha256:66a8fd76f28977bb664b098372daef2b27f60dc4d1688cfab7b37a09448f0e9d \
     --hash=sha256:8eb4a788b3aec8abf5ff68d4165441bc57420c9f64ca5f471f58c3969fe08668
+psutil==5.6.1 \
+    --hash=sha256:23e9cd90db94fbced5151eaaf9033ae9667c033dffe9e709da761c20138d25b6 \
+    --hash=sha256:27858d688a58cbfdd4434e1c40f6c79eb5014b709e725c180488ccdf2f721729 \
+    --hash=sha256:354601a1d1a1322ae5920ba397c58d06c29728a15113598d1a8158647aaa5385 \
+    --hash=sha256:9c3a768486194b4592c7ae9374faa55b37b9877fd9746fb4028cb0ac38fd4c60 \
+    --hash=sha256:c1fd45931889dc1812ba61a517630d126f6185f688eac1693171c6524901b7de \
+    --hash=sha256:d463a142298112426ebd57351b45c39adb41341b91f033aa903fa4c6f76abecc \
+    --hash=sha256:e1494d20ffe7891d07d8cb9a8b306c1a38d48b13575265d090fc08910c56d474 \
+    --hash=sha256:ec4b4b638b84d42fc48139f9352f6c6587ee1018d55253542ee28db7480cc653 \
+    --hash=sha256:fa0a570e0a30b9dd618bffbece590ae15726b47f9f1eaf7518dfb35f4d7dcd21

contrib/requirements/requirements-binaries.txt

@@ -3,3 +3,4 @@ pycryptodomex<3.7
 websocket-client
 PyQt5-sip==4.19.13
 sip==4.19.8
+psutil==5.6.1

electron-cash

@@ -27,6 +27,7 @@
 # CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 import os, sys
+import ctypes
 
 # Note CashShuffle's .proto files have namespace conflicts with keepkey
 # This is a workaround to force the python implementation versus the C++
@@ -114,6 +115,7 @@ from electroncash.commands import get_parser, known_commands, Commands, config_v
 from electroncash import daemon
 from electroncash import keystore
 from electroncash.mnemonic import Mnemonic
+from electroncash.winconsole import create_or_attach_console
 import electroncash_plugins
 import electroncash.web as web
 
@@ -313,6 +315,17 @@ def init_plugins(config, gui_name):
 if __name__ == '__main__':
     # The hook will only be used in the Qt GUI right now
     util.setup_thread_excepthook()
+
+    # On windows, allocate a console if needed
+    if sys.platform.startswith('win'):
+        force_console = '-v' in sys.argv or '--verbose' in sys.argv
+        if not create_or_attach_console(create=force_console, title='Electron Cash Console') and force_console:
+            # Force console specified and we couldn't get a console, fail
+            MB_ICONERROR = 0x10
+            MB_OK = 0
+            ctypes.windll.user32.MessageBoxW(0, 'Failed to get a console', 'Electron Cash', MB_OK | MB_ICONERROR)
+            sys.exit(1)
+
     # on osx, delete Process Serial Number arg generated for apps launched in Finder
     sys.argv = list(filter(lambda x: not x.startswith('-psn'), sys.argv))
 

lib/winconsole.py

@@ -0,0 +1,90 @@
+# Electron Cash - lightweight Bitcoin client
+# Copyright (C) 2019 Axel Gembe <derago@gmail.com>
+#
+# Permission is hereby granted, free of charge, to any person
+# obtaining a copy of this software and associated documentation files
+# (the "Software"), to deal in the Software without restriction,
+# including without limitation the rights to use, copy, modify, merge,
+# publish, distribute, sublicense, and/or sell copies of the Software,
+# and to permit persons to whom the Software is furnished to do so,
+# subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+"""
+This module is for to handling console attaching and / or creation in Windows binaries that are
+built for the Windows subsystem and therefore do not automatically allocate a console.
+"""
+
+import sys
+import os
+import ctypes
+
+STD_OUTPUT_HANDLE = -11
+FILE_TYPE_DISK = 1
+
+def parent_process_pids() -> int:
+    """
+    Returns all parent process PIDs, starting with the closest parent
+    """
+    try:
+        import psutil
+        pid = os.getpid()
+        while pid > 0:
+            pid = psutil.Process(pid).ppid()
+            yield pid
+    except psutil.NoSuchProcess:
+        # Parent process not found, likely terminated, nothing we can do
+        pass
+
+def create_or_attach_console(attach: bool = True, create: bool = False, title: str = None) -> bool:
+    """
+    First this checks if output is redirected to a file and does nothing if it is. Then it tries
+    to attach to the console of any parent process and if not successful it optionally creates a
+    console or fails.
+    If a console was found or created, it will redirect current output handles to this console.
+    """
+    std_out_handle = ctypes.windll.kernel32.GetStdHandle(STD_OUTPUT_HANDLE)
+    if std_out_handle > 0:
+        if ctypes.windll.kernel32.GetFileType(std_out_handle) == FILE_TYPE_DISK:
+            # Output is being redirected to a file, do nothing
+            return
+
+    has_console = std_out_handle > 0
+
+    if not has_console and attach:
+        # Try to attach to a parent console
+        for pid in parent_process_pids():
+            if ctypes.windll.kernel32.AttachConsole(pid):
+                has_console = True
+                break
+
+    if not has_console and create:
+        # Try to allocate a new console
+        if ctypes.windll.kernel32.AllocConsole():
+            has_console = True
+
+    if not has_console:
+        return False
+
+    if title:
+        # Set the console title
+        ctypes.windll.kernel32.SetConsoleTitleW(title)
+
+    # Reopen Pythons console input and output handles
+    conout = open('CONOUT$', 'w')
+    sys.stdout = conout
+    sys.stderr = conout
+    sys.stdin = open('CONIN$', 'r')
+
+    return True