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<?php
/**
* Identity function, returns its argument unmodified.
*
* This is useful almost exclusively as a workaround to an oddity in the PHP
* grammar -- this is a syntax error:
*
* COUNTEREXAMPLE
* new Thing()->doStuff();
*
* ...but this works fine:
*
* id(new Thing())->doStuff();
*
* @param wild Anything.
* @return wild Unmodified argument.
*/
function id($x) {
return $x;
}
/**
* Access an array index, retrieving the value stored there if it exists or
* a default if it does not. This function allows you to concisely access an
* index which may or may not exist without raising a warning.
*
* @param array Array to access.
* @param scalar Index to access in the array.
* @param wild Default value to return if the key is not present in the
* array.
* @return wild If `$array[$key]` exists, that value is returned. If not,
* $default is returned without raising a warning.
*/
function idx(array $array, $key, $default = null) {
// isset() is a micro-optimization - it is fast but fails for null values.
if (isset($array[$key])) {
return $array[$key];
}
// Comparing $default is also a micro-optimization.
if ($default === null || array_key_exists($key, $array)) {
return null;
}
return $default;
}
/**
* Access a sequence of array indexes, retrieving a deeply nested value if
* it exists or a default if it does not.
*
* For example, `idxv($dict, array('a', 'b', 'c'))` accesses the key at
* `$dict['a']['b']['c']`, if it exists. If it does not, or any intermediate
* value is not itself an array, it returns the defualt value.
*
* @param array Array to access.
* @param list<string> List of keys to access, in sequence.
* @param wild Default value to return.
* @return wild Accessed value, or default if the value is not accessible.
*/
function idxv(array $map, array $path, $default = null) {
if (!$path) {
return $default;
}
$last = last($path);
$path = array_slice($path, 0, -1);
$cursor = $map;
foreach ($path as $key) {
$cursor = idx($cursor, $key);
if (!is_array($cursor)) {
return $default;
}
}
return idx($cursor, $last, $default);
}
/**
* Call a method on a list of objects. Short for "method pull", this function
* works just like @{function:ipull}, except that it operates on a list of
* objects instead of a list of arrays. This function simplifies a common type
* of mapping operation:
*
* COUNTEREXAMPLE
* $names = array();
* foreach ($objects as $key => $object) {
* $names[$key] = $object->getName();
* }
*
* You can express this more concisely with mpull():
*
* $names = mpull($objects, 'getName');
*
* mpull() takes a third argument, which allows you to do the same but for
* the array's keys:
*
* COUNTEREXAMPLE
* $names = array();
* foreach ($objects as $object) {
* $names[$object->getID()] = $object->getName();
* }
*
* This is the mpull version():
*
* $names = mpull($objects, 'getName', 'getID');
*
* If you pass ##null## as the second argument, the objects will be preserved:
*
* COUNTEREXAMPLE
* $id_map = array();
* foreach ($objects as $object) {
* $id_map[$object->getID()] = $object;
* }
*
* With mpull():
*
* $id_map = mpull($objects, null, 'getID');
*
* See also @{function:ipull}, which works similarly but accesses array indexes
* instead of calling methods.
*
* @param list Some list of objects.
* @param string|null Determines which **values** will appear in the result
* array. Use a string like 'getName' to store the
* value of calling the named method in each value, or
* ##null## to preserve the original objects.
* @param string|null Determines how **keys** will be assigned in the result
* array. Use a string like 'getID' to use the result
* of calling the named method as each object's key, or
* `null` to preserve the original keys.
* @return dict A dictionary with keys and values derived according
* to whatever you passed as `$method` and `$key_method`.
*/
function mpull(array $list, $method, $key_method = null) {
$result = array();
foreach ($list as $key => $object) {
if ($key_method !== null) {
$key = $object->$key_method();
}
if ($method !== null) {
$value = $object->$method();
} else {
$value = $object;
}
$result[$key] = $value;
}
return $result;
}
/**
* Access a property on a list of objects. Short for "property pull", this
* function works just like @{function:mpull}, except that it accesses object
* properties instead of methods. This function simplifies a common type of
* mapping operation:
*
* COUNTEREXAMPLE
* $names = array();
* foreach ($objects as $key => $object) {
* $names[$key] = $object->name;
* }
*
* You can express this more concisely with ppull():
*
* $names = ppull($objects, 'name');
*
* ppull() takes a third argument, which allows you to do the same but for
* the array's keys:
*
* COUNTEREXAMPLE
* $names = array();
* foreach ($objects as $object) {
* $names[$object->id] = $object->name;
* }
*
* This is the ppull version():
*
* $names = ppull($objects, 'name', 'id');
*
* If you pass ##null## as the second argument, the objects will be preserved:
*
* COUNTEREXAMPLE
* $id_map = array();
* foreach ($objects as $object) {
* $id_map[$object->id] = $object;
* }
*
* With ppull():
*
* $id_map = ppull($objects, null, 'id');
*
* See also @{function:mpull}, which works similarly but calls object methods
* instead of accessing object properties.
*
* @param list Some list of objects.
* @param string|null Determines which **values** will appear in the result
* array. Use a string like 'name' to store the value of
* accessing the named property in each value, or
* `null` to preserve the original objects.
* @param string|null Determines how **keys** will be assigned in the result
* array. Use a string like 'id' to use the result of
* accessing the named property as each object's key, or
* `null` to preserve the original keys.
* @return dict A dictionary with keys and values derived according
* to whatever you passed as `$property` and
* `$key_property`.
*/
function ppull(array $list, $property, $key_property = null) {
$result = array();
foreach ($list as $key => $object) {
if ($key_property !== null) {
$key = $object->$key_property;
}
if ($property !== null) {
$value = $object->$property;
} else {
$value = $object;
}
$result[$key] = $value;
}
return $result;
}
/**
* Choose an index from a list of arrays. Short for "index pull", this function
* works just like @{function:mpull}, except that it operates on a list of
* arrays and selects an index from them instead of operating on a list of
* objects and calling a method on them.
*
* This function simplifies a common type of mapping operation:
*
* COUNTEREXAMPLE
* $names = array();
* foreach ($list as $key => $dict) {
* $names[$key] = $dict['name'];
* }
*
* With ipull():
*
* $names = ipull($list, 'name');
*
* See @{function:mpull} for more usage examples.
*
* @param list Some list of arrays.
* @param scalar|null Determines which **values** will appear in the result
* array. Use a scalar to select that index from each
* array, or null to preserve the arrays unmodified as
* values.
* @param scalar|null Determines which **keys** will appear in the result
* array. Use a scalar to select that index from each
* array, or null to preserve the array keys.
* @return dict A dictionary with keys and values derived according
* to whatever you passed for `$index` and `$key_index`.
*/
function ipull(array $list, $index, $key_index = null) {
$result = array();
foreach ($list as $key => $array) {
if ($key_index !== null) {
$key = $array[$key_index];
}
if ($index !== null) {
$value = $array[$index];
} else {
$value = $array;
}
$result[$key] = $value;
}
return $result;
}
/**
* Group a list of objects by the result of some method, similar to how
* GROUP BY works in an SQL query. This function simplifies grouping objects
* by some property:
*
* COUNTEREXAMPLE
* $animals_by_species = array();
* foreach ($animals as $animal) {
* $animals_by_species[$animal->getSpecies()][] = $animal;
* }
*
* This can be expressed more tersely with mgroup():
*
* $animals_by_species = mgroup($animals, 'getSpecies');
*
* In either case, the result is a dictionary which maps species (e.g., like
* "dog") to lists of animals with that property, so all the dogs are grouped
* together and all the cats are grouped together, or whatever super
* businessesey thing is actually happening in your problem domain.
*
* See also @{function:igroup}, which works the same way but operates on
* array indexes.
*
* @param list List of objects to group by some property.
* @param string Name of a method, like 'getType', to call on each object
* in order to determine which group it should be placed into.
* @param ... Zero or more additional method names, to subgroup the
* groups.
* @return dict Dictionary mapping distinct method returns to lists of
* all objects which returned that value.
*/
function mgroup(array $list, $by /* , ... */) {
$map = mpull($list, $by);
$groups = array();
foreach ($map as $group) {
// Can't array_fill_keys() here because 'false' gets encoded wrong.
$groups[$group] = array();
}
foreach ($map as $key => $group) {
$groups[$group][$key] = $list[$key];
}
$args = func_get_args();
$args = array_slice($args, 2);
if ($args) {
array_unshift($args, null);
foreach ($groups as $group_key => $grouped) {
$args[0] = $grouped;
$groups[$group_key] = call_user_func_array('mgroup', $args);
}
}
return $groups;
}
/**
* Group a list of arrays by the value of some index. This function is the same
* as @{function:mgroup}, except it operates on the values of array indexes
* rather than the return values of method calls.
*
* @param list List of arrays to group by some index value.
* @param string Name of an index to select from each array in order to
* determine which group it should be placed into.
* @param ... Zero or more additional indexes names, to subgroup the
* groups.
* @return dict Dictionary mapping distinct index values to lists of
* all objects which had that value at the index.
*/
function igroup(array $list, $by /* , ... */) {
$map = ipull($list, $by);
$groups = array();
foreach ($map as $group) {
$groups[$group] = array();
}
foreach ($map as $key => $group) {
$groups[$group][$key] = $list[$key];
}
$args = func_get_args();
$args = array_slice($args, 2);
if ($args) {
array_unshift($args, null);
foreach ($groups as $group_key => $grouped) {
$args[0] = $grouped;
$groups[$group_key] = call_user_func_array('igroup', $args);
}
}
return $groups;
}
/**
* Sort a list of objects by the return value of some method. In PHP, this is
* often vastly more efficient than `usort()` and similar.
*
* // Sort a list of Duck objects by name.
* $sorted = msort($ducks, 'getName');
*
* It is usually significantly more efficient to define an ordering method
* on objects and call `msort()` than to write a comparator. It is often more
* convenient, as well.
*
* NOTE: This method does not take the list by reference; it returns a new list.
*
* @param list List of objects to sort by some property.
* @param string Name of a method to call on each object; the return values
* will be used to sort the list.
* @return list Objects ordered by the return values of the method calls.
*/
function msort(array $list, $method) {
$surrogate = mpull($list, $method);
asort($surrogate);
$result = array();
foreach ($surrogate as $key => $value) {
$result[$key] = $list[$key];
}
return $result;
}
/**
* Sort a list of objects by a sort vector.
*
* This sort is stable, well-behaved, and more efficient than `usort()`.
*
* @param list List of objects to sort.
* @param string Name of a method to call on each object. The method must
* return a @{class:PhutilSortVector}.
* @return list Objects ordered by the vectors.
*/
function msortv(array $list, $method) {
$surrogate = mpull($list, $method);
$index = 0;
foreach ($surrogate as $key => $value) {
if (!($value instanceof PhutilSortVector)) {
throw new Exception(
pht(
'Objects passed to "%s" must return sort vectors (objects of '.
'class "%s") from the specified method ("%s"). One object (with '.
'key "%s") did not.',
'msortv()',
'PhutilSortVector',
$method,
$key));
}
// Add the original index to keep the sort stable.
$value->addInt($index++);
$surrogate[$key] = (string)$value;
}
asort($surrogate, SORT_STRING);
$result = array();
foreach ($surrogate as $key => $value) {
$result[$key] = $list[$key];
}
return $result;
}
/**
* Sort a list of arrays by the value of some index. This method is identical to
* @{function:msort}, but operates on a list of arrays instead of a list of
* objects.
*
* @param list List of arrays to sort by some index value.
* @param string Index to access on each object; the return values
* will be used to sort the list.
* @return list Arrays ordered by the index values.
*/
function isort(array $list, $index) {
$surrogate = ipull($list, $index);
asort($surrogate);
$result = array();
foreach ($surrogate as $key => $value) {
$result[$key] = $list[$key];
}
return $result;
}
/**
* Filter a list of objects by executing a method across all the objects and
* filter out the ones with empty() results. this function works just like
* @{function:ifilter}, except that it operates on a list of objects instead
* of a list of arrays.
*
* For example, to remove all objects with no children from a list, where
* 'hasChildren' is a method name, do this:
*
* mfilter($list, 'hasChildren');
*
* The optional third parameter allows you to negate the operation and filter
* out nonempty objects. To remove all objects that DO have children, do this:
*
* mfilter($list, 'hasChildren', true);
*
* @param array List of objects to filter.
* @param string A method name.
* @param bool Optionally, pass true to drop objects which pass the
* filter instead of keeping them.
* @return array List of objects which pass the filter.
*/
function mfilter(array $list, $method, $negate = false) {
if (!is_string($method)) {
throw new InvalidArgumentException(pht('Argument method is not a string.'));
}
$result = array();
foreach ($list as $key => $object) {
$value = $object->$method();
if (!$negate) {
if (!empty($value)) {
$result[$key] = $object;
}
} else {
if (empty($value)) {
$result[$key] = $object;
}
}
}
return $result;
}
/**
* Filter a list of arrays by removing the ones with an empty() value for some
* index. This function works just like @{function:mfilter}, except that it
* operates on a list of arrays instead of a list of objects.
*
* For example, to remove all arrays without value for key 'username', do this:
*
* ifilter($list, 'username');
*
* The optional third parameter allows you to negate the operation and filter
* out nonempty arrays. To remove all arrays that DO have value for key
* 'username', do this:
*
* ifilter($list, 'username', true);
*
* @param array List of arrays to filter.
* @param scalar The index.
* @param bool Optionally, pass true to drop arrays which pass the
* filter instead of keeping them.
* @return array List of arrays which pass the filter.
*/
function ifilter(array $list, $index, $negate = false) {
if (!is_scalar($index)) {
throw new InvalidArgumentException(pht('Argument index is not a scalar.'));
}
$result = array();
if (!$negate) {
foreach ($list as $key => $array) {
if (!empty($array[$index])) {
$result[$key] = $array;
}
}
} else {
foreach ($list as $key => $array) {
if (empty($array[$index])) {
$result[$key] = $array;
}
}
}
return $result;
}
/**
* Selects a list of keys from an array, returning a new array with only the
* key-value pairs identified by the selected keys, in the specified order.
*
* Note that since this function orders keys in the result according to the
* order they appear in the list of keys, there are effectively two common
* uses: either reducing a large dictionary to a smaller one, or changing the
* key order on an existing dictionary.
*
* @param dict Dictionary of key-value pairs to select from.
* @param list List of keys to select.
* @return dict Dictionary of only those key-value pairs where the key was
* present in the list of keys to select. Ordering is
* determined by the list order.
*/
function array_select_keys(array $dict, array $keys) {
$result = array();
foreach ($keys as $key) {
if (array_key_exists($key, $dict)) {
$result[$key] = $dict[$key];
}
}
return $result;
}
/**
* Checks if all values of array are instances of the passed class. Throws
* `InvalidArgumentException` if it isn't true for any value.
*
* @param array
* @param string Name of the class or 'array' to check arrays.
* @return array Returns passed array.
*/
function assert_instances_of(array $arr, $class) {
$is_array = !strcasecmp($class, 'array');
foreach ($arr as $key => $object) {
if ($is_array) {
if (!is_array($object)) {
$given = gettype($object);
throw new InvalidArgumentException(
pht(
"Array item with key '%s' must be of type array, %s given.",
$key,
$given));
}
} else if (!($object instanceof $class)) {
$given = gettype($object);
if (is_object($object)) {
$given = pht('instance of %s', get_class($object));
}
throw new InvalidArgumentException(
pht(
"Array item with key '%s' must be an instance of %s, %s given.",
$key,
$class,
$given));
}
}
return $arr;
}
/**
* Assert that passed data can be converted to string.
*
* @param string Assert that this data is valid.
* @return void
*
* @task assert
*/
function assert_stringlike($parameter) {
switch (gettype($parameter)) {
case 'string':
case 'NULL':
case 'boolean':
case 'double':
case 'integer':
return;
case 'object':
if (method_exists($parameter, '__toString')) {
return;
}
break;
case 'array':
case 'resource':
case 'unknown type':
default:
break;
}
throw new InvalidArgumentException(
pht(
'Argument must be scalar or object which implements %s!',
'__toString()'));
}
/**
* Returns the first argument which is not strictly null, or `null` if there
* are no such arguments. Identical to the MySQL function of the same name.
*
* @param ... Zero or more arguments of any type.
* @return mixed First non-`null` arg, or null if no such arg exists.
*/
function coalesce(/* ... */) {
$args = func_get_args();
foreach ($args as $arg) {
if ($arg !== null) {
return $arg;
}
}
return null;
}
/**
* Similar to @{function:coalesce}, but less strict: returns the first
* non-`empty()` argument, instead of the first argument that is strictly
* non-`null`. If no argument is nonempty, it returns the last argument. This
* is useful idiomatically for setting defaults:
*
* $display_name = nonempty($user_name, $full_name, "Anonymous");
*
* @param ... Zero or more arguments of any type.
* @return mixed First non-`empty()` arg, or last arg if no such arg
* exists, or null if you passed in zero args.
*/
function nonempty(/* ... */) {
$args = func_get_args();
$result = null;
foreach ($args as $arg) {
$result = $arg;
if ($arg) {
break;
}
}
return $result;
}
/**
* Invokes the "new" operator with a vector of arguments. There is no way to
* `call_user_func_array()` on a class constructor, so you can instead use this
* function:
*
* $obj = newv($class_name, $argv);
*
* That is, these two statements are equivalent:
*
* $pancake = new Pancake('Blueberry', 'Maple Syrup', true);
* $pancake = newv('Pancake', array('Blueberry', 'Maple Syrup', true));
*
* DO NOT solve this problem in other, more creative ways! Three popular
* alternatives are:
*
* - Build a fake serialized object and unserialize it.
* - Invoke the constructor twice.
* - just use `eval()` lol
*
* These are really bad solutions to the problem because they can have side
* effects (e.g., __wakeup()) and give you an object in an otherwise impossible
* state. Please endeavor to keep your objects in possible states.
*
* If you own the classes you're doing this for, you should consider whether
* or not restructuring your code (for instance, by creating static
* construction methods) might make it cleaner before using `newv()`. Static
* constructors can be invoked with `call_user_func_array()`, and may give your
* class a cleaner and more descriptive API.
*
* @param string The name of a class.
* @param list Array of arguments to pass to its constructor.
* @return obj A new object of the specified class, constructed by passing
* the argument vector to its constructor.
*/
function newv($class_name, array $argv) {
$reflector = new ReflectionClass($class_name);
if ($argv) {
return $reflector->newInstanceArgs($argv);
} else {
return $reflector->newInstance();
}
}
/**
* Returns the first element of an array. Exactly like reset(), but doesn't
* choke if you pass it some non-referenceable value like the return value of
* a function.
*
* @param array Array to retrieve the first element from.
* @return wild The first value of the array.
*/
function head(array $arr) {
return reset($arr);
}
/**
* Returns the last element of an array. This is exactly like `end()` except
* that it won't warn you if you pass some non-referencable array to
* it -- e.g., the result of some other array operation.
*
* @param array Array to retrieve the last element from.
* @return wild The last value of the array.
*/
function last(array $arr) {
return end($arr);
}
/**
* Returns the first key of an array.
*
* @param array Array to retrieve the first key from.
* @return int|string The first key of the array.
*/
function head_key(array $arr) {
reset($arr);
return key($arr);
}
/**
* Returns the last key of an array.
*
* @param array Array to retrieve the last key from.
* @return int|string The last key of the array.
*/
function last_key(array $arr) {
end($arr);
return key($arr);
}
/**
* Merge a vector of arrays performantly. This has the same semantics as
* array_merge(), so these calls are equivalent:
*
* array_merge($a, $b, $c);
* array_mergev(array($a, $b, $c));
*
* However, when you have a vector of arrays, it is vastly more performant to
* merge them with this function than by calling array_merge() in a loop,
* because using a loop generates an intermediary array on each iteration.
*
* @param list Vector of arrays to merge.
* @return list Arrays, merged with array_merge() semantics.
*/
function array_mergev(array $arrayv) {
if (!$arrayv) {
return array();
}
foreach ($arrayv as $key => $item) {
if (!is_array($item)) {
throw new InvalidArgumentException(
pht(
'Expected all items passed to `%s` to be arrays, but '.
'argument with key "%s" has type "%s".',
__FUNCTION__.'()',
$key,
gettype($item)));
}
}
return call_user_func_array('array_merge', $arrayv);
}
/**
* Split a corpus of text into lines. This function splits on "\n", "\r\n", or
* a mixture of any of them.
*
* NOTE: This function does not treat "\r" on its own as a newline because none
* of SVN, Git or Mercurial do on any OS.
*
* @param string Block of text to be split into lines.
* @param bool If true, retain line endings in result strings.
* @return list List of lines.
*/
function phutil_split_lines($corpus, $retain_endings = true) {
if (!strlen($corpus)) {
return array('');
}
// Split on "\r\n" or "\n".
if ($retain_endings) {
$lines = preg_split('/(?<=\n)/', $corpus);
} else {
$lines = preg_split('/\r?\n/', $corpus);
}
// If the text ends with "\n" or similar, we'll end up with an empty string
// at the end; discard it.
if (end($lines) == '') {
array_pop($lines);
}
if ($corpus instanceof PhutilSafeHTML) {
return array_map('phutil_safe_html', $lines);
}
return $lines;
}
/**
* Simplifies a common use of `array_combine()`. Specifically, this:
*
* COUNTEREXAMPLE:
* if ($list) {
* $result = array_combine($list, $list);
* } else {
* // Prior to PHP 5.4, array_combine() failed if given empty arrays.
* $result = array();
* }
*
* ...is equivalent to this:
*
* $result = array_fuse($list);
*
* @param list List of scalars.
* @return dict Dictionary with inputs mapped to themselves.
*/
function array_fuse(array $list) {
if ($list) {
return array_combine($list, $list);
}
return array();
}
/**
* Add an element between every two elements of some array. That is, given a
* list `A, B, C, D`, and some element to interleave, `x`, this function returns
* `A, x, B, x, C, x, D`. This works like `implode()`, but does not concatenate
* the list into a string. In particular:
*
* implode('', array_interleave($x, $list));
*
* ...is equivalent to:
*
* implode($x, $list);
*
* This function does not preserve keys.
*
* @param wild Element to interleave.
* @param list List of elements to be interleaved.
* @return list Original list with the new element interleaved.
*/
function array_interleave($interleave, array $array) {
$result = array();
foreach ($array as $item) {
$result[] = $item;
$result[] = $interleave;
}
array_pop($result);
return $result;
}
function phutil_is_windows() {
// We can also use PHP_OS, but that's kind of sketchy because it returns
// "WINNT" for Windows 7 and "Darwin" for Mac OS X. Practically, testing for
// DIRECTORY_SEPARATOR is more straightforward.
return (DIRECTORY_SEPARATOR != '/');
}
function phutil_is_hiphop_runtime() {
return (array_key_exists('HPHP', $_ENV) && $_ENV['HPHP'] === 1);
}
/**
* Converts a string to a loggable one, with unprintables and newlines escaped.
*
* @param string Any string.
* @return string String with control and newline characters escaped, suitable
* for printing on a single log line.
*/
function phutil_loggable_string($string) {
if (preg_match('/^[\x20-\x7E]+$/', $string)) {
return $string;
}
$result = '';
static $c_map = array(
'\\' => '\\\\',
"\n" => '\\n',
"\r" => '\\r',
"\t" => '\\t',
);
$len = strlen($string);
for ($ii = 0; $ii < $len; $ii++) {
$c = $string[$ii];
if (isset($c_map[$c])) {
$result .= $c_map[$c];
} else {
$o = ord($c);
if ($o < 0x20 || $o == 0x7F) {
$result .= '\\x'.sprintf('%02X', $o);
} else {
$result .= $c;
}
}
}
return $result;
}
/**
* Perform an `fwrite()` which distinguishes between EAGAIN and EPIPE.
*
* PHP's `fwrite()` is broken, and never returns `false` for writes to broken
* nonblocking pipes: it always returns 0, and provides no straightforward
* mechanism for distinguishing between EAGAIN (buffer is full, can't write any
* more right now) and EPIPE or similar (no write will ever succeed).
*
* See: https://bugs.php.net/bug.php?id=39598
*
* If you call this method instead of `fwrite()`, it will attempt to detect
* when a zero-length write is caused by EAGAIN and return `0` only if the
* write really should be retried.
*
* @param resource Socket or pipe stream.
* @param string Bytes to write.
* @return bool|int Number of bytes written, or `false` on any error (including
* errors which `fwrite()` can not detect, like a broken pipe).
*/
function phutil_fwrite_nonblocking_stream($stream, $bytes) {
if (!strlen($bytes)) {
return 0;
}
$result = @fwrite($stream, $bytes);
if ($result !== 0) {
// In cases where some bytes are witten (`$result > 0`) or
// an error occurs (`$result === false`), the behavior of fwrite() is
// correct. We can return the value as-is.
return $result;
}
// If we make it here, we performed a 0-length write. Try to distinguish
// between EAGAIN and EPIPE. To do this, we're going to `stream_select()`
// the stream, write to it again if PHP claims that it's writable, and
// consider the pipe broken if the write fails.
$read = array();
$write = array($stream);
$except = array();
@stream_select($read, $write, $except, 0);
if (!$write) {
// The stream isn't writable, so we conclude that it probably really is
// blocked and the underlying error was EAGAIN. Return 0 to indicate that
// no data could be written yet.
return 0;
}
// If we make it here, PHP **just** claimed that this stream is writable, so
// perform a write. If the write also fails, conclude that these failures are
// EPIPE or some other permanent failure.
$result = @fwrite($stream, $bytes);
if ($result !== 0) {
// The write worked or failed explicitly. This value is fine to return.
return $result;
}
// We performed a 0-length write, were told that the stream was writable, and
// then immediately performed another 0-length write. Conclude that the pipe
// is broken and return `false`.
return false;
}
/**
* Convert a human-readable unit description into a numeric one. This function
* allows you to replace this:
*
* COUNTEREXAMPLE
* $ttl = (60 * 60 * 24 * 30); // 30 days
*
* ...with this:
*
* $ttl = phutil_units('30 days in seconds');
*
* ...which is self-documenting and difficult to make a mistake with.
*
* @param string Human readable description of a unit quantity.
* @return int Quantity of specified unit.
*/
function phutil_units($description) {
$matches = null;
if (!preg_match('/^(\d+) (\w+) in (\w+)$/', $description, $matches)) {
throw new InvalidArgumentException(
pht(
'Unable to parse unit specification (expected a specification in the '.
'form "%s"): %s',
'5 days in seconds',
$description));
}
$quantity = (int)$matches[1];
$src_unit = $matches[2];
$dst_unit = $matches[3];
$is_divisor = false;
switch ($dst_unit) {
case 'seconds':
switch ($src_unit) {
case 'second':
case 'seconds':
$factor = 1;
break;
case 'minute':
case 'minutes':
$factor = 60;
break;
case 'hour':
case 'hours':
$factor = 60 * 60;
break;
case 'day':
case 'days':
$factor = 60 * 60 * 24;
break;
default:
throw new InvalidArgumentException(
pht(
'This function can not convert from the unit "%s".',
$src_unit));
}
break;
case 'bytes':
switch ($src_unit) {
case 'byte':
case 'bytes':
$factor = 1;
break;
case 'bit':
case 'bits':
$factor = 8;
$is_divisor = true;
break;
default:
throw new InvalidArgumentException(
pht(
'This function can not convert from the unit "%s".',
$src_unit));
}
break;
default:
throw new InvalidArgumentException(
pht(
'This function can not convert into the unit "%s".',
$dst_unit));
}
if ($is_divisor) {
if ($quantity % $factor) {
throw new InvalidArgumentException(
pht(
'"%s" is not an exact quantity.',
$description));
}
return (int)($quantity / $factor);
} else {
return $quantity * $factor;
}
}
/**
* Compute the number of microseconds that have elapsed since an earlier
* timestamp (from `microtime(true)`).
*
* @param double Microsecond-precision timestamp, from `microtime(true)`.
* @return int Elapsed microseconds.
*/
function phutil_microseconds_since($timestamp) {
if (!is_float($timestamp)) {
throw new Exception(
pht(
'Argument to "phutil_microseconds_since(...)" should be a value '.
'returned from "microtime(true)".'));
}
$delta = (microtime(true) - $timestamp);
$delta = 1000000 * $delta;
$delta = (int)$delta;
return $delta;
}
/**
* Decode a JSON dictionary.
*
* @param string A string which ostensibly contains a JSON-encoded list or
* dictionary.
* @return mixed Decoded list/dictionary.
*/
function phutil_json_decode($string) {
$result = @json_decode($string, true);
if (!is_array($result)) {
// Failed to decode the JSON. Try to use @{class:PhutilJSONParser} instead.
// This will probably fail, but will throw a useful exception.
$parser = new PhutilJSONParser();
$result = $parser->parse($string);
}
return $result;
}
/**
* Encode a value in JSON, raising an exception if it can not be encoded.
*
* @param wild A value to encode.
* @return string JSON representation of the value.
*/
function phutil_json_encode($value) {
$result = @json_encode($value);
if ($result === false) {
$reason = phutil_validate_json($value);
if (function_exists('json_last_error')) {
$err = json_last_error();
if (function_exists('json_last_error_msg')) {
$msg = json_last_error_msg();
$extra = pht('#%d: %s', $err, $msg);
} else {
$extra = pht('#%d', $err);
}
} else {
$extra = null;
}
if ($extra) {
$message = pht(
'Failed to JSON encode value (%s): %s.',
$extra,
$reason);
} else {
$message = pht(
'Failed to JSON encode value: %s.',
$reason);
}
throw new Exception($message);
}
return $result;
}
/**
* Produce a human-readable explanation why a value can not be JSON-encoded.
*
* @param wild Value to validate.
* @param string Path within the object to provide context.
* @return string|null Explanation of why it can't be encoded, or null.
*/
function phutil_validate_json($value, $path = '') {
if ($value === null) {
return;
}
if ($value === true) {
return;
}
if ($value === false) {
return;
}
if (is_int($value)) {
return;
}
if (is_float($value)) {
return;
}
if (is_array($value)) {
foreach ($value as $key => $subvalue) {
if (strlen($path)) {
$full_key = $path.' > ';
} else {
$full_key = '';
}
if (!phutil_is_utf8($key)) {
$full_key = $full_key.phutil_utf8ize($key);
return pht(
'Dictionary key "%s" is not valid UTF8, and cannot be JSON encoded.',
$full_key);
}
$full_key .= $key;
$result = phutil_validate_json($subvalue, $full_key);
if ($result !== null) {
return $result;
}
}
}
if (is_string($value)) {
if (!phutil_is_utf8($value)) {
$display = substr($value, 0, 256);
$display = phutil_utf8ize($display);
if (!strlen($path)) {
return pht(
'String value is not valid UTF8, and can not be JSON encoded: %s',
$display);
} else {
return pht(
'Dictionary value at key "%s" is not valid UTF8, and cannot be '.
'JSON encoded: %s',
$path,
$display);
}
}
}
return;
}
/**
* Decode an INI string.
*
* @param string
* @return mixed
*/
function phutil_ini_decode($string) {
$results = null;
$trap = new PhutilErrorTrap();
try {
if (!function_exists('parse_ini_string')) {
throw new PhutilMethodNotImplementedException(
pht(
'%s is not compatible with your version of PHP (%s). This function '.
'is only supported on PHP versions newer than 5.3.0.',
__FUNCTION__,
phpversion()));
}
$results = @parse_ini_string($string, true, INI_SCANNER_RAW);
if ($results === false) {
throw new PhutilINIParserException(trim($trap->getErrorsAsString()));
}
foreach ($results as $section => $result) {
if (!is_array($result)) {
// We JSON decode the value in ordering to perform the following
// conversions:
//
// - `'true'` => `true`
// - `'false'` => `false`
// - `'123'` => `123`
// - `'1.234'` => `1.234`
//
$result = json_decode($result, true);
if ($result !== null && !is_array($result)) {
$results[$section] = $result;
}
continue;
}
foreach ($result as $key => $value) {
$value = json_decode($value, true);
if ($value !== null && !is_array($value)) {
$results[$section][$key] = $value;
}
}
}
} catch (Exception $ex) {
$trap->destroy();
throw $ex;
}
$trap->destroy();
return $results;
}
/**
* Attempt to censor any plaintext credentials from a string.
*
* The major use case here is to censor usernames and passwords from command
* output. For example, when `git fetch` fails, the output includes credentials
* for authenticated HTTP remotes.
*
* @param string Some block of text.
* @return string A similar block of text, but with credentials that could
* be identified censored.
*/
function phutil_censor_credentials($string) {
return preg_replace(',(?<=://)([^/@\s]+)(?=@|$),', '********', $string);
}
/**
* Returns a parsable string representation of a variable.
*
* This function is intended to behave similarly to PHP's `var_export` function,
* but the output is intended to follow our style conventions.
*
* @param wild The variable you want to export.
* @return string
*/
function phutil_var_export($var) {
// `var_export(null, true)` returns `"NULL"` (in uppercase).
if ($var === null) {
return 'null';
}
// PHP's `var_export` doesn't format arrays very nicely. In particular:
//
// - An empty array is split over two lines (`"array (\n)"`).
// - A space separates "array" and the first opening brace.
// - Non-associative arrays are returned as associative arrays with an
// integer key.
//
if (is_array($var)) {
if (count($var) === 0) {
return 'array()';
}
// Don't show keys for non-associative arrays.
$show_keys = (array_keys($var) !== range(0, count($var) - 1));
$output = array();
$output[] = 'array(';
foreach ($var as $key => $value) {
// Adjust the indentation of the value.
$value = str_replace("\n", "\n ", phutil_var_export($value));
$output[] = ' '.
($show_keys ? var_export($key, true).' => ' : '').
$value.',';
}
$output[] = ')';
return implode("\n", $output);
}
// Let PHP handle everything else.
return var_export($var, true);
}
/**
* An improved version of `fnmatch`.
*
* @param string A glob pattern.
* @param string A path.
* @return bool
*/
function phutil_fnmatch($glob, $path) {
// Modify the glob to allow `**/` to match files in the root directory.
$glob = preg_replace('@(?:(?<!\\\\)\\*){2}/@', '{,*/,**/}', $glob);
$escaping = false;
$in_curlies = 0;
$regex = '';
for ($i = 0; $i < strlen($glob); $i++) {
$char = $glob[$i];
$next_char = ($i < strlen($glob) - 1) ? $glob[$i + 1] : null;
$escape = array('$', '(', ')', '+', '.', '^', '|');
$mapping = array();
if ($escaping) {
$escape[] = '*';
$escape[] = '?';
$escape[] = '{';
} else {
$mapping['*'] = $next_char === '*' ? '.*' : '[^/]*';
$mapping['?'] = '[^/]';
$mapping['{'] = '(';
if ($in_curlies) {
$mapping[','] = '|';
$mapping['}'] = ')';
}
}
if (in_array($char, $escape)) {
$regex .= "\\{$char}";
} else if ($replacement = idx($mapping, $char)) {
$regex .= $replacement;
} else if ($char === '\\') {
if ($escaping) {
$regex .= '\\\\';
}
$escaping = !$escaping;
continue;
} else {
$regex .= $char;
}
if ($char === '{' && !$escaping) {
$in_curlies++;
} else if ($char === '}' && $in_curlies && !$escaping) {
$in_curlies--;
}
$escaping = false;
}
if ($in_curlies || $escaping) {
throw new InvalidArgumentException(pht('Invalid glob pattern.'));
}
$regex = '(\A'.$regex.'\z)';
return (bool)preg_match($regex, $path);
}
/**
* Compare two hashes for equality.
*
* This function defuses two attacks: timing attacks and type juggling attacks.
*
* In a timing attack, the attacker observes that strings which match the
* secret take slightly longer to fail to match because more characters are
* compared. By testing a large number of strings, they can learn the secret
* character by character. This defuses timing attacks by always doing the
* same amount of work.
*
* In a type juggling attack, an attacker takes advantage of PHP's type rules
* where `"0" == "0e12345"` for any exponent. A portion of of hexadecimal
* hashes match this pattern and are vulnerable. This defuses this attack by
* performing bytewise character-by-character comparison.
*
* It is questionable how practical these attacks are, but they are possible
* in theory and defusing them is straightforward.
*
* @param string First hash.
* @param string Second hash.
* @return bool True if hashes are identical.
*/
function phutil_hashes_are_identical($u, $v) {
if (!is_string($u)) {
throw new Exception(pht('First hash argument must be a string.'));
}
if (!is_string($v)) {
throw new Exception(pht('Second hash argument must be a string.'));
}
if (strlen($u) !== strlen($v)) {
return false;
}
$len = strlen($v);
$bits = 0;
for ($ii = 0; $ii < $len; $ii++) {
$bits |= (ord($u[$ii]) ^ ord($v[$ii]));
}
return ($bits === 0);
}
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