<?php
namespace JmesPath;
/**
* Tree visitor used to compile JMESPath expressions into native PHP code.
*/
class TreeCompiler
{
private $indentation;
private $source;
private $vars;
/**
* @param array $ast AST to compile.
* @param string $fnName The name of the function to generate.
* @param string $expr Expression being compiled.
*
* @return string
*/
public function visit(array $ast, $fnName, $expr)
{
$this->vars = [];
$this->source = $this->indentation = '';
$this->write("<?php\n")
->write('use JmesPath\\TreeInterpreter as Ti;')
->write('use JmesPath\\FnDispatcher as Fn;')
->write('use JmesPath\\Utils;')
->write('')
->write('function %s(Ti $interpreter, $value) {', $fnName)
->indent()
->dispatch($ast)
->write('')
->write('return $value;')
->outdent()
->write('}');
return $this->source;
}
/**
* @param array $node
* @return mixed
*/
private function dispatch(array $node)
{
return $this->{"visit_{$node['type']}"}($node);
}
/**
* Creates a monotonically incrementing unique variable name by prefix.
*
* @param string $prefix Variable name prefix
*
* @return string
*/
private function makeVar($prefix)
{
if (!isset($this->vars[$prefix])) {
$this->vars[$prefix] = 0;
return '$' . $prefix;
}
return '$' . $prefix . ++$this->vars[$prefix];
}
/**
* Writes the given line of source code. Pass positional arguments to write
* that match the format of sprintf.
*
* @param string $str String to write
* @return $this
*/
private function write($str)
{
$this->source .= $this->indentation;
if (func_num_args() == 1) {
$this->source .= $str . "\n";
return $this;
}
$this->source .= vsprintf($str, array_slice(func_get_args(), 1)) . "\n";
return $this;
}
/**
* Decreases the indentation level of code being written
* @return $this
*/
private function outdent()
{
$this->indentation = substr($this->indentation, 0, -4);
return $this;
}
/**
* Increases the indentation level of code being written
* @return $this
*/
private function indent()
{
$this->indentation .= ' ';
return $this;
}
private function visit_or(array $node)
{
$a = $this->makeVar('beforeOr');
return $this
->write('%s = $value;', $a)
->dispatch($node['children'][0])
->write('if (!$value && $value !== "0" && $value !== 0) {')
->indent()
->write('$value = %s;', $a)
->dispatch($node['children'][1])
->outdent()
->write('}');
}
private function visit_and(array $node)
{
$a = $this->makeVar('beforeAnd');
return $this
->write('%s = $value;', $a)
->dispatch($node['children'][0])
->write('if ($value || $value === "0" || $value === 0) {')
->indent()
->write('$value = %s;', $a)
->dispatch($node['children'][1])
->outdent()
->write('}');
}
private function visit_not(array $node)
{
return $this
->write('// Visiting not node')
->dispatch($node['children'][0])
->write('// Applying boolean not to result of not node')
->write('$value = !Utils::isTruthy($value);');
}
private function visit_subexpression(array $node)
{
return $this
->dispatch($node['children'][0])
->write('if ($value !== null) {')
->indent()
->dispatch($node['children'][1])
->outdent()
->write('}');
}
private function visit_field(array $node)
{
$arr = '$value[' . var_export($node['value'], true) . ']';
$obj = '$value->{' . var_export($node['value'], true) . '}';
$this->write('if (is_array($value) || $value instanceof \\ArrayAccess) {')
->indent()
->write('$value = isset(%s) ? %s : null;', $arr, $arr)
->outdent()
->write('} elseif ($value instanceof \\stdClass) {')
->indent()
->write('$value = isset(%s) ? %s : null;', $obj, $obj)
->outdent()
->write("} else {")
->indent()
->write('$value = null;')
->outdent()
->write("}");
return $this;
}
private function visit_index(array $node)
{
if ($node['value'] >= 0) {
$check = '$value[' . $node['value'] . ']';
return $this->write(
'$value = (is_array($value) || $value instanceof \\ArrayAccess)'
. ' && isset(%s) ? %s : null;',
$check, $check
);
}
$a = $this->makeVar('count');
return $this
->write('if (is_array($value) || ($value instanceof \\ArrayAccess && $value instanceof \\Countable)) {')
->indent()
->write('%s = count($value) + %s;', $a, $node['value'])
->write('$value = isset($value[%s]) ? $value[%s] : null;', $a, $a)
->outdent()
->write('} else {')
->indent()
->write('$value = null;')
->outdent()
->write('}');
}
private function visit_literal(array $node)
{
return $this->write('$value = %s;', var_export($node['value'], true));
}
private function visit_pipe(array $node)
{
return $this
->dispatch($node['children'][0])
->dispatch($node['children'][1]);
}
private function visit_multi_select_list(array $node)
{
return $this->visit_multi_select_hash($node);
}
private function visit_multi_select_hash(array $node)
{
$listVal = $this->makeVar('list');
$value = $this->makeVar('prev');
$this->write('if ($value !== null) {')
->indent()
->write('%s = [];', $listVal)
->write('%s = $value;', $value);
$first = true;
foreach ($node['children'] as $child) {
if (!$first) {
$this->write('$value = %s;', $value);
}
$first = false;
if ($node['type'] == 'multi_select_hash') {
$this->dispatch($child['children'][0]);
$key = var_export($child['value'], true);
$this->write('%s[%s] = $value;', $listVal, $key);
} else {
$this->dispatch($child);
$this->write('%s[] = $value;', $listVal);
}
}
return $this
->write('$value = %s;', $listVal)
->outdent()
->write('}');
}
private function visit_function(array $node)
{
$value = $this->makeVar('val');
$args = $this->makeVar('args');
$this->write('%s = $value;', $value)
->write('%s = [];', $args);
foreach ($node['children'] as $arg) {
$this->dispatch($arg);
$this->write('%s[] = $value;', $args)
->write('$value = %s;', $value);
}
return $this->write(
'$value = Fn::getInstance()->__invoke("%s", %s);',
$node['value'], $args
);
}
private function visit_slice(array $node)
{
return $this
->write('$value = !is_string($value) && !Utils::isArray($value)')
->write(' ? null : Utils::slice($value, %s, %s, %s);',
var_export($node['value'][0], true),
var_export($node['value'][1], true),
var_export($node['value'][2], true)
);
}
private function visit_current(array $node)
{
return $this->write('// Visiting current node (no-op)');
}
private function visit_expref(array $node)
{
$child = var_export($node['children'][0], true);
return $this->write('$value = function ($value) use ($interpreter) {')
->indent()
->write('return $interpreter->visit(%s, $value);', $child)
->outdent()
->write('};');
}
private function visit_flatten(array $node)
{
$this->dispatch($node['children'][0]);
$merged = $this->makeVar('merged');
$val = $this->makeVar('val');
$this
->write('// Visiting merge node')
->write('if (!Utils::isArray($value)) {')
->indent()
->write('$value = null;')
->outdent()
->write('} else {')
->indent()
->write('%s = [];', $merged)
->write('foreach ($value as %s) {', $val)
->indent()
->write('if (is_array(%s) && isset(%s[0])) {', $val, $val)
->indent()
->write('%s = array_merge(%s, %s);', $merged, $merged, $val)
->outdent()
->write('} elseif (%s !== []) {', $val)
->indent()
->write('%s[] = %s;', $merged, $val)
->outdent()
->write('}')
->outdent()
->write('}')
->write('$value = %s;', $merged)
->outdent()
->write('}');
return $this;
}
private function visit_projection(array $node)
{
$val = $this->makeVar('val');
$collected = $this->makeVar('collected');
$this->write('// Visiting projection node')
->dispatch($node['children'][0])
->write('');
if (!isset($node['from'])) {
$this->write('if (!is_array($value) || !($value instanceof \stdClass)) { $value = null; }');
} elseif ($node['from'] == 'object') {
$this->write('if (!Utils::isObject($value)) { $value = null; }');
} elseif ($node['from'] == 'array') {
$this->write('if (!Utils::isArray($value)) { $value = null; }');
}
$this->write('if ($value !== null) {')
->indent()
->write('%s = [];', $collected)
->write('foreach ((array) $value as %s) {', $val)
->indent()
->write('$value = %s;', $val)
->dispatch($node['children'][1])
->write('if ($value !== null) {')
->indent()
->write('%s[] = $value;', $collected)
->outdent()
->write('}')
->outdent()
->write('}')
->write('$value = %s;', $collected)
->outdent()
->write('}');
return $this;
}
private function visit_condition(array $node)
{
$value = $this->makeVar('beforeCondition');
return $this
->write('%s = $value;', $value)
->write('// Visiting condition node')
->dispatch($node['children'][0])
->write('// Checking result of condition node')
->write('if (Utils::isTruthy($value)) {')
->indent()
->write('$value = %s;', $value)
->dispatch($node['children'][1])
->outdent()
->write('} else {')
->indent()
->write('$value = null;')
->outdent()
->write('}');
}
private function visit_comparator(array $node)
{
$value = $this->makeVar('val');
$a = $this->makeVar('left');
$b = $this->makeVar('right');
$this
->write('// Visiting comparator node')
->write('%s = $value;', $value)
->dispatch($node['children'][0])
->write('%s = $value;', $a)
->write('$value = %s;', $value)
->dispatch($node['children'][1])
->write('%s = $value;', $b);
if ($node['value'] == '==') {
$this->write('$value = Utils::isEqual(%s, %s);', $a, $b);
} elseif ($node['value'] == '!=') {
$this->write('$value = !Utils::isEqual(%s, %s);', $a, $b);
} else {
$this->write(
'$value = is_int(%s) && is_int(%s) && %s %s %s;',
$a, $b, $a, $node['value'], $b
);
}
return $this;
}
/** @internal */
public function __call($method, $args)
{
throw new \RuntimeException(
sprintf('Invalid node encountered: %s', json_encode($args[0]))
);
}
}
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