Change crash keys to be registered with a maximum length instead of number of chunks.

base/debug/crash_logging.cc

Index: base/debug/crash_logging.cc
diff --git a/base/debug/crash_logging.cc b/base/debug/crash_logging.cc
index 604c28620ec1cb9a7e783d6bc42b44ddb9051720..d7ea283a7c0145c39408931f151cfb086cf67430 100644
--- a/base/debug/crash_logging.cc
+++ b/base/debug/crash_logging.cc
@@ -41,7 +41,7 @@ void SetCrashKeyValue(const base::StringPiece& key,
   //                  << "(key = " << key << ")";
 
   // Handle the un-chunked case.
-  if (!crash_key || crash_key->num_chunks == 1) {
+  if (!crash_key || crash_key->max_length <= g_chunk_max_length_) {
     g_set_key_func_(key, value);
     return;
   }
@@ -49,7 +49,9 @@ void SetCrashKeyValue(const base::StringPiece& key,
   // Unset the unused chunks.
   std::vector<std::string> chunks =
       ChunkCrashKeyValue(*crash_key, value, g_chunk_max_length_);
-  for (size_t i = chunks.size(); i < crash_key->num_chunks; ++i) {
+  for (size_t i = chunks.size();
+       i < crash_key->max_length / g_chunk_max_length_;
+       ++i) {
     g_clear_key_func_(base::StringPrintf(kChunkFormatString, key.data(), i+1));
   }
 
@@ -67,12 +69,12 @@ void ClearCrashKey(const base::StringPiece& key) {
   const CrashKey* crash_key = LookupCrashKey(key);
 
   // Handle the un-chunked case.
-  if (!crash_key || crash_key->num_chunks == 1) {
+  if (!crash_key || crash_key->max_length <= g_chunk_max_length_) {
     g_clear_key_func_(key);
     return;
   }
 
-  for (size_t i = 0; i < crash_key->num_chunks; ++i) {
+  for (size_t i = 0; i < crash_key->max_length / g_chunk_max_length_; ++i) {
     g_clear_key_func_(base::StringPrintf(kChunkFormatString, key.data(), i+1));
   }
 }
@@ -136,7 +138,7 @@ size_t InitCrashKeys(const CrashKey* const keys, size_t count,
   size_t total_keys = 0;
   for (size_t i = 0; i < count; ++i) {
     g_crash_keys_->insert(std::make_pair(keys[i].key_name, keys[i]));
-    total_keys += keys[i].num_chunks;
+    total_keys += keys[i].max_length / chunk_max_length;
   }
   DCHECK_EQ(count, g_crash_keys_->size())
       << "Duplicate crash keys were registered";
@@ -161,11 +163,9 @@ void SetCrashKeyReportingFunctions(
 std::vector<std::string> ChunkCrashKeyValue(const CrashKey& crash_key,
                                             const base::StringPiece& value,
                                             size_t chunk_max_length) {
-  std::string value_string = value.as_string();
+  std::string value_string = value.substr(0, crash_key.max_length).as_string();

[eroman, 2013/02/20 00:08:43]

Is this restriction necessary? Assuming implementations use fixed sized buffers
for the chunks, may as well truncate at a multiple of the chunk size.

[Robert Sesek, 2013/02/27 18:52:49]

At this layer, I think it makes more sense to deal in lengths rather than chunk
sizes since this doesn't know about Breakpad, and thus the sizes, at all. I do
expect in practice that lengths will be multiples of the chunk sizes, which is
why those constants exist in crash_keys.cc.

   std::vector<std::string> chunks;
-  for (size_t i = 0, offset = 0;
-       i < crash_key.num_chunks && offset < value_string.length();
-       ++i) {
+  for (size_t offset = 0; offset < value_string.length(); ) {
     std::string chunk = value_string.substr(offset, chunk_max_length);
     chunks.push_back(chunk);
     offset += chunk.length();