Add requirement parser (#286)

mmcv/version.py

 # Copyright (c) Open-MMLab. All rights reserved.
-__version__ = '0.5.3'
+__version__ = '0.5.4'

setup.py

@@ -22,15 +22,6 @@ def choose_requirement(primary, secondary):
     return str(primary)
 
 
-install_requires = ['addict', 'numpy', 'pyyaml', 'yapf']
-
-# If first not installed install second package
-CHOOSE_INSTALL_REQUIRES = [('opencv-python-headless>=3', 'opencv-python>=3')]
-
-for main, secondary in CHOOSE_INSTALL_REQUIRES:
-    install_requires.append(choose_requirement(main, secondary))
-
-
 def readme():
     with open('README.rst', encoding='utf-8') as f:
         content = f.read()
@@ -44,6 +35,92 @@ def get_version():
     return locals()['__version__']
 
 
+def parse_requirements(fname='requirements.txt', with_version=True):
+    """
+    Parse the package dependencies listed in a requirements file but strips
+    specific versioning information.
+
+    Args:
+        fname (str): path to requirements file
+        with_version (bool, default=False): if True include version specs
+
+    Returns:
+        List[str]: list of requirements items
+
+    CommandLine:
+        python -c "import setup; print(setup.parse_requirements())"
+    """
+    import sys
+    from os.path import exists
+    import re
+    require_fpath = fname
+
+    def parse_line(line):
+        """
+        Parse information from a line in a requirements text file
+        """
+        if line.startswith('-r '):
+            # Allow specifying requirements in other files
+            target = line.split(' ')[1]
+            for info in parse_require_file(target):
+                yield info
+        else:
+            info = {'line': line}
+            if line.startswith('-e '):
+                info['package'] = line.split('#egg=')[1]
+            else:
+                # Remove versioning from the package
+                pat = '(' + '|'.join(['>=', '==', '>']) + ')'
+                parts = re.split(pat, line, maxsplit=1)
+                parts = [p.strip() for p in parts]
+
+                info['package'] = parts[0]
+                if len(parts) > 1:
+                    op, rest = parts[1:]
+                    if ';' in rest:
+                        # Handle platform specific dependencies
+                        # http://setuptools.readthedocs.io/en/latest/setuptools.html#declaring-platform-specific-dependencies
+                        version, platform_deps = map(str.strip,
+                                                     rest.split(';'))
+                        info['platform_deps'] = platform_deps
+                    else:
+                        version = rest  # NOQA
+                    info['version'] = (op, version)
+            yield info
+
+    def parse_require_file(fpath):
+        with open(fpath, 'r') as f:
+            for line in f.readlines():
+                line = line.strip()
+                if line and not line.startswith('#'):
+                    for info in parse_line(line):
+                        yield info
+
+    def gen_packages_items():
+        if exists(require_fpath):
+            for info in parse_require_file(require_fpath):
+                parts = [info['package']]
+                if with_version and 'version' in info:
+                    parts.extend(info['version'])
+                if not sys.version.startswith('3.4'):
+                    # apparently package_deps are broken in 3.4
+                    platform_deps = info.get('platform_deps')
+                    if platform_deps is not None:
+                        parts.append(';' + platform_deps)
+                item = ''.join(parts)
+                yield item
+
+    packages = list(gen_packages_items())
+    return packages
+
+
+# If first not installed install second package
+CHOOSE_INSTALL_REQUIRES = [('opencv-python-headless>=3', 'opencv-python>=3')]
+
+install_requires = parse_requirements()
+for main, secondary in CHOOSE_INSTALL_REQUIRES:
+    install_requires.append(choose_requirement(main, secondary))
+
 if platform.system() == 'Darwin':
     extra_compile_args = ['-stdlib=libc++']
     extra_link_args = ['-stdlib=libc++']