%global _empty_manifest_terminate_build 0 Name: python-trie Version: 2.1.0 Release: 1 Summary: Python implementation of the Ethereum Trie structure License: MIT URL: https://github.com/ethereum/py-trie Source0: https://mirrors.nju.edu.cn/pypi/web/packages/cf/aa/4e4af1a1ebf7438f25628e13d50715003e10d24f66c90630fda4a836b181/trie-2.1.0.tar.gz BuildArch: noarch Requires: python3-eth-hash Requires: python3-eth-utils Requires: python3-hexbytes Requires: python3-rlp Requires: python3-sortedcontainers Requires: python3-typing-extensions Requires: python3-bumpversion Requires: python3-wheel Requires: python3-twine Requires: python3-eth-hash Requires: python3-hypothesis Requires: python3-pycryptodome Requires: python3-pytest-xdist Requires: python3-tox Requires: python3-pytest Requires: python3-black Requires: python3-flake8 Requires: python3-isort Requires: python3-black Requires: python3-flake8 Requires: python3-isort Requires: python3-hypothesis Requires: python3-pycryptodome Requires: python3-pytest-xdist Requires: python3-tox Requires: python3-pytest %description # Python Implementation of the Ethereum Trie structure [![PyPI](https://img.shields.io/pypi/v/trie.svg)](https://pypi.org/project/trie/) ![PyPI - Python Version](https://img.shields.io/pypi/pyversions/trie.svg) > This library and repository was previously located at [pipermerriam/py-trie](https://github.com/pipermerriam/py-trie). It was transferred to the Ethereum foundation GitHub in > November 2017 and renamed to `py-trie`. ## Installation ```sh pip install trie ``` ## Development ```sh pip install -e .[dev] ``` ### Running the tests You can run the tests with: ```sh pytest tests ``` Or you can install `tox` to run the full test suite. ### Releasing Pandoc is required for transforming the markdown README to the proper format to render correctly on pypi. For Debian-like systems: ```sh apt install pandoc ``` Or on OSX: ```sh brew install pandoc ``` To release a new version: ```sh make release bump=$$VERSION_PART_TO_BUMP$$ ``` #### How to bumpversion The version format for this repo is `{major}.{minor}.{patch}` for stable, and `{major}.{minor}.{patch}-{stage}.{devnum}` for unstable (`stage` can be alpha or beta). To issue the next version in line, use bumpversion and specify which part to bump, like `bumpversion minor` or `bumpversion devnum`. If you are in a beta version, `bumpversion stage` will switch to a stable. To issue an unstable version when the current version is stable, specify the new version explicitly, like `bumpversion --new-version 4.0.0-alpha.1 devnum` ## Usage ```python >>> from trie import HexaryTrie >>> t = HexaryTrie(db={}) >>> t.root_hash b'V\xe8\x1f\x17\x1b\xccU\xa6\xff\x83E\xe6\x92\xc0\xf8n[H\xe0\x1b\x99l\xad\xc0\x01b/\xb5\xe3c\xb4!' >>> t.set(b'my-key', b'some-value') >>> t.get(b'my-key') b'some-value' >>> t.exists(b'another-key') False >>> t.set(b'another-key', b'another-value') >>> t.exists(b'another-key') True >>> t.delete(b'another-key') >>> t.exists(b'another-key') False ``` You can also use it like a dictionary. ```python >>> from trie import HexaryTrie >>> t = HexaryTrie(db={}) >>> t.root_hash b'V\xe8\x1f\x17\x1b\xccU\xa6\xff\x83E\xe6\x92\xc0\xf8n[H\xe0\x1b\x99l\xad\xc0\x01b/\xb5\xe3c\xb4!' >>> t[b'my-key'] = b'some-value' >>> t[b'my-key'] b'some-value' >>> b'another-key' in t False >>> t[b'another-key'] = b'another-value' >>> b'another-key' in t True >>> del t[b'another-key'] >>> b'another-key' in t False ``` ### Traversing (inspecting trie internals) ```python >>> from trie import HexaryTrie >>> t = HexaryTrie(db={}) >>> t.root_hash b'V\xe8\x1f\x17\x1b\xccU\xa6\xff\x83E\xe6\x92\xc0\xf8n[H\xe0\x1b\x99l\xad\xc0\x01b/\xb5\xe3c\xb4!' >>> t[b'my-key'] = b'some-value' >>> t[b'my-other-key'] = b'another-value' # Look at the root node: >>> root_node = t.traverse(()) >>> root_node HexaryTrieNode(sub_segments=((0x6, 0xd, 0x7, 0x9, 0x2, 0xd, 0x6),), value=b'', suffix=(), raw=[b'\x16\xd7\x92\xd6', b'\xb4q\xb8h\xec\x1c\xe1\xf4\\\x88\xda\xb4\xc1\xc2n\xbaw\xd0\x9c\xf1\xacV\xb4Dk\xa7\xe6\xd7qf\xc2\x82']) # the root node is an extension down, because the first 7 nibbles are the same between the two keys # Let's walk down to the child of that extension >>> prefix6d792d6 = t.traverse(root_node.sub_segments[0]) >>> prefix6d792d6 HexaryTrieNode(sub_segments=((0xb,), (0xf,)), value=b'', suffix=(), raw=[b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', [b' ey', b'some-value'], b'', b'', b'', [b' ther-key', b'another-value'], b'']) # A branch node separates the second nibbles of b'k' and b'o': 0xb and 0xf # Notice the position of the children in the 11th and 15th index # Another way to get there without loading the root node from the database is using traverse_from: >>> assert t.traverse_from(root_node, root_node.sub_segments[0]) == prefix6d792d6 # Embedded nodes can be traversed to the same way as nodes stored in the database: >>> t.traverse(root_node.sub_segments[0] + (0xb,)) HexaryTrieNode(sub_segments=(), value=b'some-value', suffix=(0x6, 0x5, 0x7, 0x9), raw=[b' ey', b'some-value']) # This leaf node includes the suffix (the rest of the key, in nibbles, that haven't been traversed, # just b'ey': 0x6579 ``` ### Walking a full trie To walk through the full trie (for example, to verify that all node bodies are present in the database), use HexaryTrieFog and the traversal API above. For example: ```python >>> from trie import HexaryTrie >>> t = HexaryTrie(db={}) >>> t.root_hash b'V\xe8\x1f\x17\x1b\xccU\xa6\xff\x83E\xe6\x92\xc0\xf8n[H\xe0\x1b\x99l\xad\xc0\x01b/\xb5\xe3c\xb4!' >>> t[b'my-key'] = b'some-value' >>> t[b'my-other-key'] = b'another-value' >>> t[b'your-key'] = b'your-value' >>> t[b'your-other-key'] = b'your-other-value' >>> t.root_hash b'\xf8\xdd\xe4\x0f\xaa\xf4P7\xfa$\xfde>\xec\xb4i\x00N\xa3)\xcf\xef\x80\xc4YU\xe8\xe7\xbf\xa89\xd5' # Initialize a fog object to track unexplored prefixes in a trie walk >>> from from trie.fog import HexaryTrieFog >>> empty_fog = HexaryTrieFog() # At the beginning, the unexplored prefix is (), which means that none of the trie has been explored >>> prefix = empty_fog.nearest_unknown() () # So we start by exploring the node at prefix () -- which is the root node: >>> node = t.traverse(prefix) HexaryTrieNode(sub_segments=((0x6,), (0x7,)), value=b'', suffix=(), raw=[b'', b'', b'', b'', b'', b'', b"\x03\xd2vk\x85\xce\xe1\xa8\xdb'F\x8c\xe5\x15\xc6\n+M:th\xa1\\\xb13\xcc\xe8\xd0\x1d\xa7\xa8U", b"\x1b\x8d'\xb3\x99(yX\xaa\x96C!\xba'X \xbb|\xa6,\xb5V!\xd3\x1a\x05\xe5\xbf\x02\xa3fR", b'', b'', b'', b'', b'', b'', b'', b'', b'']) # and mark the root as explored, while defining the unexplored children: >>> level1fog = empty_fog.explore(prefix, node.sub_segments) # Now the unexplored prefixes are the keys starting with the four bits 6 and the four bits 7. # All other keys are known to not exist (and so have been explored) >>> level1fog HexaryTrieFog # So we continue exploring. The fog helps choose which prefix to explore next: >>> level1fog.nearest_unknown() (0x6,) # We can also look for the nearest unknown key to a particular target >>> prefix = level1fog.nearest_unknown((8, 1)) (0x7,) >>> node7 = node.traverse(prefix) HexaryTrieNode(sub_segments=((0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6),), value=b'', suffix=(), raw=[b'\x00\x96\xf7W"\xd6', b"\xe2\xe2oN\xe1\xf8\xda\xc1\x8c\x03\x92'\x93\x805\xad-\xef\x07_\x0ePV\x1f\xb5/lVZ\xc6\xc1\xf9"]) # We found an extension node, and mark it in the fog # For simpliticy, we'll start clobbering the `fog` variable >>> fog = level1fog.explore(prefix, node7.sub_segments) HexaryTrieFog # Let's explore the next branch node and see what's left >>> prefix = fog.nearest_unknown((7,)) (0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6) >>> node796f75722d6 = t.traverse(prefix) HexaryTrieNode(sub_segments=((0xb,), (0xf,)), value=b'', suffix=(), raw=[b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', [b' ey', b'your-value'], b'', b'', b'', [b' ther-key', b'your-other-value'], b'']) # Notice that the branch node inlines the values, but the fog and annotated node ignore them for now >>> fog = fog.explore(prefix, node796f75722d6.sub_segments) HexaryTrieFog # Index keys may not matter for some use cases, so we can leave them out # entirely, like nearest_unknown(). # There's one more feature to consider: we can look directionally to the right # of an index for the nearest prefix. >>> prefix = fog.nearest_right((0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xc)) (0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xf) # That same index key would give a closer prefix to the left if direction didn't matter # (See the difference in the very last nibble) >>> fog.nearest_unknown((0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xc)) (0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb) # So we traverse to this last embedded leaf node at `prefix` >>> a_leaf_node = t.traverse(prefix) HexaryTrieNode(sub_segments=(), value=b'your-other-value', suffix=(0x7, 0x4, 0x6, 0x8, 0x6, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb, 0x6, 0x5, 0x7, 0x9), raw=[b' ther-key', b'your-other-value']) # we mark the prefix as fully explored like so: >>> fog = fog.explore(prefix, a_leaf_node.sub_segments) HexaryTrieFog # Notice that sub_segments was empty, and the prefix has disappeared from our list of unexplored prefixes # So far we have dealt with an un-changing trie, but what if it is # modified while we are working on it? >>> del t[b'your-other-key'] >>> t[b'your-key-rebranched'] = b'your-value' >>> t.root_hash b'"\xc0\xcaQ\xa7X\x08E\xb5"A\xde\xbfY\xeb"XY\xb1O\x034=\x04\x06\xa9li\xd8\x92\xadP' # The unexplored prefixes we have before might not exist anymore. They might: # 1. have been deleted entirely, in which case, we will get a blank node, and need no special treatment # 2. lead us into the middle of a leaf or extension node, which makes things tricky >>> prefix = fog.nearest_unknown((8,)) (0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb) >>> t.traverse(prefix) TraversedPartialPath: Could not traverse through HexaryTrieNode(sub_segments=((0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb, 0x6, 0x5, 0x7, 0x9),), value=b'', suffix=(), raw=[b'\x19our-key', b'f\xbe\x88\x8f#\xd5\x15-8\xc0\x1f\xfb\xf7\x8b=\x98\x86 \xec\xdeK\x07\xc8\xbf\xa7\x93\xfa\x9e\xc1\x89@\x00']) at (0x7,), only partially traversed with: (0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb) # Let's drill into what this means: # - We fully traversed to a node at prefix (7,) # - We tried to traverse into the rest of the prefix # - We only got part-way through the extension node: (0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb) # - The extension node full sub-segment is actually: (0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb, 0x6, 0x5, 0x7, 0x9) # So what do we do about it? Catch the exception, and explore with the fog slightly differently >>> from trie.exceptions import TraversedPartialPath >>> last_exception = None >>> try: t.traverse(prefix) except TraversedPartialPath as exc: last_exception = exc # We can now continue exploring the children of the extension node, by using an attribute on the exception: >>> sub_segments = last_exception.simulated_node.sub_segments ((0x6, 0x5, 0x7, 0x9),) # Note that this sub-segment now carries us the rest of the way to the child # of the node that we only partially traversed into. # This "simulated_node" is created by slicing the extension node in two: the # first extension node having the path that we (partially) traversed, and the second # extension node being the child of that parent, which continues on to point to # the child of the original extension. # If the exception is raised on a leaf node, then the leaf node is sliced into # an extension and another shorter leaf node. >>> fog = fog.explore(prefix, sub_segments) HexaryTrieFog # So now we can pick up where we left off, traversing to the child of the extension node, and so on. >>> prefix = fog.nearest_unknown((8,)) (0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb, 0x6, 0x5, 0x7, 0x9) # The following will not raise a TraversedPartialPath exception, because we know that # a node was at the path, and the trie hasn't changed: >>> t.traverse(prefix) HexaryTrieNode(sub_segments=((0x2,),), value=b'your-value', suffix=(), raw=[b'', b'', [b'=rebranched', b'your-value'], b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'your-value']) # etc... ``` **Note**: `traverse()` will access the database for every node from the root to the target node. If navigating a large trie, consider using `TrieFrontierCache` and `HexaryTrie.traverse_from()` to minimize database lookups. See the tests in `tests/test_hexary_trie_walk.py` for some examples. ## BinaryTrie **Note:** One drawback of Binary Trie is that **one key can not be the prefix of another key**. For example, if you already set the value `value1` with key `key1`, you can not set another value with key `key` or `key11` and the like. ### BinaryTrie branch and witness helper functions ```python >>> from trie import BinaryTrie >>> from trie.branches import ( >>> check_if_branch_exist, >>> get_branch, >>> if_branch_valid, >>> get_witness_for_key_prefix, >>> ) >>> t = BinaryTrie(db={}) >>> t.root_hash b"\xc5\xd2F\x01\x86\xf7#<\x92~}\xb2\xdc\xc7\x03\xc0\xe5\x00\xb6S\xca\x82';{\xfa\xd8\x04]\x85\xa4p" >>> t.set(b'key1', b'value1') >>> t.set(b'key2', b'value2') ``` Now Trie looks like this: ``` root ---> (kvnode, *common key prefix*) | | | (branchnode) / \ / \ / \ (kvnode, *remain kepath*)(kvnode, *remain kepath*) | | | | | | (leafnode, b'value1') (leafnode, b'value2') ``` ```python >>> # check_if_branch_exist function >>> check_if_branch_exist(t.db, t.root_hash, b'key') True >>> check_if_branch_exist(t.db, t.root_hash, b'key1') True >>> check_if_branch_exist(t.db, t.root_hash, b'ken') False >>> check_if_branch_exist(t.db, t.root_hash, b'key123') False >>> # get_branch function >>> get_branch(t.db, t.root_hash, b'key1') (b'\x00\x82\x1a\xd9^L|38J\xed\xf31S\xb2\x97A\x8dy\x91RJ\x92\xf5ZC\xb4\x99T&;!\x9f\xa9!\xa2\xfe;', b"\x01*\xaccxH\x89\x08}\x93|\xda\xb9\r\x9b\x82\x8b\xb2Y\xbc\x10\xb9\x88\xf40\xef\xed\x8b'\x13\xbc\xa5\xccYGb\xc2\x8db\x88lPs@)\x86v\xd7B\xf7\xd3X\x93\xc9\xf0\xfd\xae\xe0`j#\x0b\xca;\xf8", b'\x00\x11\x8aEL3\x839E\xbd\xc4G\xd1xj\x0fxWu\xcb\xf6\xf3\xf2\x8e7!M\xca\x1c/\xd7\x7f\xed\xc6', b'\x02value1') ``` Node started with `b'\x00'`, `b'\x01'` and `b'\x02'` are kvnode, branchnode and leafnode respectively. ```python >>> get_branch(t.db, t.root_hash, b'key') (b'\x00\x82\x1a\xd9^L|38J\xed\xf31S\xb2\x97A\x8dy\x91RJ\x92\xf5ZC\xb4\x99T&;!\x9f\xa9!\xa2\xfe;',) >>> get_branch(t.db, t.root_hash, b'key123') # InvalidKeyError >>> get_branch(t.db, t.root_hash, b'key5') # there is still branch for non-exist key (b'\x00\x82\x1a\xd9^L|38J\xed\xf31S\xb2\x97A\x8dy\x91RJ\x92\xf5ZC\xb4\x99T&;!\x9f\xa9!\xa2\xfe;',) >>> # if_branch_valid function >>> v = t.get(b'key1') >>> b = get_branch(t.db, t.root_hash, b'key1') >>> if_branch_valid(b, t.root_hash, b'key1', v) True >>> v = t.get(b'key5') # v should be None >>> b = get_branch(t.db, t.root_hash, b'key5') >>> if_branch_valid(b, t.root_hash, b'key5', v) True >>> v = t.get(b'key1') >>> b = get_branch(t.db, t.root_hash, b'key2') >>> if_branch_valid(b, t.root_hash, b'key1', v) # KeyError >>> if_branch_valid([], t.root_hash, b'key1', v) # AssertionError >>> # get_witness_for_key_prefix function >>> get_witness_for_key_prefix(t.db, t.root_hash, b'key1') # equivalent to `get_branch(t.db, t.root_hash, b'key1')` (b'\x00\x82\x1a\xd9^L|38J\xed\xf31S\xb2\x97A\x8dy\x91RJ\x92\xf5ZC\xb4\x99T&;!\x9f\xa9!\xa2\xfe;', b"\x01*\xaccxH\x89\x08}\x93|\xda\xb9\r\x9b\x82\x8b\xb2Y\xbc\x10\xb9\x88\xf40\xef\xed\x8b'\x13\xbc\xa5\xccYGb\xc2\x8db\x88lPs@)\x86v\xd7B\xf7\xd3X\x93\xc9\xf0\xfd\xae\xe0`j#\x0b\xca;\xf8", b'\x00\x11\x8aEL3\x839E\xbd\xc4G\xd1xj\x0fxWu\xcb\xf6\xf3\xf2\x8e7!M\xca\x1c/\xd7\x7f\xed\xc6', b'\x02value1') >>> get_witness_for_key_prefix(t.db, t.root_hash, b'key') # this will include additional nodes of b'key2' (b'\x00\x82\x1a\xd9^L|38J\xed\xf31S\xb2\x97A\x8dy\x91RJ\x92\xf5ZC\xb4\x99T&;!\x9f\xa9!\xa2\xfe;', b"\x01*\xaccxH\x89\x08}\x93|\xda\xb9\r\x9b\x82\x8b\xb2Y\xbc\x10\xb9\x88\xf40\xef\xed\x8b'\x13\xbc\xa5\xccYGb\xc2\x8db\x88lPs@)\x86v\xd7B\xf7\xd3X\x93\xc9\xf0\xfd\xae\xe0`j#\x0b\xca;\xf8", b'\x00\x11\x8aEL3\x839E\xbd\xc4G\xd1xj\x0fxWu\xcb\xf6\xf3\xf2\x8e7!M\xca\x1c/\xd7\x7f\xed\xc6', b'\x02value1', b'\x00\x10O\xa9\x0b\x1c!_`<\xb5^\x98D\x89\x17\x148\xac\xda&\xb3P\xf6\x06[\x1b9\xc09\xbas\x85\xf5', b'\x02value2') >>> get_witness_for_key_prefix(t.db, t.root_hash, b'') # this will return the whole trie ``` %package -n python3-trie Summary: Python implementation of the Ethereum Trie structure Provides: python-trie BuildRequires: python3-devel BuildRequires: python3-setuptools BuildRequires: python3-pip %description -n python3-trie # Python Implementation of the Ethereum Trie structure [![PyPI](https://img.shields.io/pypi/v/trie.svg)](https://pypi.org/project/trie/) ![PyPI - Python Version](https://img.shields.io/pypi/pyversions/trie.svg) > This library and repository was previously located at [pipermerriam/py-trie](https://github.com/pipermerriam/py-trie). It was transferred to the Ethereum foundation GitHub in > November 2017 and renamed to `py-trie`. ## Installation ```sh pip install trie ``` ## Development ```sh pip install -e .[dev] ``` ### Running the tests You can run the tests with: ```sh pytest tests ``` Or you can install `tox` to run the full test suite. ### Releasing Pandoc is required for transforming the markdown README to the proper format to render correctly on pypi. For Debian-like systems: ```sh apt install pandoc ``` Or on OSX: ```sh brew install pandoc ``` To release a new version: ```sh make release bump=$$VERSION_PART_TO_BUMP$$ ``` #### How to bumpversion The version format for this repo is `{major}.{minor}.{patch}` for stable, and `{major}.{minor}.{patch}-{stage}.{devnum}` for unstable (`stage` can be alpha or beta). To issue the next version in line, use bumpversion and specify which part to bump, like `bumpversion minor` or `bumpversion devnum`. If you are in a beta version, `bumpversion stage` will switch to a stable. To issue an unstable version when the current version is stable, specify the new version explicitly, like `bumpversion --new-version 4.0.0-alpha.1 devnum` ## Usage ```python >>> from trie import HexaryTrie >>> t = HexaryTrie(db={}) >>> t.root_hash b'V\xe8\x1f\x17\x1b\xccU\xa6\xff\x83E\xe6\x92\xc0\xf8n[H\xe0\x1b\x99l\xad\xc0\x01b/\xb5\xe3c\xb4!' >>> t.set(b'my-key', b'some-value') >>> t.get(b'my-key') b'some-value' >>> t.exists(b'another-key') False >>> t.set(b'another-key', b'another-value') >>> t.exists(b'another-key') True >>> t.delete(b'another-key') >>> t.exists(b'another-key') False ``` You can also use it like a dictionary. ```python >>> from trie import HexaryTrie >>> t = HexaryTrie(db={}) >>> t.root_hash b'V\xe8\x1f\x17\x1b\xccU\xa6\xff\x83E\xe6\x92\xc0\xf8n[H\xe0\x1b\x99l\xad\xc0\x01b/\xb5\xe3c\xb4!' >>> t[b'my-key'] = b'some-value' >>> t[b'my-key'] b'some-value' >>> b'another-key' in t False >>> t[b'another-key'] = b'another-value' >>> b'another-key' in t True >>> del t[b'another-key'] >>> b'another-key' in t False ``` ### Traversing (inspecting trie internals) ```python >>> from trie import HexaryTrie >>> t = HexaryTrie(db={}) >>> t.root_hash b'V\xe8\x1f\x17\x1b\xccU\xa6\xff\x83E\xe6\x92\xc0\xf8n[H\xe0\x1b\x99l\xad\xc0\x01b/\xb5\xe3c\xb4!' >>> t[b'my-key'] = b'some-value' >>> t[b'my-other-key'] = b'another-value' # Look at the root node: >>> root_node = t.traverse(()) >>> root_node HexaryTrieNode(sub_segments=((0x6, 0xd, 0x7, 0x9, 0x2, 0xd, 0x6),), value=b'', suffix=(), raw=[b'\x16\xd7\x92\xd6', b'\xb4q\xb8h\xec\x1c\xe1\xf4\\\x88\xda\xb4\xc1\xc2n\xbaw\xd0\x9c\xf1\xacV\xb4Dk\xa7\xe6\xd7qf\xc2\x82']) # the root node is an extension down, because the first 7 nibbles are the same between the two keys # Let's walk down to the child of that extension >>> prefix6d792d6 = t.traverse(root_node.sub_segments[0]) >>> prefix6d792d6 HexaryTrieNode(sub_segments=((0xb,), (0xf,)), value=b'', suffix=(), raw=[b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', [b' ey', b'some-value'], b'', b'', b'', [b' ther-key', b'another-value'], b'']) # A branch node separates the second nibbles of b'k' and b'o': 0xb and 0xf # Notice the position of the children in the 11th and 15th index # Another way to get there without loading the root node from the database is using traverse_from: >>> assert t.traverse_from(root_node, root_node.sub_segments[0]) == prefix6d792d6 # Embedded nodes can be traversed to the same way as nodes stored in the database: >>> t.traverse(root_node.sub_segments[0] + (0xb,)) HexaryTrieNode(sub_segments=(), value=b'some-value', suffix=(0x6, 0x5, 0x7, 0x9), raw=[b' ey', b'some-value']) # This leaf node includes the suffix (the rest of the key, in nibbles, that haven't been traversed, # just b'ey': 0x6579 ``` ### Walking a full trie To walk through the full trie (for example, to verify that all node bodies are present in the database), use HexaryTrieFog and the traversal API above. For example: ```python >>> from trie import HexaryTrie >>> t = HexaryTrie(db={}) >>> t.root_hash b'V\xe8\x1f\x17\x1b\xccU\xa6\xff\x83E\xe6\x92\xc0\xf8n[H\xe0\x1b\x99l\xad\xc0\x01b/\xb5\xe3c\xb4!' >>> t[b'my-key'] = b'some-value' >>> t[b'my-other-key'] = b'another-value' >>> t[b'your-key'] = b'your-value' >>> t[b'your-other-key'] = b'your-other-value' >>> t.root_hash b'\xf8\xdd\xe4\x0f\xaa\xf4P7\xfa$\xfde>\xec\xb4i\x00N\xa3)\xcf\xef\x80\xc4YU\xe8\xe7\xbf\xa89\xd5' # Initialize a fog object to track unexplored prefixes in a trie walk >>> from from trie.fog import HexaryTrieFog >>> empty_fog = HexaryTrieFog() # At the beginning, the unexplored prefix is (), which means that none of the trie has been explored >>> prefix = empty_fog.nearest_unknown() () # So we start by exploring the node at prefix () -- which is the root node: >>> node = t.traverse(prefix) HexaryTrieNode(sub_segments=((0x6,), (0x7,)), value=b'', suffix=(), raw=[b'', b'', b'', b'', b'', b'', b"\x03\xd2vk\x85\xce\xe1\xa8\xdb'F\x8c\xe5\x15\xc6\n+M:th\xa1\\\xb13\xcc\xe8\xd0\x1d\xa7\xa8U", b"\x1b\x8d'\xb3\x99(yX\xaa\x96C!\xba'X \xbb|\xa6,\xb5V!\xd3\x1a\x05\xe5\xbf\x02\xa3fR", b'', b'', b'', b'', b'', b'', b'', b'', b'']) # and mark the root as explored, while defining the unexplored children: >>> level1fog = empty_fog.explore(prefix, node.sub_segments) # Now the unexplored prefixes are the keys starting with the four bits 6 and the four bits 7. # All other keys are known to not exist (and so have been explored) >>> level1fog HexaryTrieFog # So we continue exploring. The fog helps choose which prefix to explore next: >>> level1fog.nearest_unknown() (0x6,) # We can also look for the nearest unknown key to a particular target >>> prefix = level1fog.nearest_unknown((8, 1)) (0x7,) >>> node7 = node.traverse(prefix) HexaryTrieNode(sub_segments=((0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6),), value=b'', suffix=(), raw=[b'\x00\x96\xf7W"\xd6', b"\xe2\xe2oN\xe1\xf8\xda\xc1\x8c\x03\x92'\x93\x805\xad-\xef\x07_\x0ePV\x1f\xb5/lVZ\xc6\xc1\xf9"]) # We found an extension node, and mark it in the fog # For simpliticy, we'll start clobbering the `fog` variable >>> fog = level1fog.explore(prefix, node7.sub_segments) HexaryTrieFog # Let's explore the next branch node and see what's left >>> prefix = fog.nearest_unknown((7,)) (0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6) >>> node796f75722d6 = t.traverse(prefix) HexaryTrieNode(sub_segments=((0xb,), (0xf,)), value=b'', suffix=(), raw=[b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', [b' ey', b'your-value'], b'', b'', b'', [b' ther-key', b'your-other-value'], b'']) # Notice that the branch node inlines the values, but the fog and annotated node ignore them for now >>> fog = fog.explore(prefix, node796f75722d6.sub_segments) HexaryTrieFog # Index keys may not matter for some use cases, so we can leave them out # entirely, like nearest_unknown(). # There's one more feature to consider: we can look directionally to the right # of an index for the nearest prefix. >>> prefix = fog.nearest_right((0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xc)) (0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xf) # That same index key would give a closer prefix to the left if direction didn't matter # (See the difference in the very last nibble) >>> fog.nearest_unknown((0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xc)) (0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb) # So we traverse to this last embedded leaf node at `prefix` >>> a_leaf_node = t.traverse(prefix) HexaryTrieNode(sub_segments=(), value=b'your-other-value', suffix=(0x7, 0x4, 0x6, 0x8, 0x6, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb, 0x6, 0x5, 0x7, 0x9), raw=[b' ther-key', b'your-other-value']) # we mark the prefix as fully explored like so: >>> fog = fog.explore(prefix, a_leaf_node.sub_segments) HexaryTrieFog # Notice that sub_segments was empty, and the prefix has disappeared from our list of unexplored prefixes # So far we have dealt with an un-changing trie, but what if it is # modified while we are working on it? >>> del t[b'your-other-key'] >>> t[b'your-key-rebranched'] = b'your-value' >>> t.root_hash b'"\xc0\xcaQ\xa7X\x08E\xb5"A\xde\xbfY\xeb"XY\xb1O\x034=\x04\x06\xa9li\xd8\x92\xadP' # The unexplored prefixes we have before might not exist anymore. They might: # 1. have been deleted entirely, in which case, we will get a blank node, and need no special treatment # 2. lead us into the middle of a leaf or extension node, which makes things tricky >>> prefix = fog.nearest_unknown((8,)) (0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb) >>> t.traverse(prefix) TraversedPartialPath: Could not traverse through HexaryTrieNode(sub_segments=((0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb, 0x6, 0x5, 0x7, 0x9),), value=b'', suffix=(), raw=[b'\x19our-key', b'f\xbe\x88\x8f#\xd5\x15-8\xc0\x1f\xfb\xf7\x8b=\x98\x86 \xec\xdeK\x07\xc8\xbf\xa7\x93\xfa\x9e\xc1\x89@\x00']) at (0x7,), only partially traversed with: (0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb) # Let's drill into what this means: # - We fully traversed to a node at prefix (7,) # - We tried to traverse into the rest of the prefix # - We only got part-way through the extension node: (0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb) # - The extension node full sub-segment is actually: (0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb, 0x6, 0x5, 0x7, 0x9) # So what do we do about it? Catch the exception, and explore with the fog slightly differently >>> from trie.exceptions import TraversedPartialPath >>> last_exception = None >>> try: t.traverse(prefix) except TraversedPartialPath as exc: last_exception = exc # We can now continue exploring the children of the extension node, by using an attribute on the exception: >>> sub_segments = last_exception.simulated_node.sub_segments ((0x6, 0x5, 0x7, 0x9),) # Note that this sub-segment now carries us the rest of the way to the child # of the node that we only partially traversed into. # This "simulated_node" is created by slicing the extension node in two: the # first extension node having the path that we (partially) traversed, and the second # extension node being the child of that parent, which continues on to point to # the child of the original extension. # If the exception is raised on a leaf node, then the leaf node is sliced into # an extension and another shorter leaf node. >>> fog = fog.explore(prefix, sub_segments) HexaryTrieFog # So now we can pick up where we left off, traversing to the child of the extension node, and so on. >>> prefix = fog.nearest_unknown((8,)) (0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb, 0x6, 0x5, 0x7, 0x9) # The following will not raise a TraversedPartialPath exception, because we know that # a node was at the path, and the trie hasn't changed: >>> t.traverse(prefix) HexaryTrieNode(sub_segments=((0x2,),), value=b'your-value', suffix=(), raw=[b'', b'', [b'=rebranched', b'your-value'], b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'your-value']) # etc... ``` **Note**: `traverse()` will access the database for every node from the root to the target node. If navigating a large trie, consider using `TrieFrontierCache` and `HexaryTrie.traverse_from()` to minimize database lookups. See the tests in `tests/test_hexary_trie_walk.py` for some examples. ## BinaryTrie **Note:** One drawback of Binary Trie is that **one key can not be the prefix of another key**. For example, if you already set the value `value1` with key `key1`, you can not set another value with key `key` or `key11` and the like. ### BinaryTrie branch and witness helper functions ```python >>> from trie import BinaryTrie >>> from trie.branches import ( >>> check_if_branch_exist, >>> get_branch, >>> if_branch_valid, >>> get_witness_for_key_prefix, >>> ) >>> t = BinaryTrie(db={}) >>> t.root_hash b"\xc5\xd2F\x01\x86\xf7#<\x92~}\xb2\xdc\xc7\x03\xc0\xe5\x00\xb6S\xca\x82';{\xfa\xd8\x04]\x85\xa4p" >>> t.set(b'key1', b'value1') >>> t.set(b'key2', b'value2') ``` Now Trie looks like this: ``` root ---> (kvnode, *common key prefix*) | | | (branchnode) / \ / \ / \ (kvnode, *remain kepath*)(kvnode, *remain kepath*) | | | | | | (leafnode, b'value1') (leafnode, b'value2') ``` ```python >>> # check_if_branch_exist function >>> check_if_branch_exist(t.db, t.root_hash, b'key') True >>> check_if_branch_exist(t.db, t.root_hash, b'key1') True >>> check_if_branch_exist(t.db, t.root_hash, b'ken') False >>> check_if_branch_exist(t.db, t.root_hash, b'key123') False >>> # get_branch function >>> get_branch(t.db, t.root_hash, b'key1') (b'\x00\x82\x1a\xd9^L|38J\xed\xf31S\xb2\x97A\x8dy\x91RJ\x92\xf5ZC\xb4\x99T&;!\x9f\xa9!\xa2\xfe;', b"\x01*\xaccxH\x89\x08}\x93|\xda\xb9\r\x9b\x82\x8b\xb2Y\xbc\x10\xb9\x88\xf40\xef\xed\x8b'\x13\xbc\xa5\xccYGb\xc2\x8db\x88lPs@)\x86v\xd7B\xf7\xd3X\x93\xc9\xf0\xfd\xae\xe0`j#\x0b\xca;\xf8", b'\x00\x11\x8aEL3\x839E\xbd\xc4G\xd1xj\x0fxWu\xcb\xf6\xf3\xf2\x8e7!M\xca\x1c/\xd7\x7f\xed\xc6', b'\x02value1') ``` Node started with `b'\x00'`, `b'\x01'` and `b'\x02'` are kvnode, branchnode and leafnode respectively. ```python >>> get_branch(t.db, t.root_hash, b'key') (b'\x00\x82\x1a\xd9^L|38J\xed\xf31S\xb2\x97A\x8dy\x91RJ\x92\xf5ZC\xb4\x99T&;!\x9f\xa9!\xa2\xfe;',) >>> get_branch(t.db, t.root_hash, b'key123') # InvalidKeyError >>> get_branch(t.db, t.root_hash, b'key5') # there is still branch for non-exist key (b'\x00\x82\x1a\xd9^L|38J\xed\xf31S\xb2\x97A\x8dy\x91RJ\x92\xf5ZC\xb4\x99T&;!\x9f\xa9!\xa2\xfe;',) >>> # if_branch_valid function >>> v = t.get(b'key1') >>> b = get_branch(t.db, t.root_hash, b'key1') >>> if_branch_valid(b, t.root_hash, b'key1', v) True >>> v = t.get(b'key5') # v should be None >>> b = get_branch(t.db, t.root_hash, b'key5') >>> if_branch_valid(b, t.root_hash, b'key5', v) True >>> v = t.get(b'key1') >>> b = get_branch(t.db, t.root_hash, b'key2') >>> if_branch_valid(b, t.root_hash, b'key1', v) # KeyError >>> if_branch_valid([], t.root_hash, b'key1', v) # AssertionError >>> # get_witness_for_key_prefix function >>> get_witness_for_key_prefix(t.db, t.root_hash, b'key1') # equivalent to `get_branch(t.db, t.root_hash, b'key1')` (b'\x00\x82\x1a\xd9^L|38J\xed\xf31S\xb2\x97A\x8dy\x91RJ\x92\xf5ZC\xb4\x99T&;!\x9f\xa9!\xa2\xfe;', b"\x01*\xaccxH\x89\x08}\x93|\xda\xb9\r\x9b\x82\x8b\xb2Y\xbc\x10\xb9\x88\xf40\xef\xed\x8b'\x13\xbc\xa5\xccYGb\xc2\x8db\x88lPs@)\x86v\xd7B\xf7\xd3X\x93\xc9\xf0\xfd\xae\xe0`j#\x0b\xca;\xf8", b'\x00\x11\x8aEL3\x839E\xbd\xc4G\xd1xj\x0fxWu\xcb\xf6\xf3\xf2\x8e7!M\xca\x1c/\xd7\x7f\xed\xc6', b'\x02value1') >>> get_witness_for_key_prefix(t.db, t.root_hash, b'key') # this will include additional nodes of b'key2' (b'\x00\x82\x1a\xd9^L|38J\xed\xf31S\xb2\x97A\x8dy\x91RJ\x92\xf5ZC\xb4\x99T&;!\x9f\xa9!\xa2\xfe;', b"\x01*\xaccxH\x89\x08}\x93|\xda\xb9\r\x9b\x82\x8b\xb2Y\xbc\x10\xb9\x88\xf40\xef\xed\x8b'\x13\xbc\xa5\xccYGb\xc2\x8db\x88lPs@)\x86v\xd7B\xf7\xd3X\x93\xc9\xf0\xfd\xae\xe0`j#\x0b\xca;\xf8", b'\x00\x11\x8aEL3\x839E\xbd\xc4G\xd1xj\x0fxWu\xcb\xf6\xf3\xf2\x8e7!M\xca\x1c/\xd7\x7f\xed\xc6', b'\x02value1', b'\x00\x10O\xa9\x0b\x1c!_`<\xb5^\x98D\x89\x17\x148\xac\xda&\xb3P\xf6\x06[\x1b9\xc09\xbas\x85\xf5', b'\x02value2') >>> get_witness_for_key_prefix(t.db, t.root_hash, b'') # this will return the whole trie ``` %package help Summary: Development documents and examples for trie Provides: python3-trie-doc %description help # Python Implementation of the Ethereum Trie structure [![PyPI](https://img.shields.io/pypi/v/trie.svg)](https://pypi.org/project/trie/) ![PyPI - Python Version](https://img.shields.io/pypi/pyversions/trie.svg) > This library and repository was previously located at [pipermerriam/py-trie](https://github.com/pipermerriam/py-trie). It was transferred to the Ethereum foundation GitHub in > November 2017 and renamed to `py-trie`. ## Installation ```sh pip install trie ``` ## Development ```sh pip install -e .[dev] ``` ### Running the tests You can run the tests with: ```sh pytest tests ``` Or you can install `tox` to run the full test suite. ### Releasing Pandoc is required for transforming the markdown README to the proper format to render correctly on pypi. For Debian-like systems: ```sh apt install pandoc ``` Or on OSX: ```sh brew install pandoc ``` To release a new version: ```sh make release bump=$$VERSION_PART_TO_BUMP$$ ``` #### How to bumpversion The version format for this repo is `{major}.{minor}.{patch}` for stable, and `{major}.{minor}.{patch}-{stage}.{devnum}` for unstable (`stage` can be alpha or beta). To issue the next version in line, use bumpversion and specify which part to bump, like `bumpversion minor` or `bumpversion devnum`. If you are in a beta version, `bumpversion stage` will switch to a stable. To issue an unstable version when the current version is stable, specify the new version explicitly, like `bumpversion --new-version 4.0.0-alpha.1 devnum` ## Usage ```python >>> from trie import HexaryTrie >>> t = HexaryTrie(db={}) >>> t.root_hash b'V\xe8\x1f\x17\x1b\xccU\xa6\xff\x83E\xe6\x92\xc0\xf8n[H\xe0\x1b\x99l\xad\xc0\x01b/\xb5\xe3c\xb4!' >>> t.set(b'my-key', b'some-value') >>> t.get(b'my-key') b'some-value' >>> t.exists(b'another-key') False >>> t.set(b'another-key', b'another-value') >>> t.exists(b'another-key') True >>> t.delete(b'another-key') >>> t.exists(b'another-key') False ``` You can also use it like a dictionary. ```python >>> from trie import HexaryTrie >>> t = HexaryTrie(db={}) >>> t.root_hash b'V\xe8\x1f\x17\x1b\xccU\xa6\xff\x83E\xe6\x92\xc0\xf8n[H\xe0\x1b\x99l\xad\xc0\x01b/\xb5\xe3c\xb4!' >>> t[b'my-key'] = b'some-value' >>> t[b'my-key'] b'some-value' >>> b'another-key' in t False >>> t[b'another-key'] = b'another-value' >>> b'another-key' in t True >>> del t[b'another-key'] >>> b'another-key' in t False ``` ### Traversing (inspecting trie internals) ```python >>> from trie import HexaryTrie >>> t = HexaryTrie(db={}) >>> t.root_hash b'V\xe8\x1f\x17\x1b\xccU\xa6\xff\x83E\xe6\x92\xc0\xf8n[H\xe0\x1b\x99l\xad\xc0\x01b/\xb5\xe3c\xb4!' >>> t[b'my-key'] = b'some-value' >>> t[b'my-other-key'] = b'another-value' # Look at the root node: >>> root_node = t.traverse(()) >>> root_node HexaryTrieNode(sub_segments=((0x6, 0xd, 0x7, 0x9, 0x2, 0xd, 0x6),), value=b'', suffix=(), raw=[b'\x16\xd7\x92\xd6', b'\xb4q\xb8h\xec\x1c\xe1\xf4\\\x88\xda\xb4\xc1\xc2n\xbaw\xd0\x9c\xf1\xacV\xb4Dk\xa7\xe6\xd7qf\xc2\x82']) # the root node is an extension down, because the first 7 nibbles are the same between the two keys # Let's walk down to the child of that extension >>> prefix6d792d6 = t.traverse(root_node.sub_segments[0]) >>> prefix6d792d6 HexaryTrieNode(sub_segments=((0xb,), (0xf,)), value=b'', suffix=(), raw=[b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', [b' ey', b'some-value'], b'', b'', b'', [b' ther-key', b'another-value'], b'']) # A branch node separates the second nibbles of b'k' and b'o': 0xb and 0xf # Notice the position of the children in the 11th and 15th index # Another way to get there without loading the root node from the database is using traverse_from: >>> assert t.traverse_from(root_node, root_node.sub_segments[0]) == prefix6d792d6 # Embedded nodes can be traversed to the same way as nodes stored in the database: >>> t.traverse(root_node.sub_segments[0] + (0xb,)) HexaryTrieNode(sub_segments=(), value=b'some-value', suffix=(0x6, 0x5, 0x7, 0x9), raw=[b' ey', b'some-value']) # This leaf node includes the suffix (the rest of the key, in nibbles, that haven't been traversed, # just b'ey': 0x6579 ``` ### Walking a full trie To walk through the full trie (for example, to verify that all node bodies are present in the database), use HexaryTrieFog and the traversal API above. For example: ```python >>> from trie import HexaryTrie >>> t = HexaryTrie(db={}) >>> t.root_hash b'V\xe8\x1f\x17\x1b\xccU\xa6\xff\x83E\xe6\x92\xc0\xf8n[H\xe0\x1b\x99l\xad\xc0\x01b/\xb5\xe3c\xb4!' >>> t[b'my-key'] = b'some-value' >>> t[b'my-other-key'] = b'another-value' >>> t[b'your-key'] = b'your-value' >>> t[b'your-other-key'] = b'your-other-value' >>> t.root_hash b'\xf8\xdd\xe4\x0f\xaa\xf4P7\xfa$\xfde>\xec\xb4i\x00N\xa3)\xcf\xef\x80\xc4YU\xe8\xe7\xbf\xa89\xd5' # Initialize a fog object to track unexplored prefixes in a trie walk >>> from from trie.fog import HexaryTrieFog >>> empty_fog = HexaryTrieFog() # At the beginning, the unexplored prefix is (), which means that none of the trie has been explored >>> prefix = empty_fog.nearest_unknown() () # So we start by exploring the node at prefix () -- which is the root node: >>> node = t.traverse(prefix) HexaryTrieNode(sub_segments=((0x6,), (0x7,)), value=b'', suffix=(), raw=[b'', b'', b'', b'', b'', b'', b"\x03\xd2vk\x85\xce\xe1\xa8\xdb'F\x8c\xe5\x15\xc6\n+M:th\xa1\\\xb13\xcc\xe8\xd0\x1d\xa7\xa8U", b"\x1b\x8d'\xb3\x99(yX\xaa\x96C!\xba'X \xbb|\xa6,\xb5V!\xd3\x1a\x05\xe5\xbf\x02\xa3fR", b'', b'', b'', b'', b'', b'', b'', b'', b'']) # and mark the root as explored, while defining the unexplored children: >>> level1fog = empty_fog.explore(prefix, node.sub_segments) # Now the unexplored prefixes are the keys starting with the four bits 6 and the four bits 7. # All other keys are known to not exist (and so have been explored) >>> level1fog HexaryTrieFog # So we continue exploring. The fog helps choose which prefix to explore next: >>> level1fog.nearest_unknown() (0x6,) # We can also look for the nearest unknown key to a particular target >>> prefix = level1fog.nearest_unknown((8, 1)) (0x7,) >>> node7 = node.traverse(prefix) HexaryTrieNode(sub_segments=((0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6),), value=b'', suffix=(), raw=[b'\x00\x96\xf7W"\xd6', b"\xe2\xe2oN\xe1\xf8\xda\xc1\x8c\x03\x92'\x93\x805\xad-\xef\x07_\x0ePV\x1f\xb5/lVZ\xc6\xc1\xf9"]) # We found an extension node, and mark it in the fog # For simpliticy, we'll start clobbering the `fog` variable >>> fog = level1fog.explore(prefix, node7.sub_segments) HexaryTrieFog # Let's explore the next branch node and see what's left >>> prefix = fog.nearest_unknown((7,)) (0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6) >>> node796f75722d6 = t.traverse(prefix) HexaryTrieNode(sub_segments=((0xb,), (0xf,)), value=b'', suffix=(), raw=[b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', [b' ey', b'your-value'], b'', b'', b'', [b' ther-key', b'your-other-value'], b'']) # Notice that the branch node inlines the values, but the fog and annotated node ignore them for now >>> fog = fog.explore(prefix, node796f75722d6.sub_segments) HexaryTrieFog # Index keys may not matter for some use cases, so we can leave them out # entirely, like nearest_unknown(). # There's one more feature to consider: we can look directionally to the right # of an index for the nearest prefix. >>> prefix = fog.nearest_right((0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xc)) (0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xf) # That same index key would give a closer prefix to the left if direction didn't matter # (See the difference in the very last nibble) >>> fog.nearest_unknown((0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xc)) (0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb) # So we traverse to this last embedded leaf node at `prefix` >>> a_leaf_node = t.traverse(prefix) HexaryTrieNode(sub_segments=(), value=b'your-other-value', suffix=(0x7, 0x4, 0x6, 0x8, 0x6, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb, 0x6, 0x5, 0x7, 0x9), raw=[b' ther-key', b'your-other-value']) # we mark the prefix as fully explored like so: >>> fog = fog.explore(prefix, a_leaf_node.sub_segments) HexaryTrieFog # Notice that sub_segments was empty, and the prefix has disappeared from our list of unexplored prefixes # So far we have dealt with an un-changing trie, but what if it is # modified while we are working on it? >>> del t[b'your-other-key'] >>> t[b'your-key-rebranched'] = b'your-value' >>> t.root_hash b'"\xc0\xcaQ\xa7X\x08E\xb5"A\xde\xbfY\xeb"XY\xb1O\x034=\x04\x06\xa9li\xd8\x92\xadP' # The unexplored prefixes we have before might not exist anymore. They might: # 1. have been deleted entirely, in which case, we will get a blank node, and need no special treatment # 2. lead us into the middle of a leaf or extension node, which makes things tricky >>> prefix = fog.nearest_unknown((8,)) (0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb) >>> t.traverse(prefix) TraversedPartialPath: Could not traverse through HexaryTrieNode(sub_segments=((0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb, 0x6, 0x5, 0x7, 0x9),), value=b'', suffix=(), raw=[b'\x19our-key', b'f\xbe\x88\x8f#\xd5\x15-8\xc0\x1f\xfb\xf7\x8b=\x98\x86 \xec\xdeK\x07\xc8\xbf\xa7\x93\xfa\x9e\xc1\x89@\x00']) at (0x7,), only partially traversed with: (0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb) # Let's drill into what this means: # - We fully traversed to a node at prefix (7,) # - We tried to traverse into the rest of the prefix # - We only got part-way through the extension node: (0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb) # - The extension node full sub-segment is actually: (0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb, 0x6, 0x5, 0x7, 0x9) # So what do we do about it? Catch the exception, and explore with the fog slightly differently >>> from trie.exceptions import TraversedPartialPath >>> last_exception = None >>> try: t.traverse(prefix) except TraversedPartialPath as exc: last_exception = exc # We can now continue exploring the children of the extension node, by using an attribute on the exception: >>> sub_segments = last_exception.simulated_node.sub_segments ((0x6, 0x5, 0x7, 0x9),) # Note that this sub-segment now carries us the rest of the way to the child # of the node that we only partially traversed into. # This "simulated_node" is created by slicing the extension node in two: the # first extension node having the path that we (partially) traversed, and the second # extension node being the child of that parent, which continues on to point to # the child of the original extension. # If the exception is raised on a leaf node, then the leaf node is sliced into # an extension and another shorter leaf node. >>> fog = fog.explore(prefix, sub_segments) HexaryTrieFog # So now we can pick up where we left off, traversing to the child of the extension node, and so on. >>> prefix = fog.nearest_unknown((8,)) (0x7, 0x9, 0x6, 0xf, 0x7, 0x5, 0x7, 0x2, 0x2, 0xd, 0x6, 0xb, 0x6, 0x5, 0x7, 0x9) # The following will not raise a TraversedPartialPath exception, because we know that # a node was at the path, and the trie hasn't changed: >>> t.traverse(prefix) HexaryTrieNode(sub_segments=((0x2,),), value=b'your-value', suffix=(), raw=[b'', b'', [b'=rebranched', b'your-value'], b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'', b'your-value']) # etc... ``` **Note**: `traverse()` will access the database for every node from the root to the target node. If navigating a large trie, consider using `TrieFrontierCache` and `HexaryTrie.traverse_from()` to minimize database lookups. See the tests in `tests/test_hexary_trie_walk.py` for some examples. ## BinaryTrie **Note:** One drawback of Binary Trie is that **one key can not be the prefix of another key**. For example, if you already set the value `value1` with key `key1`, you can not set another value with key `key` or `key11` and the like. ### BinaryTrie branch and witness helper functions ```python >>> from trie import BinaryTrie >>> from trie.branches import ( >>> check_if_branch_exist, >>> get_branch, >>> if_branch_valid, >>> get_witness_for_key_prefix, >>> ) >>> t = BinaryTrie(db={}) >>> t.root_hash b"\xc5\xd2F\x01\x86\xf7#<\x92~}\xb2\xdc\xc7\x03\xc0\xe5\x00\xb6S\xca\x82';{\xfa\xd8\x04]\x85\xa4p" >>> t.set(b'key1', b'value1') >>> t.set(b'key2', b'value2') ``` Now Trie looks like this: ``` root ---> (kvnode, *common key prefix*) | | | (branchnode) / \ / \ / \ (kvnode, *remain kepath*)(kvnode, *remain kepath*) | | | | | | (leafnode, b'value1') (leafnode, b'value2') ``` ```python >>> # check_if_branch_exist function >>> check_if_branch_exist(t.db, t.root_hash, b'key') True >>> check_if_branch_exist(t.db, t.root_hash, b'key1') True >>> check_if_branch_exist(t.db, t.root_hash, b'ken') False >>> check_if_branch_exist(t.db, t.root_hash, b'key123') False >>> # get_branch function >>> get_branch(t.db, t.root_hash, b'key1') (b'\x00\x82\x1a\xd9^L|38J\xed\xf31S\xb2\x97A\x8dy\x91RJ\x92\xf5ZC\xb4\x99T&;!\x9f\xa9!\xa2\xfe;', b"\x01*\xaccxH\x89\x08}\x93|\xda\xb9\r\x9b\x82\x8b\xb2Y\xbc\x10\xb9\x88\xf40\xef\xed\x8b'\x13\xbc\xa5\xccYGb\xc2\x8db\x88lPs@)\x86v\xd7B\xf7\xd3X\x93\xc9\xf0\xfd\xae\xe0`j#\x0b\xca;\xf8", b'\x00\x11\x8aEL3\x839E\xbd\xc4G\xd1xj\x0fxWu\xcb\xf6\xf3\xf2\x8e7!M\xca\x1c/\xd7\x7f\xed\xc6', b'\x02value1') ``` Node started with `b'\x00'`, `b'\x01'` and `b'\x02'` are kvnode, branchnode and leafnode respectively. ```python >>> get_branch(t.db, t.root_hash, b'key') (b'\x00\x82\x1a\xd9^L|38J\xed\xf31S\xb2\x97A\x8dy\x91RJ\x92\xf5ZC\xb4\x99T&;!\x9f\xa9!\xa2\xfe;',) >>> get_branch(t.db, t.root_hash, b'key123') # InvalidKeyError >>> get_branch(t.db, t.root_hash, b'key5') # there is still branch for non-exist key (b'\x00\x82\x1a\xd9^L|38J\xed\xf31S\xb2\x97A\x8dy\x91RJ\x92\xf5ZC\xb4\x99T&;!\x9f\xa9!\xa2\xfe;',) >>> # if_branch_valid function >>> v = t.get(b'key1') >>> b = get_branch(t.db, t.root_hash, b'key1') >>> if_branch_valid(b, t.root_hash, b'key1', v) True >>> v = t.get(b'key5') # v should be None >>> b = get_branch(t.db, t.root_hash, b'key5') >>> if_branch_valid(b, t.root_hash, b'key5', v) True >>> v = t.get(b'key1') >>> b = get_branch(t.db, t.root_hash, b'key2') >>> if_branch_valid(b, t.root_hash, b'key1', v) # KeyError >>> if_branch_valid([], t.root_hash, b'key1', v) # AssertionError >>> # get_witness_for_key_prefix function >>> get_witness_for_key_prefix(t.db, t.root_hash, b'key1') # equivalent to `get_branch(t.db, t.root_hash, b'key1')` (b'\x00\x82\x1a\xd9^L|38J\xed\xf31S\xb2\x97A\x8dy\x91RJ\x92\xf5ZC\xb4\x99T&;!\x9f\xa9!\xa2\xfe;', b"\x01*\xaccxH\x89\x08}\x93|\xda\xb9\r\x9b\x82\x8b\xb2Y\xbc\x10\xb9\x88\xf40\xef\xed\x8b'\x13\xbc\xa5\xccYGb\xc2\x8db\x88lPs@)\x86v\xd7B\xf7\xd3X\x93\xc9\xf0\xfd\xae\xe0`j#\x0b\xca;\xf8", b'\x00\x11\x8aEL3\x839E\xbd\xc4G\xd1xj\x0fxWu\xcb\xf6\xf3\xf2\x8e7!M\xca\x1c/\xd7\x7f\xed\xc6', b'\x02value1') >>> get_witness_for_key_prefix(t.db, t.root_hash, b'key') # this will include additional nodes of b'key2' (b'\x00\x82\x1a\xd9^L|38J\xed\xf31S\xb2\x97A\x8dy\x91RJ\x92\xf5ZC\xb4\x99T&;!\x9f\xa9!\xa2\xfe;', b"\x01*\xaccxH\x89\x08}\x93|\xda\xb9\r\x9b\x82\x8b\xb2Y\xbc\x10\xb9\x88\xf40\xef\xed\x8b'\x13\xbc\xa5\xccYGb\xc2\x8db\x88lPs@)\x86v\xd7B\xf7\xd3X\x93\xc9\xf0\xfd\xae\xe0`j#\x0b\xca;\xf8", b'\x00\x11\x8aEL3\x839E\xbd\xc4G\xd1xj\x0fxWu\xcb\xf6\xf3\xf2\x8e7!M\xca\x1c/\xd7\x7f\xed\xc6', b'\x02value1', b'\x00\x10O\xa9\x0b\x1c!_`<\xb5^\x98D\x89\x17\x148\xac\xda&\xb3P\xf6\x06[\x1b9\xc09\xbas\x85\xf5', b'\x02value2') >>> get_witness_for_key_prefix(t.db, t.root_hash, b'') # this will return the whole trie ``` %prep %autosetup -n trie-2.1.0 %build %py3_build %install %py3_install install -d -m755 %{buildroot}/%{_pkgdocdir} if [ -d doc ]; then cp -arf doc %{buildroot}/%{_pkgdocdir}; fi if [ -d docs ]; then cp -arf docs %{buildroot}/%{_pkgdocdir}; fi if [ -d example ]; then cp -arf example %{buildroot}/%{_pkgdocdir}; fi if [ -d examples ]; then cp -arf examples %{buildroot}/%{_pkgdocdir}; fi pushd %{buildroot} if [ -d usr/lib ]; then find usr/lib -type f -printf "/%h/%f\n" >> filelist.lst fi if [ -d usr/lib64 ]; then find usr/lib64 -type f -printf "/%h/%f\n" >> filelist.lst fi if [ -d usr/bin ]; then find usr/bin -type f -printf "/%h/%f\n" >> filelist.lst fi if [ -d usr/sbin ]; then find usr/sbin -type f -printf "/%h/%f\n" >> filelist.lst fi touch doclist.lst if [ -d usr/share/man ]; then find usr/share/man -type f -printf "/%h/%f.gz\n" >> doclist.lst fi popd mv %{buildroot}/filelist.lst . mv %{buildroot}/doclist.lst . %files -n python3-trie -f filelist.lst %dir %{python3_sitelib}/* %files help -f doclist.lst %{_docdir}/* %changelog * Sun Apr 23 2023 Python_Bot - 2.1.0-1 - Package Spec generated