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pjs/db/morkreader/nsMorkReader.cpp

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17 KiB
C++
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is the Mork Reader.
*
* The Initial Developer of the Original Code is
* Google Inc.
* Portions created by the Initial Developer are Copyright (C) 2006
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Brian Ryner <bryner@brianryner.com> (original author)
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "nsMorkReader.h"
#include "prio.h"
#include "nsNetUtil.h"
#include "nsVoidArray.h"
// A FixedString implementation that can hold 2 80-character lines
class nsCLineString : public nsFixedCString
{
public:
nsCLineString() : fixed_string_type(mStorage, sizeof(mStorage), 0) {}
explicit nsCLineString(const substring_type& str)
: fixed_string_type(mStorage, sizeof(mStorage), 0)
{
Assign(str);
}
private:
char_type mStorage[160];
};
// Convert a hex character (0-9, A-F) to its corresponding byte value.
// The character pointed to by 'c' is modified in place.
inline PRBool
ConvertChar(char *c)
{
char c1 = *c;
if ('0' <= c1 && c1 <= '9') {
*c = c1 - '0';
return PR_TRUE;
}
if ('A' <= c1 && c1 <= 'F') {
*c = c1 - 'A' + 10;
return PR_TRUE;
}
return PR_FALSE;
}
// Unescape a Mork value. Mork uses $xx escaping to encode non-ASCII
// characters. Additionally, '$' and '\' are backslash-escaped.
// The result of the unescape is in returned into aResult.
static void
MorkUnescape(const nsCSubstring &aString, nsCString &aResult)
{
PRUint32 len = aString.Length();
// We optimize for speed over space here -- size the result buffer to
// the size of the source, which is an upper bound on the size of the
// unescaped string.
// FIXME: Mork assume there will never be errors
if (!EnsureStringLength(aResult, len)) {
aResult.Truncate();
return; // out of memory.
}
char *result = aResult.BeginWriting();
const char *source = aString.BeginReading();
const char *sourceEnd = source + len;
const char *startPos = nsnull;
PRUint32 bytes;
for (; source < sourceEnd; ++source) {
char c = *source;
if (c == '\\') {
if (startPos) {
bytes = source - startPos;
memcpy(result, startPos, bytes);
result += bytes;
startPos = nsnull;
}
if (source < sourceEnd - 1) {
*(result++) = *(++source);
}
} else if (c == '$') {
if (startPos) {
bytes = source - startPos;
memcpy(result, startPos, bytes);
result += bytes;
startPos = nsnull;
}
if (source < sourceEnd - 2) {
// Would be nice to use ToInteger() here, but it currently
// requires a null-terminated string.
char c2 = *(++source);
char c3 = *(++source);
if (ConvertChar(&c2) && ConvertChar(&c3)) {
*(result++) = ((c2 << 4) | c3);
}
}
} else if (!startPos) {
startPos = source;
}
}
if (startPos) {
bytes = source - startPos;
memcpy(result, startPos, bytes);
result += bytes;
}
aResult.SetLength(result - aResult.BeginReading());
}
nsresult
nsMorkReader::Init()
{
NS_ENSURE_TRUE(mValueMap.Init(), NS_ERROR_OUT_OF_MEMORY);
NS_ENSURE_TRUE(mTable.Init(), NS_ERROR_OUT_OF_MEMORY);
return NS_OK;
}
static PLDHashOperator
DeleteStringArray(const nsCSubstring& aKey,
nsTArray<nsCString> *aData,
void *aUserArg)
{
delete aData;
return PL_DHASH_NEXT;
}
nsMorkReader::~nsMorkReader()
{
mTable.EnumerateRead(DeleteStringArray, nsnull);
}
struct AddColumnClosure
{
AddColumnClosure(nsTArray<nsMorkReader::MorkColumn> *a,
nsMorkReader::IndexMap *c)
: array(a), columnMap(c), result(NS_OK) {}
nsTArray<nsMorkReader::MorkColumn> *array;
nsMorkReader::IndexMap *columnMap;
nsresult result;
};
static PLDHashOperator
AddColumn(const nsCSubstring &id, nsCString name, void *userData)
{
AddColumnClosure *closure = static_cast<AddColumnClosure*>(userData);
nsTArray<nsMorkReader::MorkColumn> *array = closure->array;
if (!array->AppendElement(nsMorkReader::MorkColumn(id, name)) ||
!closure->columnMap->Put(id, array->Length() - 1)) {
closure->result = NS_ERROR_OUT_OF_MEMORY;
return PL_DHASH_STOP;
}
return PL_DHASH_NEXT;
}
nsresult
nsMorkReader::Read(nsIFile *aFile)
{
nsCOMPtr<nsIFileInputStream> stream =
do_CreateInstance(NS_LOCALFILEINPUTSTREAM_CONTRACTID);
NS_ENSURE_TRUE(stream, NS_ERROR_FAILURE);
nsresult rv = stream->Init(aFile, PR_RDONLY, 0, 0);
NS_ENSURE_SUCCESS(rv, rv);
mStream = do_QueryInterface(stream);
NS_ASSERTION(mStream, "file input stream must impl nsILineInputStream");
nsCLineString line;
rv = ReadLine(line);
if (!line.EqualsLiteral("// <!-- <mdb:mork:z v=\"1.4\"/> -->")) {
return NS_ERROR_FAILURE; // unexpected file format
}
IndexMap columnMap;
NS_ENSURE_TRUE(columnMap.Init(), NS_ERROR_OUT_OF_MEMORY);
while (NS_SUCCEEDED(ReadLine(line))) {
// Trim off leading spaces
PRUint32 idx = 0, len = line.Length();
while (idx < len && line[idx] == ' ') {
++idx;
}
if (idx >= len) {
continue;
}
const nsCSubstring &l = Substring(line, idx);
// Look at the line to figure out what section type this is
if (StringBeginsWith(l, NS_LITERAL_CSTRING("< <(a=c)>"))) {
// Column map. We begin by creating a hash of column id to column name.
StringMap columnNameMap;
NS_ENSURE_TRUE(columnNameMap.Init(), NS_ERROR_OUT_OF_MEMORY);
rv = ParseMap(l, &columnNameMap);
NS_ENSURE_SUCCESS(rv, rv);
// Now that we have the list of columns, we put them into a flat array.
// Rows will have value arrays of the same size, with indexes that
// correspond to the columns array. As we insert each column into the
// array, we also make an entry in columnMap so that we can look up the
// index given the column id.
mColumns.SetCapacity(columnNameMap.Count());
AddColumnClosure closure(&mColumns, &columnMap);
columnNameMap.EnumerateRead(AddColumn, &closure);
if (NS_FAILED(closure.result)) {
return closure.result;
}
} else if (StringBeginsWith(l, NS_LITERAL_CSTRING("<("))) {
// Value map
rv = ParseMap(l, &mValueMap);
NS_ENSURE_SUCCESS(rv, rv);
} else if (l[0] == '{' || l[0] == '[') {
// Table / table row
rv = ParseTable(l, columnMap);
NS_ENSURE_SUCCESS(rv, rv);
} else {
// Don't know, hopefully don't care
}
}
return NS_OK;
}
void
nsMorkReader::EnumerateRows(RowEnumerator aCallback, void *aUserData) const
{
// Constify the table values
typedef const nsDataHashtable<IDKey, const nsTArray<nsCString>* > ConstTable;
reinterpret_cast<ConstTable*>(&mTable)->EnumerateRead(aCallback,
aUserData);
}
// Parses a key/value map of the form
// <(k1=v1)(k2=v2)...>
nsresult
nsMorkReader::ParseMap(const nsCSubstring &aLine, StringMap *aMap)
{
nsCLineString line(aLine);
nsCAutoString key;
nsresult rv = NS_OK;
// If the first line is the a=c line (column map), just skip over it.
if (StringBeginsWith(line, NS_LITERAL_CSTRING("< <(a=c)>"))) {
rv = ReadLine(line);
}
for (; NS_SUCCEEDED(rv); rv = ReadLine(line)) {
PRUint32 idx = 0;
PRUint32 len = line.Length();
PRUint32 tokenStart;
while (idx < len) {
switch (line[idx++]) {
case '(':
// Beginning of a key/value pair
if (!key.IsEmpty()) {
NS_WARNING("unterminated key/value pair?");
key.Truncate(0);
}
tokenStart = idx;
while (idx < len && line[idx] != '=') {
++idx;
}
key = Substring(line, tokenStart, idx - tokenStart);
break;
case '=':
{
// Beginning of the value
if (key.IsEmpty()) {
NS_WARNING("stray value");
break;
}
tokenStart = idx;
while (idx < len && line[idx] != ')') {
if (line[idx] == '\\') {
++idx; // skip escaped ')' characters
}
++idx;
}
PRUint32 tokenEnd = NS_MIN(idx, len);
++idx;
nsCString value;
MorkUnescape(Substring(line, tokenStart, tokenEnd - tokenStart),
value);
aMap->Put(key, value);
key.Truncate(0);
break;
}
case '>':
// End of the map.
NS_WARN_IF_FALSE(key.IsEmpty(),
"map terminates inside of key/value pair");
return NS_OK;
}
}
}
// We ran out of lines and the map never terminated. This probably indicates
// a parsing error.
NS_WARNING("didn't find end of key/value map");
return NS_ERROR_FAILURE;
}
// Parses a table row of the form [123(^45^67)..]
// (row id 123 has the value with id 67 for the column with id 45).
// A '^' prefix for a column or value references an entry in the column or
// value map. '=' is used as the separator when the value is a literal.
nsresult
nsMorkReader::ParseTable(const nsCSubstring &aLine, const IndexMap &aColumnMap)
{
nsCLineString line(aLine);
const PRUint32 columnCount = mColumns.Length(); // total number of columns
PRInt32 columnIndex = -1; // column index of the cell we're parsing
// value array for the row we're parsing
nsTArray<nsCString> *currentRow = nsnull;
PRBool inMetaRow = PR_FALSE;
do {
PRUint32 idx = 0;
PRUint32 len = line.Length();
PRUint32 tokenStart, tokenEnd;
while (idx < len) {
switch (line[idx++]) {
case '{':
// This marks the beginning of a table section. There's a lot of
// junk before the first row that looks like cell values but isn't.
// Skip to the first '['.
while (idx < len && line[idx] != '[') {
if (line[idx] == '{') {
inMetaRow = PR_TRUE; // the meta row is enclosed in { }
} else if (line[idx] == '}') {
inMetaRow = PR_FALSE;
}
++idx;
}
break;
case '[':
{
// Start of a new row. Consume the row id, up to the first '('.
// Row edits also have a table namespace, separated from the row id
// by a colon. We don't make use of the namespace, but we need to
// make sure not to consider it part of the row id.
if (currentRow) {
NS_WARNING("unterminated row?");
currentRow = nsnull;
}
// Check for a '-' at the start of the id. This signifies that
// if the row already exists, we should delete all columns from it
// before adding the new values.
PRBool cutColumns;
if (idx < len && line[idx] == '-') {
cutColumns = PR_TRUE;
++idx;
} else {
cutColumns = PR_FALSE;
}
tokenStart = idx;
while (idx < len &&
line[idx] != '(' &&
line[idx] != ']' &&
line[idx] != ':') {
++idx;
}
tokenEnd = idx;
while (idx < len && line[idx] != '(' && line[idx] != ']') {
++idx;
}
if (inMetaRow) {
mMetaRow = NewVoidStringArray(columnCount);
NS_ENSURE_TRUE(mMetaRow, NS_ERROR_OUT_OF_MEMORY);
currentRow = mMetaRow;
} else {
const nsCSubstring& row = Substring(line, tokenStart,
tokenEnd - tokenStart);
if (!mTable.Get(row, &currentRow)) {
currentRow = NewVoidStringArray(columnCount);
NS_ENSURE_TRUE(currentRow, NS_ERROR_OUT_OF_MEMORY);
NS_ENSURE_TRUE(mTable.Put(row, currentRow),
NS_ERROR_OUT_OF_MEMORY);
}
}
if (cutColumns) {
// Set all of the columns to void
// (this differentiates them from columns which are empty strings).
for (PRUint32 i = 0; i < columnCount; ++i) {
currentRow->ElementAt(i).SetIsVoid(PR_TRUE);
}
}
break;
}
case ']':
// We're done with the row
currentRow = nsnull;
inMetaRow = PR_FALSE;
break;
case '(':
{
if (!currentRow) {
NS_WARNING("cell value outside of row");
break;
}
NS_WARN_IF_FALSE(columnIndex == -1, "unterminated cell?");
PRBool columnIsAtom;
if (line[idx] == '^') {
columnIsAtom = PR_TRUE;
++idx; // this is not part of the column id, advance past it
} else {
columnIsAtom = PR_FALSE;
}
tokenStart = idx;
while (idx < len && line[idx] != '^' && line[idx] != '=') {
if (line[idx] == '\\') {
++idx; // skip escaped characters
}
++idx;
}
tokenEnd = NS_MIN(idx, len);
nsCAutoString column;
const nsCSubstring &colValue =
Substring(line, tokenStart, tokenEnd - tokenStart);
if (columnIsAtom) {
column.Assign(colValue);
} else {
MorkUnescape(colValue, column);
}
if (!aColumnMap.Get(colValue, &columnIndex)) {
NS_WARNING("Column not in column map, discarding it");
columnIndex = -1;
}
}
break;
case '=':
case '^':
{
if (columnIndex == -1) {
NS_WARNING("stray ^ or = marker");
break;
}
PRBool valueIsAtom = (line[idx - 1] == '^');
tokenStart = idx - 1; // include the '=' or '^' marker in the value
while (idx < len && line[idx] != ')') {
if (line[idx] == '\\') {
++idx; // skip escaped characters
}
++idx;
}
tokenEnd = NS_MIN(idx, len);
++idx;
const nsCSubstring &value =
Substring(line, tokenStart, tokenEnd - tokenStart);
if (valueIsAtom) {
(*currentRow)[columnIndex] = value;
} else {
nsCAutoString value2;
MorkUnescape(value, value2);
(*currentRow)[columnIndex] = value2;
}
columnIndex = -1;
}
break;
}
}
} while (currentRow && NS_SUCCEEDED(ReadLine(line)));
return NS_OK;
}
nsresult
nsMorkReader::ReadLine(nsCString &aLine)
{
PRBool res;
nsresult rv = mStream->ReadLine(aLine, &res);
NS_ENSURE_SUCCESS(rv, rv);
if (!res) {
return NS_ERROR_NOT_AVAILABLE;
}
while (!aLine.IsEmpty() && aLine.Last() == '\\') {
// There is a continuation for this line. Read it and append.
nsCLineString line2;
rv = mStream->ReadLine(line2, &res);
NS_ENSURE_SUCCESS(rv, rv);
if (!res) {
return NS_ERROR_NOT_AVAILABLE;
}
aLine.Truncate(aLine.Length() - 1);
aLine.Append(line2);
}
return NS_OK;
}
void
nsMorkReader::NormalizeValue(nsCString &aValue) const
{
PRUint32 len = aValue.Length();
if (len == 0) {
return;
}
const nsCSubstring &str = Substring(aValue, 1, len - 1);
char c = aValue[0];
if (c == '^') {
if (!mValueMap.Get(str, &aValue)) {
aValue.Truncate(0);
}
} else if (c == '=') {
aValue.Assign(str);
} else {
aValue.Truncate(0);
}
}
/* static */ nsTArray<nsCString>*
nsMorkReader::NewVoidStringArray(PRInt32 aCount)
{
nsAutoPtr< nsTArray<nsCString> > array(new nsTArray<nsCString>(aCount));
NS_ENSURE_TRUE(array, nsnull);
for (PRInt32 i = 0; i < aCount; ++i) {
nsCString *elem = array->AppendElement();
NS_ENSURE_TRUE(elem, nsnull);
elem->SetIsVoid(PR_TRUE);
}
return array.forget();
}
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