/root/bitcoin/src/script/descriptor.h

Source
// Copyright (c) 2018-present The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_SCRIPT_DESCRIPTOR_H
#define BITCOIN_SCRIPT_DESCRIPTOR_H

#include <outputtype.h>
#include <script/script.h>
#include <script/sign.h>
#include <script/signingprovider.h>

#include <optional>
#include <vector>

using ExtPubKeyMap = std::unordered_map<uint32_t, CExtPubKey>;

/** Cache for single descriptor's derived extended pubkeys */
class DescriptorCache {
private:
    /** Map key expression index -> map of (key derivation index -> xpub) */
    std::unordered_map<uint32_t, ExtPubKeyMap> m_derived_xpubs;
    /** Map key expression index -> parent xpub */
    ExtPubKeyMap m_parent_xpubs;
    /** Map key expression index -> last hardened xpub */
    ExtPubKeyMap m_last_hardened_xpubs;

public:
    /** Cache a parent xpub
     *
     * @param[in] key_exp_pos Position of the key expression within the descriptor
     * @param[in] xpub The CExtPubKey to cache
     */
    void CacheParentExtPubKey(uint32_t key_exp_pos, const CExtPubKey& xpub);
    /** Retrieve a cached parent xpub
     *
     * @param[in] key_exp_pos Position of the key expression within the descriptor
     * @param[out] xpub The CExtPubKey to get from cache
     */
    bool GetCachedParentExtPubKey(uint32_t key_exp_pos, CExtPubKey& xpub) const;
    /** Cache an xpub derived at an index
     *
     * @param[in] key_exp_pos Position of the key expression within the descriptor
     * @param[in] der_index Derivation index of the xpub
     * @param[in] xpub The CExtPubKey to cache
     */
    void CacheDerivedExtPubKey(uint32_t key_exp_pos, uint32_t der_index, const CExtPubKey& xpub);
    /** Retrieve a cached xpub derived at an index
     *
     * @param[in] key_exp_pos Position of the key expression within the descriptor
     * @param[in] der_index Derivation index of the xpub
     * @param[out] xpub The CExtPubKey to get from cache
     */
    bool GetCachedDerivedExtPubKey(uint32_t key_exp_pos, uint32_t der_index, CExtPubKey& xpub) const;
    /** Cache a last hardened xpub
     *
     * @param[in] key_exp_pos Position of the key expression within the descriptor
     * @param[in] xpub The CExtPubKey to cache
     */
    void CacheLastHardenedExtPubKey(uint32_t key_exp_pos, const CExtPubKey& xpub);
    /** Retrieve a cached last hardened xpub
     *
     * @param[in] key_exp_pos Position of the key expression within the descriptor
     * @param[out] xpub The CExtPubKey to get from cache
     */
    bool GetCachedLastHardenedExtPubKey(uint32_t key_exp_pos, CExtPubKey& xpub) const;

    /** Retrieve all cached parent xpubs */
    ExtPubKeyMap GetCachedParentExtPubKeys() const;
    /** Retrieve all cached derived xpubs */
    std::unordered_map<uint32_t, ExtPubKeyMap> GetCachedDerivedExtPubKeys() const;
    /** Retrieve all cached last hardened xpubs */
    ExtPubKeyMap GetCachedLastHardenedExtPubKeys() const;

    /** Combine another DescriptorCache into this one.
     * Returns a cache containing the items from the other cache unknown to current cache
     */
    DescriptorCache MergeAndDiff(const DescriptorCache& other);
};

/** \brief Interface for parsed descriptor objects.
 *
 * Descriptors are strings that describe a set of scriptPubKeys, together with
 * all information necessary to solve them. By combining all information into
 * one, they avoid the need to separately import keys and scripts.
 *
 * Descriptors may be ranged, which occurs when the public keys inside are
 * specified in the form of HD chains (xpubs).
 *
 * Descriptors always represent public information - public keys and scripts -
 * but in cases where private keys need to be conveyed along with a descriptor,
 * they can be included inside by changing public keys to private keys (WIF
 * format), and changing xpubs by xprvs.
 *
 * Reference documentation about the descriptor language can be found in
 * doc/descriptors.md.
 */
struct Descriptor {
    virtual ~Descriptor() = default;

    /** Whether the expansion of this descriptor depends on the position. */
    virtual bool IsRange() const = 0;

    /** Whether this descriptor has all information about signing ignoring lack of private keys.
     *  This is true for all descriptors except ones that use `raw` or `addr` constructions. */
    virtual bool IsSolvable() const = 0;

    /** Convert the descriptor back to a string, undoing parsing. */
    virtual std::string ToString(bool compat_format=false) const = 0;

    /** Whether this descriptor will return one scriptPubKey or multiple (aka is or is not combo) */
    virtual bool IsSingleType() const = 0;

    /** Whether the given provider has all private keys required by this descriptor.
     * @return `false` if the descriptor doesn't have any keys or subdescriptors,
     *         or if the provider does not have all private keys required by
     *         the descriptor.
     */
    virtual bool HavePrivateKeys(const SigningProvider& provider) const = 0;

    /** Convert the descriptor to a private string. This uses public keys if the relevant private keys are not in the SigningProvider.
     *  If none of the relevant private keys are available, the output string in the "out" parameter will not contain any private key information,
     *  and this function will return "false".
     *  @param[in] provider The SigningProvider to query for private keys.
     *  @param[out] out The resulting descriptor string, containing private keys if available.
     *  @returns true if at least one private key available.
     */
    virtual bool ToPrivateString(const SigningProvider& provider, std::string& out) const = 0;

    /** Convert the descriptor to a normalized string. Normalized descriptors have the xpub at the last hardened step. This fails if the provided provider does not have the private keys to derive that xpub. */
    virtual bool ToNormalizedString(const SigningProvider& provider, std::string& out, const DescriptorCache* cache = nullptr) const = 0;

    /** Expand a descriptor at a specified position.
     *
     * @param[in] pos The position at which to expand the descriptor. If IsRange() is false, this is ignored.
     * @param[in] provider The provider to query for private keys in case of hardened derivation.
     * @param[out] output_scripts The expanded scriptPubKeys.
     * @param[out] out Scripts and public keys necessary for solving the expanded scriptPubKeys (may be equal to `provider`).
     * @param[out] write_cache Cache data necessary to evaluate the descriptor at this point without access to private keys.
     */
    virtual bool Expand(int pos, const SigningProvider& provider, std::vector<CScript>& output_scripts, FlatSigningProvider& out, DescriptorCache* write_cache = nullptr) const = 0;

    /** Expand a descriptor at a specified position using cached expansion data.
     *
     * @param[in] pos The position at which to expand the descriptor. If IsRange() is false, this is ignored.
     * @param[in] read_cache Cached expansion data.
     * @param[out] output_scripts The expanded scriptPubKeys.
     * @param[out] out Scripts and public keys necessary for solving the expanded scriptPubKeys (may be equal to `provider`).
     */
    virtual bool ExpandFromCache(int pos, const DescriptorCache& read_cache, std::vector<CScript>& output_scripts, FlatSigningProvider& out) const = 0;

    /** Expand the private key for a descriptor at a specified position, if possible.
     *
     * @param[in] pos The position at which to expand the descriptor. If IsRange() is false, this is ignored.
     * @param[in] provider The provider to query for the private keys.
     * @param[out] out Any private keys available for the specified `pos`.
     */
    virtual void ExpandPrivate(int pos, const SigningProvider& provider, FlatSigningProvider& out) const = 0;

    /** @return The OutputType of the scriptPubKey(s) produced by this descriptor. Or nullopt if indeterminate (multiple or none) */
    virtual std::optional<OutputType> GetOutputType() const = 0;

    /** Get the size of the scriptPubKey for this descriptor. */
    virtual std::optional<int64_t> ScriptSize() const = 0;

    /** Get the maximum size of a satisfaction for this descriptor, in weight units.
     *
     * @param use_max_sig Whether to assume ECDSA signatures will have a high-r.
     */
    virtual std::optional<int64_t> MaxSatisfactionWeight(bool use_max_sig) const = 0;

    /** Get the maximum size number of stack elements for satisfying this descriptor. */
    virtual std::optional<int64_t> MaxSatisfactionElems() const = 0;

    /** Return all (extended) public keys for this descriptor, including any from subdescriptors.
     *
     * @param[out] pubkeys Any public keys
     * @param[out] ext_pubs Any extended public keys
     */
    virtual void GetPubKeys(std::set<CPubKey>& pubkeys, std::set<CExtPubKey>& ext_pubs) const = 0;

    /** Semantic/safety warnings (includes subdescriptors). */
    virtual std::vector<std::string> Warnings() const = 0;

    /** Get the maximum key expression index. Used only for tests */
    virtual uint32_t GetMaxKeyExpr() const = 0;

    /** Get the number of key expressions in this descriptor. Used only for tests */
    virtual size_t GetKeyCount() const = 0;
};

/** Parse a `descriptor` string. Included private keys are put in `out`.
 *
 * If the descriptor has a checksum, it must be valid. If `require_checksum`
 * is set, the checksum is mandatory - otherwise it is optional.
 *
 * If a parse error occurs, or the checksum is missing/invalid, or anything
 * else is wrong, an empty vector is returned.
 */
std::vector<std::unique_ptr<Descriptor>> Parse(std::string_view descriptor, FlatSigningProvider& out, std::string& error, bool require_checksum = false);

/** Get the checksum for a `descriptor`.
 *
 * - If it already has one, and it is correct, return the checksum in the input.
 * - If it already has one that is wrong, return "".
 * - If it does not already have one, return the checksum that would need to be added.
 */
std::string GetDescriptorChecksum(const std::string& descriptor);

/** Find a descriptor for the specified `script`, using information from `provider` where possible.
 *
 * A non-ranged descriptor which only generates the specified script will be returned in all
 * circumstances.
 *
 * For public keys with key origin information, this information will be preserved in the returned
 * descriptor.
 *
 * - If all information for solving `script` is present in `provider`, a descriptor will be returned
 *   which is IsSolvable() and encapsulates said information.
 * - Failing that, if `script` corresponds to a known address type, an "addr()" descriptor will be
 *   returned (which is not IsSolvable()).
 * - Failing that, a "raw()" descriptor is returned.
 */
std::unique_ptr<Descriptor> InferDescriptor(const CScript& script, const SigningProvider& provider);

/** Unique identifier that may not change over time, unless explicitly marked as not backwards compatible.
*   This is not part of BIP 380, not guaranteed to be interoperable and should not be exposed to the user.
*/
uint256 DescriptorID(const Descriptor& desc);

#endif // BITCOIN_SCRIPT_DESCRIPTOR_H

Bitcoin Core Fuzz Coverage Report

Coverage Report

Created: 2026-03-24 13:57

Line	Count	Source
1		// Copyright (c) 2018-present The Bitcoin Core developers
2		// Distributed under the MIT software license, see the accompanying
3		// file COPYING or http://www.opensource.org/licenses/mit-license.php.
4
5		#ifndef BITCOIN_SCRIPT_DESCRIPTOR_H
6		#define BITCOIN_SCRIPT_DESCRIPTOR_H
7
8		#include <outputtype.h>
9		#include <script/script.h>
10		#include <script/sign.h>
11		#include <script/signingprovider.h>
12
13		#include <optional>
14		#include <vector>
15
16		using ExtPubKeyMap = std::unordered_map<uint32_t, CExtPubKey>;
17
18		/** Cache for single descriptor's derived extended pubkeys */
19		class DescriptorCache {
20		private:
21		/** Map key expression index -> map of (key derivation index -> xpub) */
22		std::unordered_map<uint32_t, ExtPubKeyMap> m_derived_xpubs;
23		/** Map key expression index -> parent xpub */
24		ExtPubKeyMap m_parent_xpubs;
25		/** Map key expression index -> last hardened xpub */
26		ExtPubKeyMap m_last_hardened_xpubs;
27
28		public:
29		/** Cache a parent xpub
30		*
31		* @param[in] key_exp_pos Position of the key expression within the descriptor
32		* @param[in] xpub The CExtPubKey to cache
33		*/
34		void CacheParentExtPubKey(uint32_t key_exp_pos, const CExtPubKey& xpub);
35		/** Retrieve a cached parent xpub
36		*
37		* @param[in] key_exp_pos Position of the key expression within the descriptor
38		* @param[out] xpub The CExtPubKey to get from cache
39		*/
40		bool GetCachedParentExtPubKey(uint32_t key_exp_pos, CExtPubKey& xpub) const;
41		/** Cache an xpub derived at an index
42		*
43		* @param[in] key_exp_pos Position of the key expression within the descriptor
44		* @param[in] der_index Derivation index of the xpub
45		* @param[in] xpub The CExtPubKey to cache
46		*/
47		void CacheDerivedExtPubKey(uint32_t key_exp_pos, uint32_t der_index, const CExtPubKey& xpub);
48		/** Retrieve a cached xpub derived at an index
49		*
50		* @param[in] key_exp_pos Position of the key expression within the descriptor
51		* @param[in] der_index Derivation index of the xpub
52		* @param[out] xpub The CExtPubKey to get from cache
53		*/
54		bool GetCachedDerivedExtPubKey(uint32_t key_exp_pos, uint32_t der_index, CExtPubKey& xpub) const;
55		/** Cache a last hardened xpub
56		*
57		* @param[in] key_exp_pos Position of the key expression within the descriptor
58		* @param[in] xpub The CExtPubKey to cache
59		*/
60		void CacheLastHardenedExtPubKey(uint32_t key_exp_pos, const CExtPubKey& xpub);
61		/** Retrieve a cached last hardened xpub
62		*
63		* @param[in] key_exp_pos Position of the key expression within the descriptor
64		* @param[out] xpub The CExtPubKey to get from cache
65		*/
66		bool GetCachedLastHardenedExtPubKey(uint32_t key_exp_pos, CExtPubKey& xpub) const;
67
68		/** Retrieve all cached parent xpubs */
69		ExtPubKeyMap GetCachedParentExtPubKeys() const;
70		/** Retrieve all cached derived xpubs */
71		std::unordered_map<uint32_t, ExtPubKeyMap> GetCachedDerivedExtPubKeys() const;
72		/** Retrieve all cached last hardened xpubs */
73		ExtPubKeyMap GetCachedLastHardenedExtPubKeys() const;
74
75		/** Combine another DescriptorCache into this one.
76		* Returns a cache containing the items from the other cache unknown to current cache
77		*/
78		DescriptorCache MergeAndDiff(const DescriptorCache& other);
79		};
80
81		/** \brief Interface for parsed descriptor objects.
82		*
83		* Descriptors are strings that describe a set of scriptPubKeys, together with
84		* all information necessary to solve them. By combining all information into
85		* one, they avoid the need to separately import keys and scripts.
86		*
87		* Descriptors may be ranged, which occurs when the public keys inside are
88		* specified in the form of HD chains (xpubs).
89		*
90		* Descriptors always represent public information - public keys and scripts -
91		* but in cases where private keys need to be conveyed along with a descriptor,
92		* they can be included inside by changing public keys to private keys (WIF
93		* format), and changing xpubs by xprvs.
94		*
95		* Reference documentation about the descriptor language can be found in
96		* doc/descriptors.md.
97		*/
98		struct Descriptor {
99	0	virtual ~Descriptor() = default;
100
101		/** Whether the expansion of this descriptor depends on the position. */
102		virtual bool IsRange() const = 0;
103
104		/** Whether this descriptor has all information about signing ignoring lack of private keys.
105		* This is true for all descriptors except ones that use `raw` or `addr` constructions. */
106		virtual bool IsSolvable() const = 0;
107
108		/** Convert the descriptor back to a string, undoing parsing. */
109		virtual std::string ToString(bool compat_format=false) const = 0;
110
111		/** Whether this descriptor will return one scriptPubKey or multiple (aka is or is not combo) */
112		virtual bool IsSingleType() const = 0;
113
114		/** Whether the given provider has all private keys required by this descriptor.
115		* @return `false` if the descriptor doesn't have any keys or subdescriptors,
116		* or if the provider does not have all private keys required by
117		* the descriptor.
118		*/
119		virtual bool HavePrivateKeys(const SigningProvider& provider) const = 0;
120
121		/** Convert the descriptor to a private string. This uses public keys if the relevant private keys are not in the SigningProvider.
122		* If none of the relevant private keys are available, the output string in the "out" parameter will not contain any private key information,
123		* and this function will return "false".
124		* @param[in] provider The SigningProvider to query for private keys.
125		* @param[out] out The resulting descriptor string, containing private keys if available.
126		* @returns true if at least one private key available.
127		*/
128		virtual bool ToPrivateString(const SigningProvider& provider, std::string& out) const = 0;
129
130		/** Convert the descriptor to a normalized string. Normalized descriptors have the xpub at the last hardened step. This fails if the provided provider does not have the private keys to derive that xpub. */
131		virtual bool ToNormalizedString(const SigningProvider& provider, std::string& out, const DescriptorCache* cache = nullptr) const = 0;
132
133		/** Expand a descriptor at a specified position.
134		*
135		* @param[in] pos The position at which to expand the descriptor. If IsRange() is false, this is ignored.
136		* @param[in] provider The provider to query for private keys in case of hardened derivation.
137		* @param[out] output_scripts The expanded scriptPubKeys.
138		* @param[out] out Scripts and public keys necessary for solving the expanded scriptPubKeys (may be equal to `provider`).
139		* @param[out] write_cache Cache data necessary to evaluate the descriptor at this point without access to private keys.
140		*/
141		virtual bool Expand(int pos, const SigningProvider& provider, std::vector<CScript>& output_scripts, FlatSigningProvider& out, DescriptorCache* write_cache = nullptr) const = 0;
142
143		/** Expand a descriptor at a specified position using cached expansion data.
144		*
145		* @param[in] pos The position at which to expand the descriptor. If IsRange() is false, this is ignored.
146		* @param[in] read_cache Cached expansion data.
147		* @param[out] output_scripts The expanded scriptPubKeys.
148		* @param[out] out Scripts and public keys necessary for solving the expanded scriptPubKeys (may be equal to `provider`).
149		*/
150		virtual bool ExpandFromCache(int pos, const DescriptorCache& read_cache, std::vector<CScript>& output_scripts, FlatSigningProvider& out) const = 0;
151
152		/** Expand the private key for a descriptor at a specified position, if possible.
153		*
154		* @param[in] pos The position at which to expand the descriptor. If IsRange() is false, this is ignored.
155		* @param[in] provider The provider to query for the private keys.
156		* @param[out] out Any private keys available for the specified `pos`.
157		*/
158		virtual void ExpandPrivate(int pos, const SigningProvider& provider, FlatSigningProvider& out) const = 0;
159
160		/** @return The OutputType of the scriptPubKey(s) produced by this descriptor. Or nullopt if indeterminate (multiple or none) */
161		virtual std::optional<OutputType> GetOutputType() const = 0;
162
163		/** Get the size of the scriptPubKey for this descriptor. */
164		virtual std::optional<int64_t> ScriptSize() const = 0;
165
166		/** Get the maximum size of a satisfaction for this descriptor, in weight units.
167		*
168		* @param use_max_sig Whether to assume ECDSA signatures will have a high-r.
169		*/
170		virtual std::optional<int64_t> MaxSatisfactionWeight(bool use_max_sig) const = 0;
171
172		/** Get the maximum size number of stack elements for satisfying this descriptor. */
173		virtual std::optional<int64_t> MaxSatisfactionElems() const = 0;
174
175		/** Return all (extended) public keys for this descriptor, including any from subdescriptors.
176		*
177		* @param[out] pubkeys Any public keys
178		* @param[out] ext_pubs Any extended public keys
179		*/
180		virtual void GetPubKeys(std::set<CPubKey>& pubkeys, std::set<CExtPubKey>& ext_pubs) const = 0;
181
182		/** Semantic/safety warnings (includes subdescriptors). */
183		virtual std::vector<std::string> Warnings() const = 0;
184
185		/** Get the maximum key expression index. Used only for tests */
186		virtual uint32_t GetMaxKeyExpr() const = 0;
187
188		/** Get the number of key expressions in this descriptor. Used only for tests */
189		virtual size_t GetKeyCount() const = 0;
190		};
191
192		/** Parse a `descriptor` string. Included private keys are put in `out`.
193		*
194		* If the descriptor has a checksum, it must be valid. If `require_checksum`
195		* is set, the checksum is mandatory - otherwise it is optional.
196		*
197		* If a parse error occurs, or the checksum is missing/invalid, or anything
198		* else is wrong, an empty vector is returned.
199		*/
200		std::vector<std::unique_ptr<Descriptor>> Parse(std::string_view descriptor, FlatSigningProvider& out, std::string& error, bool require_checksum = false);
201
202		/** Get the checksum for a `descriptor`.
203		*
204		* - If it already has one, and it is correct, return the checksum in the input.
205		* - If it already has one that is wrong, return "".
206		* - If it does not already have one, return the checksum that would need to be added.
207		*/
208		std::string GetDescriptorChecksum(const std::string& descriptor);
209
210		/** Find a descriptor for the specified `script`, using information from `provider` where possible.
211		*
212		* A non-ranged descriptor which only generates the specified script will be returned in all
213		* circumstances.
214		*
215		* For public keys with key origin information, this information will be preserved in the returned
216		* descriptor.
217		*
218		* - If all information for solving `script` is present in `provider`, a descriptor will be returned
219		* which is IsSolvable() and encapsulates said information.
220		* - Failing that, if `script` corresponds to a known address type, an "addr()" descriptor will be
221		* returned (which is not IsSolvable()).
222		* - Failing that, a "raw()" descriptor is returned.
223		*/
224		std::unique_ptr<Descriptor> InferDescriptor(const CScript& script, const SigningProvider& provider);
225
226		/** Unique identifier that may not change over time, unless explicitly marked as not backwards compatible.
227		* This is not part of BIP 380, not guaranteed to be interoperable and should not be exposed to the user.
228		*/
229		uint256 DescriptorID(const Descriptor& desc);
230
231		#endif // BITCOIN_SCRIPT_DESCRIPTOR_H