1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166

//! Dex `Field` and supporting structures
use scroll::{ctx, Pread, Uleb128};

use crate::{
    annotation::AnnotationSetItem,
    class::ClassId,
    encoded_item::{EncodedItem, EncodedItemArray},
    encoded_value::EncodedValue,
    error::Error,
    jtype::{Type, TypeId},
    string::{DexString, StringId},
    ulong, ushort, utils,
};
use getset::{CopyGetters, Getters};

bitflags! {
    /// Access flags of a Field.
    pub struct AccessFlags: ulong {
        const PUBLIC = 0x1;
        const PRIVATE = 0x2;
        const PROTECTED = 0x4;
        const STATIC = 0x8;
        const FINAL = 0x10;
        const VOLATILE = 0x40;
        const TRANSIENT = 0x80;
        const SYNTHETIC = 0x1000;
        const ENUM = 0x4000;
    }
}

/// Represents the field of a class
#[derive(Debug, Getters, CopyGetters)]
pub struct Field {
    /// Name of the field.
    #[get = "pub"]
    name: DexString,
    /// Type of the field.
    #[get = "pub"]
    jtype: Type,
    /// Class which this field belongs to.
    #[get_copy = "pub"]
    class: ClassId,
    /// Access flags for the field.
    #[get_copy = "pub"]
    access_flags: AccessFlags,
    /// Initial value of the field. Always `None` for non-static fields.
    /// If the value is `None`, it is not guaranteed that initial_value is `null`
    /// at runtime. The field might be initialized in `<clinit>` method.
    initial_value: Option<EncodedValue>,
    /// Annotations of the field.
    #[get = "pub"]
    annotations: AnnotationSetItem,
}

impl Field {
    /// Initial value of the field. Always `None` for non-static fields.
    /// If the value is `None`, it is not guaranteed that initial_value is `null`
    /// at runtime. The field might be initialized in `<clinit>` method.
    pub fn initial_value(&self) -> Option<&EncodedValue> {
        self.initial_value.as_ref()
    }

    gen_is_flag_set!(is_public, PUBLIC);
    gen_is_flag_set!(is_private, PRIVATE);
    gen_is_flag_set!(is_protected, PROTECTED);
    gen_is_flag_set!(is_static, STATIC);
    gen_is_flag_set!(is_final, FINAL);
    gen_is_flag_set!(is_volatile, VOLATILE);
    gen_is_flag_set!(is_transient, TRANSIENT);
    gen_is_flag_set!(is_synthetic, SYNTHETIC);
    gen_is_flag_set!(is_enum, ENUM);

    /// Returns the value of `dalvik.annotation.Signature`.
    pub fn signature(&self) -> super::Result<Option<String>> {
        utils::get_signature(self.annotations())
    }

    pub(crate) fn try_from_dex<S: AsRef<[u8]>>(
        dex: &super::Dex<S>,
        encoded_field: &EncodedField,
        initial_value: Option<EncodedValue>,
        annotations: AnnotationSetItem,
    ) -> super::Result<Self> {
        debug!(target: "field", "encoded field: {:?}", encoded_field);
        let field_item = dex.get_field_item(encoded_field.field_id)?;
        debug!(target: "field", "field id item: {:?}", field_item);
        Ok(Self {
            name: dex.get_string(field_item.name_idx)?,
            jtype: dex.get_type(TypeId::from(field_item.type_idx))?,
            class: ClassId::from(field_item.class_idx),
            access_flags: AccessFlags::from_bits(encoded_field.access_flags).ok_or_else(|| {
                Error::InvalidId(format!(
                    "Invalid access flags when loading field {}",
                    field_item.name_idx
                ))
            })?,
            initial_value,
            annotations,
        })
    }
}

/// List of `EncodedField`s
pub type EncodedFieldArray = EncodedItemArray<EncodedField>;

/// Defines a `Field`
/// [Android docs](https://source.android.com/devices/tech/dalvik/dex-format#field-id-item)
#[derive(Pread, Debug, Getters, PartialEq)]
#[get = "pub"]
pub struct FieldIdItem {
    /// Index into `TypeId`s list which contains the defining class's `Type`.
    class_idx: ushort,
    /// Index into `TypeId`s list which contains the `Type` of the field.
    type_idx: ushort,
    /// Index into `StringId`s list which contains the name of the field.
    name_idx: StringId,
}

impl FieldIdItem {
    pub(crate) fn try_from_dex<T: AsRef<[u8]>>(
        dex: &super::Dex<T>,
        offset: ulong,
    ) -> super::Result<Self> {
        let source = &dex.source;
        Ok(source.pread_with(offset as usize, dex.get_endian())?)
    }
}

/// Index into the `FieldId`s list.
pub type FieldId = ulong;

/// Contains a `FieldId` along with its access flags.
/// [Android docs](https://source.android.com/devices/tech/dalvik/dex-format#encoded-field-format)
#[derive(Debug, CopyGetters)]
#[get_copy = "pub"]
pub struct EncodedField {
    /// Index into the `FieldId`s list for the identity of this field represented as
    /// a difference from the index of previous element in the list.
    pub(crate) field_id: FieldId,
    /// Access flags for the field.
    access_flags: ulong,
}

impl EncodedItem for EncodedField {
    fn id(&self) -> ulong {
        self.field_id
    }
}

impl<'a> ctx::TryFromCtx<'a, ulong> for EncodedField {
    type Error = Error;
    type Size = usize;

    fn try_from_ctx(source: &'a [u8], prev_id: ulong) -> super::Result<(Self, Self::Size)> {
        let offset = &mut 0;
        let id = Uleb128::read(source, offset)?;
        let access_flags = Uleb128::read(source, offset)?;
        Ok((
            Self {
                field_id: prev_id + id,
                access_flags,
            },
            *offset,
        ))
    }
}