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LibCore: Parse classless symbolic notation

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Jean-Baptiste Boric 2022-01-21 19:32:35 +01:00 • committed by Andreas Kling
parent 736af8c7da
commit 12a6ec9292
1 changed files with 36 additions and 23 deletions
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59
Userland/Libraries/LibCore/FilePermissionsMask.cpp
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@ -13,7 +13,8 @@
namespace Core {
enum State {
Reference,
Classes,
Operation,
Mode
};
@ -48,47 +49,59 @@ ErrorOr<FilePermissionsMask> FilePermissionsMask::from_symbolic_notation(StringV
{
auto mask = FilePermissionsMask();
u8 state = State::Reference;
u8 state = State::Classes;
u8 classes = 0;
u8 operation = 0;
for (auto ch : string) {
switch (state) {
case State::Reference: {
case State::Classes: {
// one or more [ugoa] terminated by one operator [+-=]
if (ch == 'u')
if (ch == 'u') {
classes |= ClassFlag::User;
else if (ch == 'g')
state = State::Operation;
break;
} else if (ch == 'g') {
classes |= ClassFlag::Group;
else if (ch == 'o')
state = State::Operation;
break;
} else if (ch == 'o') {
classes |= ClassFlag::Other;
else if (ch == 'a')
state = State::Operation;
break;
} else if (ch == 'a') {
classes = ClassFlag::User | ClassFlag::Group | ClassFlag::Other;
else {
if (classes == 0)
return Error::from_string_literal("invalid access class: expected 'u', 'g', 'o' or 'a' "sv);
if (ch == '+')
operation = Operation::Add;
else if (ch == '-')
operation = Operation::Remove;
else if (ch == '=')
operation = Operation::Assign;
else
return Error::from_string_literal("invalid operation: expected '+', '-' or '='"sv);
state = State::Mode;
state = State::Operation;
break;
}
}
[[fallthrough]];
case State::Operation: {
if (ch == '+')
operation = Operation::Add;
else if (ch == '-')
operation = Operation::Remove;
else if (ch == '=')
operation = Operation::Assign;
else if (classes == 0)
return Error::from_string_literal("invalid access class: expected 'u', 'g', 'o' or 'a' "sv);
else
return Error::from_string_literal("invalid operation: expected '+', '-' or '='"sv);
// if an operation was specified without a class, assume all
if (classes == 0)
classes = ClassFlag::User | ClassFlag::Group | ClassFlag::Other;
state = State::Mode;
break;
}
case State::Mode: {
// one or more [rwx] terminated by a comma
// End of mode part, expect reference next
// End of mode part, expect class next
if (ch == ',') {
state = State::Reference;
state = State::Classes;
classes = operation = 0;
continue;
}