1 #!/usr/bin/env python 2 3 """ 4 Encoder functions, producing representations of program objects. 5 6 Copyright (C) 2016 Paul Boddie <paul@boddie.org.uk> 7 8 This program is free software; you can redistribute it and/or modify it under 9 the terms of the GNU General Public License as published by the Free Software 10 Foundation; either version 3 of the License, or (at your option) any later 11 version. 12 13 This program is distributed in the hope that it will be useful, but WITHOUT 14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 15 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more 16 details. 17 18 You should have received a copy of the GNU General Public License along with 19 this program. If not, see <http://www.gnu.org/licenses/>. 20 """ 21 22 from common import first 23 24 # Output encoding and decoding for the summary files. 25 26 def encode_attrnames(attrnames): 27 28 "Encode the 'attrnames' representing usage." 29 30 return ", ".join(attrnames) or "{}" 31 32 def encode_constrained(constrained): 33 34 "Encode the 'constrained' status for program summaries." 35 36 return constrained and "constrained" or "deduced" 37 38 def encode_usage(usage): 39 40 "Encode attribute details from 'usage'." 41 42 all_attrnames = [] 43 for t in usage: 44 attrname, invocation, assignment = t 45 all_attrnames.append("%s%s" % (attrname, invocation and "!" or assignment and "=" or "")) 46 return ", ".join(all_attrnames) or "{}" 47 48 def decode_usage(s): 49 50 "Decode attribute details from 's'." 51 52 all_attrnames = set() 53 for attrname_str in s.split(", "): 54 all_attrnames.add((attrname_str.rstrip("!="), attrname_str.endswith("!"), attrname_str.endswith("="))) 55 56 all_attrnames = list(all_attrnames) 57 all_attrnames.sort() 58 return tuple(all_attrnames) 59 60 def encode_access_location(t): 61 62 "Encode the access location 't'." 63 64 path, name, attrname, version = t 65 return "%s %s %s:%d" % (path, name or "{}", attrname, version) 66 67 def encode_location(t): 68 69 "Encode the general location 't' in a concise form." 70 71 path, name, attrname, version = t 72 if name is not None and version is not None: 73 return "%s %s:%d" % (path, name, version) 74 elif name is not None: 75 return "%s %s" % (path, name) 76 else: 77 return "%s :%s" % (path, attrname) 78 79 def encode_modifiers(modifiers): 80 81 "Encode assignment details from 'modifiers'." 82 83 all_modifiers = [] 84 for t in modifiers: 85 all_modifiers.append(encode_modifier_term(t)) 86 return "".join(all_modifiers) 87 88 def encode_modifier_term(t): 89 90 "Encode modifier 't' representing assignment status." 91 92 assignment, invocation = t 93 return assignment and "=" or invocation and "!" or "_" 94 95 def decode_modifier_term(s): 96 97 "Decode modifier term 's' representing assignment status." 98 99 return (s == "=", s == "!") 100 101 102 103 # Test generation functions. 104 105 def get_kinds(all_types): 106 107 """ 108 Return object kind details for 'all_types', being a collection of 109 references for program types. 110 """ 111 112 return map(lambda ref: ref.get_kind(), all_types) 113 114 def test_for_kind(prefix, kind): 115 116 "Return a test condition identifier featuring 'prefix' and 'kind'." 117 118 return "%s-%s" % (prefix, kind == "<instance>" and "instance" or "type") 119 120 def test_for_kinds(prefix, all_kinds): 121 122 """ 123 Return an identifier describing test conditions incorporating the given 124 'prefix' and involving 'all_kinds', being a collection of object kinds. 125 """ 126 127 return test_for_kind(prefix, first(all_kinds)) 128 129 def test_for_type(prefix, ref): 130 131 """ 132 Return an identifier describing a test condition incorporating the given 133 'prefix' and involving 'ref', being a program type reference. The kind of 134 the reference is employed in the identifier. 135 """ 136 137 return test_for_kind(prefix, ref.get_kind()) 138 139 140 141 # Instruction representation encoding. 142 143 def encode_instruction(instruction): 144 145 """ 146 Encode the 'instruction' - a sequence starting with an operation and 147 followed by arguments, each of which may be an instruction sequence or a 148 plain value - to produce a function call string representation. 149 """ 150 151 op = instruction[0] 152 args = instruction[1:] 153 154 if args: 155 a = [] 156 for arg in args: 157 if isinstance(arg, tuple): 158 a.append(encode_instruction(arg)) 159 else: 160 a.append(arg or "{}") 161 argstr = "(%s)" % ", ".join(a) 162 return "%s%s" % (op, argstr) 163 else: 164 return op 165 166 167 168 # Output program encoding. 169 170 attribute_ops = ( 171 "__load_via_class", "__load_via_object", 172 "__store_via_object", 173 ) 174 175 checked_ops = ( 176 "__check_and_load_via_class", "__check_and_load_via_object", "__check_and_load_via_any", 177 "__check_and_store_via_class", "__check_and_store_via_object", "__check_and_store_via_any", 178 ) 179 180 typename_ops = ( 181 "__test_common_instance", 182 ) 183 184 encoding_ops = ( 185 "__encode_callable", 186 ) 187 188 def encode_access_instruction(instruction, subs): 189 190 """ 191 Encode the 'instruction' - a sequence starting with an operation and 192 followed by arguments, each of which may be an instruction sequence or a 193 plain value - to produce a function call string representation. 194 195 The 'subs' parameter defines a mapping of substitutions for special values 196 used in instructions. 197 """ 198 199 op = instruction[0] 200 args = instruction[1:] 201 202 if not args: 203 argstr = "" 204 205 else: 206 # Encode the arguments. 207 208 a = [] 209 for arg in args: 210 a.append(encode_access_instruction_arg(arg, subs)) 211 212 # Modify certain arguments. 213 214 # Convert attribute name arguments to position symbols. 215 216 if op in attribute_ops: 217 arg = a[1] 218 a[1] = encode_symbol("pos", arg) 219 220 # Convert attribute name arguments to position and code symbols. 221 222 elif op in checked_ops: 223 arg = a[1] 224 a[1] = encode_symbol("pos", arg) 225 a.insert(2, encode_symbol("code", arg)) 226 227 # Convert type name arguments to position and code symbols. 228 229 elif op in typename_ops: 230 arg = "#" % a[1] 231 a[1] = encode_symbol("pos", arg) 232 a.insert(2, encode_symbol("code", arg)) 233 234 # Replace encoded operations. 235 236 elif op in encoding_ops: 237 origin = a[0] 238 kind = a[1] 239 op = "__load_function" 240 a = [kind == "<class>" and encode_instantiator_pointer(origin) or encode_function_pointer(origin)] 241 242 argstr = "(%s)" % ", ".join(a) 243 244 # Substitute the first element of the instruction, which may not be an 245 # operation at all. 246 247 return "%s%s" % (subs.get(op, op), argstr) 248 249 def encode_access_instruction_arg(arg, subs): 250 251 "Encode 'arg' using 'subs' to define substitutions." 252 253 if isinstance(arg, tuple): 254 return encode_access_instruction(arg, subs) 255 256 # Special values only need replacing, not encoding. 257 258 elif subs.has_key(arg): 259 return subs.get(arg) 260 261 # Other values may need encoding. 262 263 else: 264 return encode_path(arg) 265 266 def encode_function_pointer(path): 267 268 "Encode 'path' as a reference to an output program function." 269 270 return "__fn_%s" % encode_path(path) 271 272 def encode_instantiator_pointer(path): 273 274 "Encode 'path' as a reference to an output program instantiator." 275 276 return "__new_%s" % encode_path(path) 277 278 def encode_path(path): 279 280 "Encode 'path' as an output program object, translating special symbols." 281 282 if path in reserved_words: 283 return "__%s" % path 284 else: 285 return path.replace("#", "__").replace("$", "__").replace(".", "_") 286 287 def encode_symbol(symbol_type, path=None): 288 289 "Encode a symbol with the given 'symbol_type' and optional 'path'." 290 291 return "__%s%s" % (symbol_type, path and "_%s" % encode_path(path) or "") 292 293 294 295 # Output language reserved words. 296 297 reserved_words = [ 298 "break", "char", "const", "continue", 299 "default", "double", "else", 300 "float", "for", 301 "if", "int", "long", 302 "NULL", 303 "return", "struct", 304 "typedef", 305 "void", "while", 306 ] 307 308 # vim: tabstop=4 expandtab shiftwidth=4