Build rclone binaries from source

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "rclone/src/github.com/ncw/rclone"]
+	path = rclone/src/github.com/ncw/rclone
+	url = git@github.com:rclone/rclone.git

app/.gitignore

@@ -1 +1,2 @@
 /build
+/lib

rclone/.gitignore

@@ -0,0 +1,2 @@
+gobuild/
+pkg/

rclone/build-rclone.py

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+# Adapted from syncthing-android
+
+from __future__ import print_function
+import os
+import os.path
+import sys
+import subprocess
+import platform
+
+SUPPORTED_PYTHON_PLATFORMS = ['Windows', 'Linux', 'Darwin']
+
+BUILD_TARGETS = [
+    {
+        'arch': 'arm',
+        'goarch': 'arm',
+        'binary_directory': 'armabi-v7a',
+        'cc': 'arm-linux-androideabi-clang',
+    },
+    {
+        'arch': 'arm64',
+        'goarch': 'arm64',
+        'binary_directory': 'arm64-v8a',
+        'cc': 'aarch64-linux-android-clang',
+        'min_sdk': 21,
+    },
+    {
+        'arch': 'x86',
+        'goarch': '386',
+        'binary_directory': 'x86',
+        'cc': 'i686-linux-android-clang',
+    },
+    {
+        'arch': 'x86_64',
+        'goarch': 'amd64',
+        'binary_directory': 'x86_64',
+        'cc': 'x86_64-linux-android-clang',
+    }
+]
+
+
+def fail(message, *args, **kwargs):
+    print((message % args).format(**kwargs))
+    sys.exit(1)
+
+
+def get_min_sdk(project_dir):
+    with open(os.path.join(project_dir, 'app', 'build.gradle')) as file_handle:
+        for line in file_handle:
+            tokens = list(filter(None, line.split()))
+            if len(tokens) == 2 and tokens[0] == 'minSdkVersion':
+                return int(tokens[1])
+
+    fail('Failed to find minSdkVersion')
+
+
+def get_ndk_home():
+    if not os.environ.get('ANDROID_NDK_HOME', ''):
+        fail('ANDROID_NDK_HOME environment variable not defined')
+    return os.environ['ANDROID_NDK_HOME']
+
+
+if platform.system() not in SUPPORTED_PYTHON_PLATFORMS:
+    fail(
+        'Unsupported python platform %s. Supported platforms: %s',
+        platform.system(),
+        ', '.join(SUPPORTED_PYTHON_PLATFORMS),
+    )
+
+module_dir = os.path.dirname(os.path.realpath(__file__))
+project_dir = os.path.realpath(os.path.join(module_dir, '..'))
+# Use seperate build dir so standalone ndk isn't deleted by `gradle clean`
+build_dir = os.path.join(module_dir, 'gobuild')
+go_build_dir = os.path.join(build_dir, 'go-packages')
+rclone_dir = os.path.join(module_dir, 'src', 'github.com', 'ncw', 'rclone')
+min_sdk = get_min_sdk(project_dir)
+
+subprocess.check_call(['git', '-C', rclone_dir, 'fetch', '--tags'])
+
+for target in BUILD_TARGETS:
+    target_min_sdk = str(target.get('min_sdk', min_sdk))
+    print('Building for', target['arch'])
+
+    if os.environ.get('RCLONE_ANDROID_PREBUILT', ''):
+        # The environment variable indicates the SDK and stdlib was prebuilt,
+        # set a custom paths.
+        standalone_ndk_dir = '%s/standalone-ndk/android-%s-%s' % (
+            get_ndk_home(), target_min_sdk, target['goarch'],
+        )
+        pkg_argument = []
+    else:
+        # Build standalone NDK toolchain if it doesn't exist.
+        # https://developer.android.com/ndk/guides/standalone_toolchain.html
+        standalone_ndk_dir = '%s/standalone-ndk/android-%s-%s' % (
+            build_dir, target_min_sdk, target['goarch'],
+        )
+        pkg_argument = ['-pkgdir', os.path.join(go_build_dir, target['goarch'])]
+
+    if not os.path.isdir(standalone_ndk_dir):
+        print('Building standalone NDK for', target['arch'], 'API level', target_min_sdk, 'to', standalone_ndk_dir)
+        subprocess.check_call(
+            [
+                sys.executable,
+                os.path.join(get_ndk_home(), 'build', 'tools', 'make_standalone_toolchain.py'),
+                '--arch',
+                target['arch'],
+                '--api',
+                target_min_sdk,
+                '--install-dir',
+                standalone_ndk_dir,
+                '-v',
+            ]
+        )
+
+    print('Building rclone for %s' % target['arch'])
+
+    environ = os.environ.copy()
+    environ.update(
+        {
+            'GOPATH': module_dir,
+            'GO111MODULE': 'on',
+            'CGO_ENABLED': '1',
+            'GOOS': 'android',
+            'GOARCH': target['goarch'],
+            'CC': os.path.join(standalone_ndk_dir, 'bin', target['cc']),
+        }
+    )
+
+    subprocess.check_call(['go', 'mod', 'download'], cwd=rclone_dir)
+    subprocess.check_call(['go', 'build', '-v', '-tags', 'linux'] + pkg_argument, env=environ, cwd=rclone_dir)
+
+    # Copy compiled binary to jniLibs folder
+    target_dir = os.path.join(project_dir, 'app', 'lib', target['binary_directory'])
+    if not os.path.isdir(target_dir):
+        os.makedirs(target_dir)
+    target_artifact = os.path.join(target_dir, 'librclone.so')
+    if os.path.exists(target_artifact):
+        os.unlink(target_artifact)
+    os.rename(os.path.join(rclone_dir, 'rclone'), target_artifact)
+
+    print('Finished build for', target['arch'])
+
+print('All builds finished')

rclone/build.gradle

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+task buildNative(type: Exec) {
+    inputs.dir("$projectDir/src/")
+    outputs.dir("$projectDir/../app/lib/")
+    executable = 'python'
+    args = ['-u', './build-rclone.py']
+}
+
+/**
+ * Use separate task instead of standard clean(), so these folders aren't deleted by `gradle clean`.
+ */
+task cleanNative(type: Delete) {
+    delete "$projectDir/../app/lib/"
+    delete "gobuild"
+}

rclone/setup.cfg

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+[flake8]
+max-line-length = 120

settings.gradle

@@ -1 +1 @@
-include ':app', ':safdav'
+include ':app', ':safdav', ':rclone'