publicsuffix: add some commentary on using "go run gen.go".
Also add more detail to some code-gen error messages.
Change-Id: I776609435d3b27d2fffd48046f98fb0b098451c5
Reviewed-on: https://go-review.googlesource.com/19440
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/publicsuffix/gen.go b/publicsuffix/gen.go
index ee2598c..e82b797 100644
--- a/publicsuffix/gen.go
+++ b/publicsuffix/gen.go
@@ -12,6 +12,16 @@
// go run gen.go -version "xxx" >table.go
// go run gen.go -version "xxx" -test >table_test.go
//
+// The first of those two will take around 20 minutes to complete, as the final
+// table is optimized for size. When testing the code generation workflow, pass
+// -crush=false to skip this optimization step, although the results of such a
+// run should not be committed, as the generated table can be around 50% larger
+// and, more importantly, require a larger number of scarce node table bits.
+// You may need to increase nodesBitsTextOffset or other constants to generate
+// a table with -crush=false.
+//
+// Pass -v to print verbose progress information.
+//
// The version is derived from information found at
// https://github.com/publicsuffix/list/commits/master/public_suffix_list.dat
//
@@ -35,11 +45,13 @@
)
const (
+ // These sum of these four values must be no greater than 32.
nodesBitsChildren = 9
nodesBitsICANN = 1
nodesBitsTextOffset = 15
nodesBitsTextLength = 6
+ // These sum of these four values must be no greater than 32.
childrenBitsWildcard = 1
childrenBitsNodeType = 2
childrenBitsHi = 14
@@ -299,8 +311,11 @@
return fmt.Errorf("internal error: could not find %q in text %q", label, text)
}
maxTextOffset, maxTextLength = max(maxTextOffset, offset), max(maxTextLength, length)
- if offset >= 1<<nodesBitsTextOffset || length >= 1<<nodesBitsTextLength {
- return fmt.Errorf("text offset/length is too large: %d/%d", offset, length)
+ if offset >= 1<<nodesBitsTextOffset {
+ return fmt.Errorf("text offset %d is too large, or nodeBitsTextOffset is too small", offset)
+ }
+ if length >= 1<<nodesBitsTextLength {
+ return fmt.Errorf("text length %d is too large, or nodeBitsTextLength is too small", length)
}
labelEncoding[label] = uint32(offset)<<nodesBitsTextLength | uint32(length)
}
@@ -462,14 +477,17 @@
// Assign childrenIndex.
maxChildren = max(maxChildren, len(childrenEncoding))
if len(childrenEncoding) >= 1<<nodesBitsChildren {
- return fmt.Errorf("children table is too large")
+ return fmt.Errorf("children table size %d is too large, or nodeBitsChildren is too small", len(childrenEncoding))
}
n.childrenIndex = len(childrenEncoding)
lo := uint32(n.firstChild)
hi := lo + uint32(len(n.children))
maxLo, maxHi = u32max(maxLo, lo), u32max(maxHi, hi)
- if lo >= 1<<childrenBitsLo || hi >= 1<<childrenBitsHi {
- return fmt.Errorf("children lo/hi is too large: %d/%d", lo, hi)
+ if lo >= 1<<childrenBitsLo {
+ return fmt.Errorf("children lo %d is too large, or childrenBitsLo is too small", lo)
+ }
+ if hi >= 1<<childrenBitsHi {
+ return fmt.Errorf("children hi %d is too large, or childrenBitsHi is too small", hi)
}
enc := hi<<childrenBitsLo | lo
enc |= uint32(n.nodeType) << (childrenBitsLo + childrenBitsHi)
