/tmp/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 <pubkey.h>
#include <uint256.h>

#include <cstddef>
#include <cstdint>
#include <memory>
#include <optional>
#include <set>
#include <string>
#include <string_view>
#include <unordered_map>
#include <vector>

class CScript;
class SigningProvider;
struct FlatSigningProvider;

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 at most 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;

    /** Whether this descriptor produces any scripts with the Expand functions */
    virtual bool HasScripts() 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

Coverage Report

Created: 2026-05-30 09:47

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 <pubkey.h>
10		#include <uint256.h>
11
12		#include <cstddef>
13		#include <cstdint>
14		#include <memory>
15		#include <optional>
16		#include <set>
17		#include <string>
18		#include <string_view>
19		#include <unordered_map>
20		#include <vector>
21
22		class CScript;
23		class SigningProvider;
24		struct FlatSigningProvider;
25
26		using ExtPubKeyMap = std::unordered_map<uint32_t, CExtPubKey>;
27
28		/** Cache for single descriptor's derived extended pubkeys */
29		class DescriptorCache {
30		private:
31		/** Map key expression index -> map of (key derivation index -> xpub) */
32		std::unordered_map<uint32_t, ExtPubKeyMap> m_derived_xpubs;
33		/** Map key expression index -> parent xpub */
34		ExtPubKeyMap m_parent_xpubs;
35		/** Map key expression index -> last hardened xpub */
36		ExtPubKeyMap m_last_hardened_xpubs;
37
38		public:
39		/** Cache a parent xpub
40		*
41		* @param[in] key_exp_pos Position of the key expression within the descriptor
42		* @param[in] xpub The CExtPubKey to cache
43		*/
44		void CacheParentExtPubKey(uint32_t key_exp_pos, const CExtPubKey& xpub);
45		/** Retrieve a cached parent xpub
46		*
47		* @param[in] key_exp_pos Position of the key expression within the descriptor
48		* @param[out] xpub The CExtPubKey to get from cache
49		*/
50		bool GetCachedParentExtPubKey(uint32_t key_exp_pos, CExtPubKey& xpub) const;
51		/** Cache an xpub derived at an index
52		*
53		* @param[in] key_exp_pos Position of the key expression within the descriptor
54		* @param[in] der_index Derivation index of the xpub
55		* @param[in] xpub The CExtPubKey to cache
56		*/
57		void CacheDerivedExtPubKey(uint32_t key_exp_pos, uint32_t der_index, const CExtPubKey& xpub);
58		/** Retrieve a cached xpub derived at an index
59		*
60		* @param[in] key_exp_pos Position of the key expression within the descriptor
61		* @param[in] der_index Derivation index of the xpub
62		* @param[out] xpub The CExtPubKey to get from cache
63		*/
64		bool GetCachedDerivedExtPubKey(uint32_t key_exp_pos, uint32_t der_index, CExtPubKey& xpub) const;
65		/** Cache a last hardened xpub
66		*
67		* @param[in] key_exp_pos Position of the key expression within the descriptor
68		* @param[in] xpub The CExtPubKey to cache
69		*/
70		void CacheLastHardenedExtPubKey(uint32_t key_exp_pos, const CExtPubKey& xpub);
71		/** Retrieve a cached last hardened xpub
72		*
73		* @param[in] key_exp_pos Position of the key expression within the descriptor
74		* @param[out] xpub The CExtPubKey to get from cache
75		*/
76		bool GetCachedLastHardenedExtPubKey(uint32_t key_exp_pos, CExtPubKey& xpub) const;
77
78		/** Retrieve all cached parent xpubs */
79		ExtPubKeyMap GetCachedParentExtPubKeys() const;
80		/** Retrieve all cached derived xpubs */
81		std::unordered_map<uint32_t, ExtPubKeyMap> GetCachedDerivedExtPubKeys() const;
82		/** Retrieve all cached last hardened xpubs */
83		ExtPubKeyMap GetCachedLastHardenedExtPubKeys() const;
84
85		/** Combine another DescriptorCache into this one.
86		* Returns a cache containing the items from the other cache unknown to current cache
87		*/
88		DescriptorCache MergeAndDiff(const DescriptorCache& other);
89		};
90
91		/** \brief Interface for parsed descriptor objects.
92		*
93		* Descriptors are strings that describe a set of scriptPubKeys, together with
94		* all information necessary to solve them. By combining all information into
95		* one, they avoid the need to separately import keys and scripts.
96		*
97		* Descriptors may be ranged, which occurs when the public keys inside are
98		* specified in the form of HD chains (xpubs).
99		*
100		* Descriptors always represent public information - public keys and scripts -
101		* but in cases where private keys need to be conveyed along with a descriptor,
102		* they can be included inside by changing public keys to private keys (WIF
103		* format), and changing xpubs by xprvs.
104		*
105		* Reference documentation about the descriptor language can be found in
106		* doc/descriptors.md.
107		*/
108		struct Descriptor {
109	404k	virtual ~Descriptor() = default;
110
111		/** Whether the expansion of this descriptor depends on the position. */
112		virtual bool IsRange() const = 0;
113
114		/** Whether this descriptor has all information about signing ignoring lack of private keys.
115		* This is true for all descriptors except ones that use `raw` or `addr` constructions. */
116		virtual bool IsSolvable() const = 0;
117
118		/** Convert the descriptor back to a string, undoing parsing. */
119		virtual std::string ToString(bool compat_format=false) const = 0;
120
121		/** Whether this descriptor will return at most one scriptPubKey or multiple (aka is or is not combo) */
122		virtual bool IsSingleType() const = 0;
123
124		/** Whether the given provider has all private keys required by this descriptor.
125		* @return `false` if the descriptor doesn't have any keys or subdescriptors,
126		* or if the provider does not have all private keys required by
127		* the descriptor.
128		*/
129		virtual bool HavePrivateKeys(const SigningProvider& provider) const = 0;
130
131		/** Convert the descriptor to a private string. This uses public keys if the relevant private keys are not in the SigningProvider.
132		* If none of the relevant private keys are available, the output string in the "out" parameter will not contain any private key information,
133		* and this function will return "false".
134		* @param[in] provider The SigningProvider to query for private keys.
135		* @param[out] out The resulting descriptor string, containing private keys if available.
136		* @returns true if at least one private key available.
137		*/
138		virtual bool ToPrivateString(const SigningProvider& provider, std::string& out) const = 0;
139
140		/** 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. */
141		virtual bool ToNormalizedString(const SigningProvider& provider, std::string& out, const DescriptorCache* cache = nullptr) const = 0;
142
143		/** Expand a descriptor at a specified position.
144		*
145		* @param[in] pos The position at which to expand the descriptor. If IsRange() is false, this is ignored.
146		* @param[in] provider The provider to query for private keys in case of hardened derivation.
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		* @param[out] write_cache Cache data necessary to evaluate the descriptor at this point without access to private keys.
150		*/
151		virtual bool Expand(int pos, const SigningProvider& provider, std::vector<CScript>& output_scripts, FlatSigningProvider& out, DescriptorCache* write_cache = nullptr) const = 0;
152
153		/** Expand a descriptor at a specified position using cached expansion data.
154		*
155		* @param[in] pos The position at which to expand the descriptor. If IsRange() is false, this is ignored.
156		* @param[in] read_cache Cached expansion data.
157		* @param[out] output_scripts The expanded scriptPubKeys.
158		* @param[out] out Scripts and public keys necessary for solving the expanded scriptPubKeys (may be equal to `provider`).
159		*/
160		virtual bool ExpandFromCache(int pos, const DescriptorCache& read_cache, std::vector<CScript>& output_scripts, FlatSigningProvider& out) const = 0;
161
162		/** Expand the private key for a descriptor at a specified position, if possible.
163		*
164		* @param[in] pos The position at which to expand the descriptor. If IsRange() is false, this is ignored.
165		* @param[in] provider The provider to query for the private keys.
166		* @param[out] out Any private keys available for the specified `pos`.
167		*/
168		virtual void ExpandPrivate(int pos, const SigningProvider& provider, FlatSigningProvider& out) const = 0;
169
170		/** @return The OutputType of the scriptPubKey(s) produced by this descriptor. Or nullopt if indeterminate (multiple or none) */
171		virtual std::optional<OutputType> GetOutputType() const = 0;
172
173		/** Get the size of the scriptPubKey for this descriptor. */
174		virtual std::optional<int64_t> ScriptSize() const = 0;
175
176		/** Get the maximum size of a satisfaction for this descriptor, in weight units.
177		*
178		* @param use_max_sig Whether to assume ECDSA signatures will have a high-r.
179		*/
180		virtual std::optional<int64_t> MaxSatisfactionWeight(bool use_max_sig) const = 0;
181
182		/** Get the maximum size number of stack elements for satisfying this descriptor. */
183		virtual std::optional<int64_t> MaxSatisfactionElems() const = 0;
184
185		/** Return all (extended) public keys for this descriptor, including any from subdescriptors.
186		*
187		* @param[out] pubkeys Any public keys
188		* @param[out] ext_pubs Any extended public keys
189		*/
190		virtual void GetPubKeys(std::set<CPubKey>& pubkeys, std::set<CExtPubKey>& ext_pubs) const = 0;
191
192		/** Whether this descriptor produces any scripts with the Expand functions */
193		virtual bool HasScripts() const = 0;
194
195		/** Semantic/safety warnings (includes subdescriptors). */
196		virtual std::vector<std::string> Warnings() const = 0;
197
198		/** Get the maximum key expression index. Used only for tests */
199		virtual uint32_t GetMaxKeyExpr() const = 0;
200
201		/** Get the number of key expressions in this descriptor. Used only for tests */
202		virtual size_t GetKeyCount() const = 0;
203		};
204
205		/** Parse a `descriptor` string. Included private keys are put in `out`.
206		*
207		* If the descriptor has a checksum, it must be valid. If `require_checksum`
208		* is set, the checksum is mandatory - otherwise it is optional.
209		*
210		* If a parse error occurs, or the checksum is missing/invalid, or anything
211		* else is wrong, an empty vector is returned.
212		*/
213		std::vector<std::unique_ptr<Descriptor>> Parse(std::string_view descriptor, FlatSigningProvider& out, std::string& error, bool require_checksum = false);
214
215		/** Get the checksum for a `descriptor`.
216		*
217		* - If it already has one, and it is correct, return the checksum in the input.
218		* - If it already has one that is wrong, return "".
219		* - If it does not already have one, return the checksum that would need to be added.
220		*/
221		std::string GetDescriptorChecksum(const std::string& descriptor);
222
223		/** Find a descriptor for the specified `script`, using information from `provider` where possible.
224		*
225		* A non-ranged descriptor which only generates the specified script will be returned in all
226		* circumstances.
227		*
228		* For public keys with key origin information, this information will be preserved in the returned
229		* descriptor.
230		*
231		* - If all information for solving `script` is present in `provider`, a descriptor will be returned
232		* which is IsSolvable() and encapsulates said information.
233		* - Failing that, if `script` corresponds to a known address type, an "addr()" descriptor will be
234		* returned (which is not IsSolvable()).
235		* - Failing that, a "raw()" descriptor is returned.
236		*/
237		std::unique_ptr<Descriptor> InferDescriptor(const CScript& script, const SigningProvider& provider);
238
239		/** Unique identifier that may not change over time, unless explicitly marked as not backwards compatible.
240		* This is not part of BIP 380, not guaranteed to be interoperable and should not be exposed to the user.
241		*/
242		uint256 DescriptorID(const Descriptor& desc);
243
244		#endif // BITCOIN_SCRIPT_DESCRIPTOR_H