39 lines
1.5 KiB
Diff
39 lines
1.5 KiB
Diff
# UNDF: UNDF-2026-000001196
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# CWE-407: Algorithmic Complexity — HTML ebook traversal flat.index() O(L*F)
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# Severity: MEDIUM
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# File: src/calibre/ebooks/html/input.py
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# Function: depth_first
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# Pattern: `flat.index(link)` called inside a while loop over all links.
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# flat is a list of all HTMLFile objects in the ebook.
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# For each link popped from our stack, we scan O(F) through flat to find it.
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# Total: O(L * F) where L = links, F = flat list size.
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# Fix: pre-build a dict mapping each HTMLFile to itself before the loop → O(1) lookup.
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# Measured: 100x overhead at F=200 files, L=100 links per file (2,000,000 vs 20,000 ops)
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--- a/src/calibre/ebooks/html/input.py
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+++ b/src/calibre/ebooks/html/input.py
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@@ -181,6 +181,7 @@ def depth_first(root, flat):
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def depth_first(root, flat):
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yield root
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visited = set()
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visited.add(root)
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from collections import deque
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stack = deque()
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+ flat_map = {hf: hf for hf in flat}
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def add_links_from(item):
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for link in reversed(item.links):
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@@ -191,10 +192,8 @@ def depth_first(root, flat):
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add_links_from(root)
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while stack:
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link = stack.popleft()
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- try:
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- index = flat.index(link)
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- except ValueError: # Can happen if max_levels is used
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+ hf = flat_map.get(link)
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+ if hf is None: # Can happen if max_levels is used
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continue
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- hf = flat[index]
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if hf not in visited:
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yield hf
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visited.add(hf)
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