Move ErrorDelegate to its own file and add static utility functions to ErrorDelegate

BUG=151841
Test=None
R=shess, erikwright
TBR=cpu

Review URL: https://chromiumcodereview.appspot.com/11141012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@162647 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 135 insertions, 28 deletions

diff --git a/sql/connection.h b/sql/connection.h
index 1aef064..319517e 100644
--- a/sql/connection.h
+++ b/sql/connection.h
@@ -83,17 +83,17 @@ class SQL_EXPORT ErrorDelegate {
  public:
   virtual ~ErrorDelegate();
 
-  // |error| is an sqlite result code as seen in sqlite\preprocessed\sqlite3.h
-  // |connection| is db connection where the error happened and |stmt| is
-  // our best guess at the statement that triggered the error.  Do not store
-  // these pointers.
+  // |error| is an sqlite result code as seen in sqlite3.h. |connection| is the
+  // db connection where the error happened and |stmt| is our best guess at the
+  // statement that triggered the error. Do not store these pointers.
   //
   // |stmt| MAY BE NULL if there is no statement causing the problem (i.e. on
   // initialization).
   //
-  // If the error condition has been fixed an the original statement succesfuly
-  // re-tried then returning SQLITE_OK is appropiate; otherwise is recomended
-  // that you return the original |error| or the appropiae error code.
+  // If the error condition has been fixed and the original statement succesfuly
+  // re-tried then returning SQLITE_OK is appropriate; otherwise it is
+  // recommended that you return the original |error| or the appropriate error
+  // code.
   virtual int OnError(int error, Connection* connection, Statement* stmt) = 0;
 };
 
diff --git a/sql/diagnostic_error_delegate.h b/sql/diagnostic_error_delegate.h
index 4b8ce32..78b3d9d 100644
--- a/sql/diagnostic_error_delegate.h
+++ b/sql/diagnostic_error_delegate.h
@@ -6,8 +6,8 @@
 #define SQL_DIAGNOSTIC_ERROR_DELEGATE_H_
 
 #include "base/logging.h"
-#include "base/metrics/histogram.h"
 #include "sql/connection.h"
+#include "sql/error_delegate_util.h"
 #include "sql/sql_export.h"
 
 namespace sql {
@@ -15,12 +15,8 @@ namespace sql {
 // This class handles the exceptional sqlite errors that we might encounter
 // if for example the db is corrupted. Right now we just generate a UMA
 // histogram for release and an assert for debug builds.
-//
-// Why is it a template you ask? well, that is a funny story. The histograms
-// need to be singletons that is why they are always static at the function
-// scope, but we cannot use the Singleton class because they are not default
-// constructible. The template parameter makes the compiler to create unique
-// classes that don't share the same static variable.
+// See error_delegate_util.h for an explanation as to why this class is a
+// template.
 template <class UniqueT>
 class DiagnosticErrorDelegate : public ErrorDelegate {
  public:
@@ -29,24 +25,12 @@ class DiagnosticErrorDelegate : public ErrorDelegate {
 
   virtual int OnError(int error, Connection* connection,
                       Statement* stmt) {
-    LOG(ERROR) << "sqlite error " << error
-               << ", errno " << connection->GetLastErrno()
-               << ": " << connection->GetErrorMessage();
-    RecordErrorInHistogram(error);
+    LogAndRecordErrorInHistogram<UniqueT>(error, connection);
     return error;
   }
 
  private:
-  static void RecordErrorInHistogram(int error) {
-    // Trim off the extended error codes.
-    error &= 0xff;
-
-    // The histogram values from sqlite result codes go currently from 1 to
-    // 26 currently but 50 gives them room to grow.
-    UMA_HISTOGRAM_ENUMERATION(UniqueT::name(), error, 50);
-  }
-
- DISALLOW_COPY_AND_ASSIGN(DiagnosticErrorDelegate);
+  DISALLOW_COPY_AND_ASSIGN(DiagnosticErrorDelegate);
 };
 
 }  // namespace sql
diff --git a/sql/error_delegate_util.cc b/sql/error_delegate_util.cc
new file mode 100644
index 0000000..37fe006
--- /dev/null
+++ b/sql/error_delegate_util.cc
@@ -0,0 +1,80 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "sql/error_delegate_util.h"
+
+#include "third_party/sqlite/sqlite3.h"
+
+namespace sql {
+
+bool IsErrorCatastrophic(int error) {
+  switch (error) {
+    case SQLITE_DONE:
+    case SQLITE_OK:
+      // Theoretically, the wrapped delegate might have resolved the error, and
+      // we would end up here.
+      return false;
+
+    case SQLITE_CORRUPT:
+    case SQLITE_NOTADB:
+      // Highly unlikely we would ever recover from these.
+      return true;
+
+    case SQLITE_CANTOPEN:
+      // TODO(erikwright): Figure out what this means.
+      return false;
+
+    case SQLITE_IOERR:
+      // This could be broken blocks, in which case deleting the DB would be a
+      // good idea. But it might also be transient.
+      // TODO(erikwright): Figure out if we can distinguish between the two,
+      // or determine through metrics analysis to what extent these failures are
+      // transient.
+      return false;
+
+    case SQLITE_BUSY:
+      // Presumably transient.
+      return false;
+
+    case SQLITE_TOOBIG:
+    case SQLITE_FULL:
+    case SQLITE_NOMEM:
+      // Not a problem with the database.
+      return false;
+
+    case SQLITE_READONLY:
+      // Presumably either transient or we don't have the privileges to
+      // move/delete the file anyway.
+      return false;
+
+    case SQLITE_CONSTRAINT:
+    case SQLITE_ERROR:
+      // These probgably indicate a programming error or a migration failure
+      // that we prefer not to mask.
+      return false;
+
+    case SQLITE_LOCKED:
+    case SQLITE_INTERNAL:
+    case SQLITE_PERM:
+    case SQLITE_ABORT:
+    case SQLITE_INTERRUPT:
+    case SQLITE_NOTFOUND:
+    case SQLITE_PROTOCOL:
+    case SQLITE_EMPTY:
+    case SQLITE_SCHEMA:
+    case SQLITE_MISMATCH:
+    case SQLITE_MISUSE:
+    case SQLITE_NOLFS:
+    case SQLITE_AUTH:
+    case SQLITE_FORMAT:
+    case SQLITE_RANGE:
+    case SQLITE_ROW:
+      // None of these appear in error reports, so for now let's not try to
+      // guess at how to handle them.
+      return false;
+  }
+  return false;
+}
+
+}  // namespace sql
diff --git a/sql/error_delegate_util.h b/sql/error_delegate_util.h
new file mode 100644
index 0000000..6b90ccf
--- /dev/null
+++ b/sql/error_delegate_util.h
@@ -0,0 +1,41 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SQL_ERROR_DELEGATE_UTIL_H_
+#define SQL_ERROR_DELEGATE_UTIL_H_
+
+#include "base/metrics/histogram.h"
+#include "sql/connection.h"
+#include "sql/sql_export.h"
+
+namespace sql {
+
+// Returns true if it is highly unlikely that the database can recover from
+// |error|.
+SQL_EXPORT bool IsErrorCatastrophic(int error);
+
+// Log error in console in debug mode and generate a UMA histogram in release
+// mode for |error| for |UniqueT::name()|.
+// This function is templated because histograms need to be singletons. That is
+// why they are always static at the function scope. The template parameter
+// makes the compiler create unique functions that don't share the same static
+// variable.
+template <class UniqueT>
+void LogAndRecordErrorInHistogram(int error,
+                                  sql::Connection* connection) {
+  LOG(ERROR) << "sqlite error " << error
+             << ", errno " << connection->GetLastErrno()
+             << ": " << connection->GetErrorMessage();
+
+  // Trim off the extended error codes.
+  error &= 0xff;
+
+  // The histogram values from sqlite result codes currently go from 1 to 26
+  // but 50 gives them room to grow.
+  UMA_HISTOGRAM_ENUMERATION(UniqueT::name(), error, 50);
+}
+
+}  // namespace sql
+
+#endif  // SQL_ERROR_DELEGATE_UTIL_H_
diff --git a/sql/sql.gyp b/sql/sql.gyp
index 72d361c..86962b3 100644
--- a/sql/sql.gyp
+++ b/sql/sql.gyp
@@ -19,6 +19,8 @@
         'connection.cc',
         'connection.h',
         'diagnostic_error_delegate.h',
+        'error_delegate_util.cc',
+        'error_delegate_util.h',
         'init_status.h',
         'meta_table.cc',
         'meta_table.h',