BranchInterpreter::getScriptBranches() - Code Metrics - Inspection of "Script conditional branches" - Bit-Wasp/bitcoin-php - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#492)

by thomas

created 2017-08-05 21:28 UTC

BranchInterpreter::getScriptBranches() A

↳ Parent: BranchInterpreter

Complexity

Conditions	3
Paths	2

Size

Total Lines	16
Code Lines	10

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	3
eloc	10
nc	2
nop	1
dl	0
loc	16
rs	9.4285
c	0
b	0
f	0

<?php

namespace BitWasp\Bitcoin\Script\Path;

use BitWasp\Bitcoin\Script\Interpreter\Stack;
use BitWasp\Bitcoin\Script\Opcodes;
use BitWasp\Bitcoin\Script\ScriptInterface;

class BranchInterpreter
{

    /**
     * @var array
     */
    private $disabledOps = [
        Opcodes::OP_CAT,    Opcodes::OP_SUBSTR, Opcodes::OP_LEFT,  Opcodes::OP_RIGHT,
        Opcodes::OP_INVERT, Opcodes::OP_AND,    Opcodes::OP_OR,    Opcodes::OP_XOR,
        Opcodes::OP_2MUL,   Opcodes::OP_2DIV,   Opcodes::OP_MUL,   Opcodes::OP_DIV,
        Opcodes::OP_MOD,    Opcodes::OP_LSHIFT, Opcodes::OP_RSHIFT
    ];

    /**
     * @param ScriptInterface $script
     * @return ScriptBranch[]
     */
    public function getScriptBranches(ScriptInterface $script)
    {
        $ast = $this->getAstForLogicalOps($script);
        $paths = $ast->flags();
        $results = [];

        if (count($paths) > 1) {
            foreach ($paths as $path) {
                $results[] = $this->getBranchForPath($script, $path);
            }
        } else {
            $results[] = $this->getBranchForPath($script, []);
        }

        return $results;
    }

    /**
     * Build tree of dependent logical ops
     * @param ScriptInterface $script
     * @return LogicOpNode
     */
    public function getAstForLogicalOps(ScriptInterface $script)
    {
        $root = new LogicOpNode(null);
        $nextId = 1;
        $current = $root;
        $segments = [$root];

        foreach ($script->getScriptParser()->decode() as $op) {
            switch ($op->getOp()) {
                case Opcodes::OP_IF:
                    list ($node0, $node1) = $current->split();
                    $segments[$nextId++] = $node0;
                    $segments[$nextId++] = $node1;
                    $current = $node1;
                    break;
                case Opcodes::OP_NOTIF:
                    list ($node0, $node1) = $current->split();
                    $segments[$nextId++] = $node0;
                    $segments[$nextId++] = $node1;
                    $current = $node0;
                    break;
                case Opcodes::OP_ENDIF:
                    $current = $current->getParent();
                    break;
                case Opcodes::OP_ELSE:
                    if ($current->getValue() === false) {
                        throw new \RuntimeException("Unbalanced conditional");
                    }
                    $current = $current->getParent()->getChild(0);
                    break;
            }
        }

        return $root;
    }

    /**
     * Given a script and path, attempt to produce a ScriptBranch instance
     *
     * @param ScriptInterface $script
     * @param bool[] $path
     * @return ScriptBranch
     */
    public function getBranchForPath(ScriptInterface $script, array $path)
    {
        $stack = new Stack();
        foreach (array_reverse($path) as $setting) {
            $stack->push($setting);
        }

        $segments = $this->evaluateUsingStack($script, $stack);
        return new ScriptBranch($script, $path, $segments);
    }

    /**
     * @param Stack $vfStack
     * @param bool $value
     * @return bool
     */
    private function checkExec(Stack $vfStack, $value)
    {
        $ret = 0;
        foreach ($vfStack as $item) {
            if ($item === $value) {
                $ret++;
            }
        }

        return $ret;
    }

    /**
     * @param ScriptInterface $script
     * @param Stack $mainStack
     * @return PathTrace
     */
    public function evaluateUsingStack(ScriptInterface $script, Stack $mainStack)
    {
        $vfStack = new Stack();
        $parser = $script->getScriptParser();
        $tracer = new PathTracer();

        foreach ($parser as $i => $operation) {
            $opCode = $operation->getOp();
            $fExec = !$this->checkExec($vfStack, false);

            if (in_array($opCode, $this->disabledOps, true)) {
                throw new \RuntimeException('Disabled Opcode');
            }

            if (Opcodes::OP_IF <= $opCode && $opCode <= Opcodes::OP_ENDIF) {
                switch ($opCode) {
                    case Opcodes::OP_IF:
                    case Opcodes::OP_NOTIF:
                        // <expression> if [statements] [else [statements]] endif
                        $value = false;
                        if ($fExec) {
                            if ($mainStack->isEmpty()) {
                                throw new \RuntimeException('Unbalanced conditional');
                            }

                            $value = $mainStack->pop();
                            if ($opCode === Opcodes::OP_NOTIF) {
                                $value = !$value;
                            }
                        }
                        $vfStack->push($value);
                        break;

                    case Opcodes::OP_ELSE:
                        if ($vfStack->isEmpty()) {
                            throw new \RuntimeException('Unbalanced conditional');
                        }
                        $vfStack->push(!$vfStack->pop());
                        break;

                    case Opcodes::OP_ENDIF:
                        if ($vfStack->isEmpty()) {
                            throw new \RuntimeException('Unbalanced conditional');
                        }
                        $vfStack->pop();

                        break;
                }

                $tracer->operation($operation);
            } else if ($fExec) {
                // Fill up trace with executed opcodes
                $tracer->operation($operation);
            }
        }

        if (count($vfStack) !== 0) {
            throw new \RuntimeException('Unbalanced conditional at script end');
        }

        if (count($mainStack) !== 0) {
            throw new \RuntimeException('Values remaining after script execution - invalid branch data');
        }

        return $tracer->done();
    }
}


1			<?php
2
3			namespace BitWasp\Bitcoin\Script\Path;
4
5			use BitWasp\Bitcoin\Script\Interpreter\Stack;
6			use BitWasp\Bitcoin\Script\Opcodes;
7			use BitWasp\Bitcoin\Script\ScriptInterface;
8
9			class BranchInterpreter
10			{
11
12			/**
13			* @var array
14			*/
15			private $disabledOps = [
16			Opcodes::OP_CAT, Opcodes::OP_SUBSTR, Opcodes::OP_LEFT, Opcodes::OP_RIGHT,
17			Opcodes::OP_INVERT, Opcodes::OP_AND, Opcodes::OP_OR, Opcodes::OP_XOR,
18			Opcodes::OP_2MUL, Opcodes::OP_2DIV, Opcodes::OP_MUL, Opcodes::OP_DIV,
19			Opcodes::OP_MOD, Opcodes::OP_LSHIFT, Opcodes::OP_RSHIFT
20			];
21
22			/**
23			* @param ScriptInterface $script
24			* @return ScriptBranch[]
25			*/
26			public function getScriptBranches(ScriptInterface $script)
27			{
28			$ast = $this->getAstForLogicalOps($script);
29			$paths = $ast->flags();
30			$results = [];
31
32			if (count($paths) > 1) {
33			foreach ($paths as $path) {
34			$results[] = $this->getBranchForPath($script, $path);
35			}
36			} else {
37			$results[] = $this->getBranchForPath($script, []);
38			}
39
40			return $results;
41			}
42
43			/**
44			* Build tree of dependent logical ops
45			* @param ScriptInterface $script
46			* @return LogicOpNode
47			*/
48			public function getAstForLogicalOps(ScriptInterface $script)
49			{
50			$root = new LogicOpNode(null);
51			$nextId = 1;
52			$current = $root;
53			$segments = [$root];
54
55			foreach ($script->getScriptParser()->decode() as $op) {
56			switch ($op->getOp()) {
57			case Opcodes::OP_IF:
58			list ($node0, $node1) = $current->split();
59			$segments[$nextId++] = $node0;
60			$segments[$nextId++] = $node1;
61			$current = $node1;
62			break;
63			case Opcodes::OP_NOTIF:
64			list ($node0, $node1) = $current->split();
65			$segments[$nextId++] = $node0;
66			$segments[$nextId++] = $node1;
67			$current = $node0;
68			break;
69			case Opcodes::OP_ENDIF:
70			$current = $current->getParent();
71			break;
72			case Opcodes::OP_ELSE:
73			if ($current->getValue() === false) {
74			throw new \RuntimeException("Unbalanced conditional");
75			}
76			$current = $current->getParent()->getChild(0);
77			break;
78			}
79			}
80
81			return $root;
82			}
83
84			/**
85			* Given a script and path, attempt to produce a ScriptBranch instance
86			*
87			* @param ScriptInterface $script
88			* @param bool[] $path
89			* @return ScriptBranch
90			*/
91			public function getBranchForPath(ScriptInterface $script, array $path)
92			{
93			$stack = new Stack();
94			foreach (array_reverse($path) as $setting) {
95			$stack->push($setting);
96			}
97
98			$segments = $this->evaluateUsingStack($script, $stack);
99			return new ScriptBranch($script, $path, $segments);
100			}
101
102			/**
103			* @param Stack $vfStack
104			* @param bool $value
105			* @return bool
106			*/
107			private function checkExec(Stack $vfStack, $value)
108			{
109			$ret = 0;
110			foreach ($vfStack as $item) {
111			if ($item === $value) {
112			$ret++;
113			}
114			}
115
116			return $ret;
117			}
118
119			/**
120			* @param ScriptInterface $script
121			* @param Stack $mainStack
122			* @return PathTrace
123			*/
124			public function evaluateUsingStack(ScriptInterface $script, Stack $mainStack)
125			{
126			$vfStack = new Stack();
127			$parser = $script->getScriptParser();
128			$tracer = new PathTracer();
129
130			foreach ($parser as $i => $operation) {
131			$opCode = $operation->getOp();
132			$fExec = !$this->checkExec($vfStack, false);
133
134			if (in_array($opCode, $this->disabledOps, true)) {
135			throw new \RuntimeException('Disabled Opcode');
136			}
137
138			if (Opcodes::OP_IF <= $opCode && $opCode <= Opcodes::OP_ENDIF) {
139			switch ($opCode) {
140			case Opcodes::OP_IF:
141			case Opcodes::OP_NOTIF:
142			// <expression> if [statements] [else [statements]] endif
143			$value = false;
144			if ($fExec) {
145			if ($mainStack->isEmpty()) {
146			throw new \RuntimeException('Unbalanced conditional');
147			}
148
149			$value = $mainStack->pop();
150			if ($opCode === Opcodes::OP_NOTIF) {
151			$value = !$value;
152			}
153			}
154			$vfStack->push($value);
155			break;
156
157			case Opcodes::OP_ELSE:
158			if ($vfStack->isEmpty()) {
159			throw new \RuntimeException('Unbalanced conditional');
160			}
161			$vfStack->push(!$vfStack->pop());
162			break;
163
164			case Opcodes::OP_ENDIF:
165			if ($vfStack->isEmpty()) {
166			throw new \RuntimeException('Unbalanced conditional');
167			}
168			$vfStack->pop();
169
170			break;
171			}
172
173			$tracer->operation($operation);
174			} else if ($fExec) {
175			// Fill up trace with executed opcodes
176			$tracer->operation($operation);
177			}
178			}
179
180			if (count($vfStack) !== 0) {
181			throw new \RuntimeException('Unbalanced conditional at script end');
182			}
183
184			if (count($mainStack) !== 0) {
185			throw new \RuntimeException('Values remaining after script execution - invalid branch data');
186			}
187
188			return $tracer->done();
189			}
190			}
191

Bit-Wasp / bitcoin-php

Pull Request — master (#492)

BranchInterpreter::getScriptBranches() A

Complexity

Size

Duplication

Importance

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