scmdiff.cpp@ 93941

Last change on this file since 93941 was 93115, checked in by vboxsync, 3 years ago
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1	/* $Id: scmdiff.cpp 93115 2022-01-01 11:31:46Z vboxsync $ */
2	/** @file
3	* IPRT Testcase / Tool - Source Code Massager.
4	*/
5
6	/*
7	* Copyright (C) 2010-2022 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*/
17
18
19	/*********************************************************************************************************************************
20	* Header Files *
21	*********************************************************************************************************************************/
22	#include <iprt/assert.h>
23	#include <iprt/ctype.h>
24	#include <iprt/message.h>
25	#include <iprt/stream.h>
26	#include <iprt/string.h>
27
28	#include "scmdiff.h"
29
30
31	/*********************************************************************************************************************************
32	* Global Variables *
33	*********************************************************************************************************************************/
34	static const char g_szTabSpaces[16+1] = " ";
35
36
37
38	/**
39	* Prints a range of lines with a prefix.
40	*
41	* @param pState The diff state.
42	* @param chPrefix The prefix.
43	* @param pStream The stream to get the lines from.
44	* @param iLine The first line.
45	* @param cLines The number of lines.
46	*/
47	static void scmDiffPrintLines(PSCMDIFFSTATE pState, char chPrefix, PSCMSTREAM pStream, size_t iLine, size_t cLines)
48	{
49	while (cLines-- > 0)
50	{
51	SCMEOL enmEol;
52	size_t cchLine;
53	const char *pchLine = ScmStreamGetLineByNo(pStream, iLine, &cchLine, &enmEol);
54
55	RTStrmPutCh(pState->pDiff, chPrefix);
56	if (pchLine && cchLine)
57	{
58	if (!pState->fSpecialChars)
59	RTStrmWrite(pState->pDiff, pchLine, cchLine);
60	else
61	{
62	size_t offVir = 0;
63	const char *pchStart = pchLine;
64	const char pchTab = (const char )memchr(pchLine, '\t', cchLine);
65	while (pchTab)
66	{
67	RTStrmWrite(pState->pDiff, pchStart, pchTab - pchStart);
68	offVir += pchTab - pchStart;
69
70	size_t cchTab = pState->cchTab - offVir % pState->cchTab;
71	switch (cchTab)
72	{
73	case 1: RTStrmPutStr(pState->pDiff, "."); break;
74	case 2: RTStrmPutStr(pState->pDiff, ".."); break;
75	case 3: RTStrmPutStr(pState->pDiff, "[T]"); break;
76	case 4: RTStrmPutStr(pState->pDiff, "[TA]"); break;
77	case 5: RTStrmPutStr(pState->pDiff, "[TAB]"); break;
78	default: RTStrmPrintf(pState->pDiff, "[TAB%.*s]", cchTab - 5, g_szTabSpaces); break;
79	}
80	offVir += cchTab;
81
82	/* next */
83	pchStart = pchTab + 1;
84	pchTab = (const char *)memchr(pchStart, '\t', cchLine - (pchStart - pchLine));
85	}
86	size_t cchLeft = cchLine - (pchStart - pchLine);
87	if (cchLeft)
88	RTStrmWrite(pState->pDiff, pchStart, cchLeft);
89	}
90	}
91
92	if (!pState->fSpecialChars)
93	RTStrmPutCh(pState->pDiff, '\n');
94	else if (enmEol == SCMEOL_LF)
95	RTStrmPutStr(pState->pDiff, "[LF]\n");
96	else if (enmEol == SCMEOL_CRLF)
97	RTStrmPutStr(pState->pDiff, "[CRLF]\n");
98	else
99	RTStrmPutStr(pState->pDiff, "[NONE]\n");
100
101	iLine++;
102	}
103	}
104
105
106	/**
107	* Reports a difference and propels the streams to the lines following the
108	* resync.
109	*
110	*
111	* @returns New pState->cDiff value (just to return something).
112	* @param pState The diff state. The cDiffs member will be
113	* incremented.
114	* @param cMatches The resync length.
115	* @param iLeft Where the difference starts on the left side.
116	* @param cLeft How long it is on this side. ~(size_t)0 is used
117	* to indicate that it goes all the way to the end.
118	* @param iRight Where the difference starts on the right side.
119	* @param cRight How long it is.
120	*/
121	static size_t scmDiffReport(PSCMDIFFSTATE pState, size_t cMatches,
122	size_t iLeft, size_t cLeft,
123	size_t iRight, size_t cRight)
124	{
125	/*
126	* Adjust the input.
127	*/
128	if (cLeft == ~(size_t)0)
129	{
130	size_t c = ScmStreamCountLines(pState->pLeft);
131	if (c >= iLeft)
132	cLeft = c - iLeft;
133	else
134	{
135	iLeft = c;
136	cLeft = 0;
137	}
138	}
139
140	if (cRight == ~(size_t)0)
141	{
142	size_t c = ScmStreamCountLines(pState->pRight);
143	if (c >= iRight)
144	cRight = c - iRight;
145	else
146	{
147	iRight = c;
148	cRight = 0;
149	}
150	}
151
152	/*
153	* Print header if it's the first difference
154	*/
155	if (!pState->cDiffs)
156	RTStrmPrintf(pState->pDiff, "diff %s %s\n", pState->pszFilename, pState->pszFilename);
157
158	/*
159	* Emit the change description.
160	*/
161	char ch = cLeft == 0
162	? 'a'
163	: cRight == 0
164	? 'd'
165	: 'c';
166	if (cLeft > 1 && cRight > 1)
167	RTStrmPrintf(pState->pDiff, "%zu,%zu%c%zu,%zu\n", iLeft + 1, iLeft + cLeft, ch, iRight + 1, iRight + cRight);
168	else if (cLeft > 1)
169	RTStrmPrintf(pState->pDiff, "%zu,%zu%c%zu\n", iLeft + 1, iLeft + cLeft, ch, iRight + 1);
170	else if (cRight > 1)
171	RTStrmPrintf(pState->pDiff, "%zu%c%zu,%zu\n", iLeft + 1, ch, iRight + 1, iRight + cRight);
172	else
173	RTStrmPrintf(pState->pDiff, "%zu%c%zu\n", iLeft + 1, ch, iRight + 1);
174
175	/*
176	* And the lines.
177	*/
178	if (cLeft)
179	scmDiffPrintLines(pState, '<', pState->pLeft, iLeft, cLeft);
180	if (cLeft && cRight)
181	RTStrmPrintf(pState->pDiff, "---\n");
182	if (cRight)
183	scmDiffPrintLines(pState, '>', pState->pRight, iRight, cRight);
184
185	/*
186	* Reposition the streams (safely ignores return value).
187	*/
188	ScmStreamSeekByLine(pState->pLeft, iLeft + cLeft + cMatches);
189	ScmStreamSeekByLine(pState->pRight, iRight + cRight + cMatches);
190
191	pState->cDiffs++;
192	return pState->cDiffs;
193	}
194
195	/**
196	* Helper for scmDiffCompare that takes care of trailing spaces and stuff
197	* like that.
198	*/
199	static bool scmDiffCompareSlow(PSCMDIFFSTATE pState,
200	const char *pchLeft, size_t cchLeft, SCMEOL enmEolLeft,
201	const char *pchRight, size_t cchRight, SCMEOL enmEolRight)
202	{
203	if (pState->fIgnoreTrailingWhite)
204	{
205	while (cchLeft > 0 && RT_C_IS_SPACE(pchLeft[cchLeft - 1]))
206	cchLeft--;
207	while (cchRight > 0 && RT_C_IS_SPACE(pchRight[cchRight - 1]))
208	cchRight--;
209	}
210
211	if (pState->fIgnoreLeadingWhite)
212	{
213	while (cchLeft > 0 && RT_C_IS_SPACE(*pchLeft))
214	pchLeft++, cchLeft--;
215	while (cchRight > 0 && RT_C_IS_SPACE(*pchRight))
216	pchRight++, cchRight--;
217	}
218
219	if ( cchLeft != cchRight
220	\|\| (enmEolLeft != enmEolRight && !pState->fIgnoreEol)
221	\|\| memcmp(pchLeft, pchRight, cchLeft))
222	return false;
223	return true;
224	}
225
226	/**
227	* Compare two lines.
228	*
229	* @returns true if the are equal, false if not.
230	*/
231	DECLINLINE(bool) scmDiffCompare(PSCMDIFFSTATE pState,
232	const char *pchLeft, size_t cchLeft, SCMEOL enmEolLeft,
233	const char *pchRight, size_t cchRight, SCMEOL enmEolRight)
234	{
235	if ( cchLeft != cchRight
236	\|\| (enmEolLeft != enmEolRight && !pState->fIgnoreEol)
237	\|\| memcmp(pchLeft, pchRight, cchLeft))
238	{
239	if ( pState->fIgnoreTrailingWhite
240	\|\| pState->fIgnoreLeadingWhite)
241	return scmDiffCompareSlow(pState,
242	pchLeft, cchLeft, enmEolLeft,
243	pchRight, cchRight, enmEolRight);
244	return false;
245	}
246	return true;
247	}
248
249	/**
250	* Compares two sets of lines from the two files.
251	*
252	* @returns true if they matches, false if they don't.
253	* @param pState The diff state.
254	* @param iLeft Where to start in the left stream.
255	* @param iRight Where to start in the right stream.
256	* @param cLines How many lines to compare.
257	*/
258	static bool scmDiffCompareLines(PSCMDIFFSTATE pState, size_t iLeft, size_t iRight, size_t cLines)
259	{
260	for (size_t iLine = 0; iLine < cLines; iLine++)
261	{
262	SCMEOL enmEolLeft;
263	size_t cchLeft;
264	const char *pchLeft = ScmStreamGetLineByNo(pState->pLeft, iLeft + iLine, &cchLeft, &enmEolLeft);
265
266	SCMEOL enmEolRight;
267	size_t cchRight;
268	const char *pchRight = ScmStreamGetLineByNo(pState->pRight, iRight + iLine, &cchRight, &enmEolRight);
269
270	if (!scmDiffCompare(pState, pchLeft, cchLeft, enmEolLeft, pchRight, cchRight, enmEolRight))
271	return false;
272	}
273	return true;
274	}
275
276
277	/**
278	* Resynchronize the two streams and reports the difference.
279	*
280	* Upon return, the streams will be positioned after the block of @a cMatches
281	* lines where it resynchronized them.
282	*
283	* @returns pState->cDiffs (just so we can use it in a return statement).
284	* @param pState The state.
285	* @param cMatches The number of lines that needs to match for the
286	* stream to be considered synchronized again.
287	*/
288	static size_t scmDiffSynchronize(PSCMDIFFSTATE pState, size_t cMatches)
289	{
290	size_t const iStartLeft = ScmStreamTellLine(pState->pLeft) - 1;
291	size_t const iStartRight = ScmStreamTellLine(pState->pRight) - 1;
292	Assert(cMatches > 0);
293
294	/*
295	* Compare each new line from each of the streams will all the preceding
296	* ones, including iStartLeft/Right.
297	*/
298	for (size_t iRange = 1; ; iRange++)
299	{
300	/*
301	* Get the next line in the left stream and compare it against all the
302	* preceding lines on the right side.
303	*/
304	SCMEOL enmEol;
305	size_t cchLine;
306	const char *pchLine = ScmStreamGetLineByNo(pState->pLeft, iStartLeft + iRange, &cchLine, &enmEol);
307	if (!pchLine)
308	return scmDiffReport(pState, 0, iStartLeft, ~(size_t)0, iStartRight, ~(size_t)0);
309
310	for (size_t iRight = cMatches - 1; iRight < iRange; iRight++)
311	{
312	SCMEOL enmEolRight;
313	size_t cchRight;
314	const char *pchRight = ScmStreamGetLineByNo(pState->pRight, iStartRight + iRight,
315	&cchRight, &enmEolRight);
316	if ( scmDiffCompare(pState, pchLine, cchLine, enmEol, pchRight, cchRight, enmEolRight)
317	&& scmDiffCompareLines(pState,
318	iStartLeft + iRange + 1 - cMatches,
319	iStartRight + iRight + 1 - cMatches,
320	cMatches - 1)
321	)
322	return scmDiffReport(pState, cMatches,
323	iStartLeft, iRange + 1 - cMatches,
324	iStartRight, iRight + 1 - cMatches);
325	}
326
327	/*
328	* Get the next line in the right stream and compare it against all the
329	* lines on the right side.
330	*/
331	pchLine = ScmStreamGetLineByNo(pState->pRight, iStartRight + iRange, &cchLine, &enmEol);
332	if (!pchLine)
333	return scmDiffReport(pState, 0, iStartLeft, ~(size_t)0, iStartRight, ~(size_t)0);
334
335	for (size_t iLeft = cMatches - 1; iLeft <= iRange; iLeft++)
336	{
337	SCMEOL enmEolLeft;
338	size_t cchLeft;
339	const char *pchLeft = ScmStreamGetLineByNo(pState->pLeft, iStartLeft + iLeft,
340	&cchLeft, &enmEolLeft);
341	if ( scmDiffCompare(pState, pchLeft, cchLeft, enmEolLeft, pchLine, cchLine, enmEol)
342	&& scmDiffCompareLines(pState,
343	iStartLeft + iLeft + 1 - cMatches,
344	iStartRight + iRange + 1 - cMatches,
345	cMatches - 1)
346	)
347	return scmDiffReport(pState, cMatches,
348	iStartLeft, iLeft + 1 - cMatches,
349	iStartRight, iRange + 1 - cMatches);
350	}
351	}
352	}
353
354	/**
355	* Creates a diff of the changes between the streams @a pLeft and @a pRight.
356	*
357	* This currently only implements the simplest diff format, so no contexts.
358	*
359	* Also, note that we won't detect differences in the final newline of the
360	* streams.
361	*
362	* @returns The number of differences.
363	* @param pszFilename The filename.
364	* @param pLeft The left side stream.
365	* @param pRight The right side stream.
366	* @param fIgnoreEol Whether to ignore end of line markers.
367	* @param fIgnoreLeadingWhite Set if leading white space should be ignored.
368	* @param fIgnoreTrailingWhite Set if trailing white space should be ignored.
369	* @param fSpecialChars Whether to print special chars in a human
370	* readable form or not.
371	* @param cchTab The tab size.
372	* @param pDiff Where to write the diff.
373	*/
374	size_t ScmDiffStreams(const char *pszFilename, PSCMSTREAM pLeft, PSCMSTREAM pRight, bool fIgnoreEol,
375	bool fIgnoreLeadingWhite, bool fIgnoreTrailingWhite, bool fSpecialChars,
376	size_t cchTab, PRTSTREAM pDiff)
377	{
378	#ifdef RT_STRICT
379	ScmStreamCheckItegrity(pLeft);
380	ScmStreamCheckItegrity(pRight);
381	#endif
382
383	/*
384	* Set up the diff state.
385	*/
386	SCMDIFFSTATE State;
387	State.cDiffs = 0;
388	State.pszFilename = pszFilename;
389	State.pLeft = pLeft;
390	State.pRight = pRight;
391	State.fIgnoreEol = fIgnoreEol;
392	State.fIgnoreLeadingWhite = fIgnoreLeadingWhite;
393	State.fIgnoreTrailingWhite = fIgnoreTrailingWhite;
394	State.fSpecialChars = fSpecialChars;
395	State.cchTab = cchTab;
396	State.pDiff = pDiff;
397
398	/*
399	* Compare them line by line.
400	*/
401	ScmStreamRewindForReading(pLeft);
402	ScmStreamRewindForReading(pRight);
403	const char *pchLeft;
404	const char *pchRight;
405
406	for (;;)
407	{
408	SCMEOL enmEolLeft;
409	size_t cchLeft;
410	pchLeft = ScmStreamGetLine(pLeft, &cchLeft, &enmEolLeft);
411
412	SCMEOL enmEolRight;
413	size_t cchRight;
414	pchRight = ScmStreamGetLine(pRight, &cchRight, &enmEolRight);
415	if (!pchLeft \|\| !pchRight)
416	break;
417
418	if (!scmDiffCompare(&State, pchLeft, cchLeft, enmEolLeft, pchRight, cchRight, enmEolRight))
419	scmDiffSynchronize(&State, 3);
420	}
421
422	/*
423	* Deal with any remaining differences.
424	*/
425	if (pchLeft)
426	scmDiffReport(&State, 0, ScmStreamTellLine(pLeft) - 1, ~(size_t)0, ScmStreamTellLine(pRight), 0);
427	else if (pchRight)
428	scmDiffReport(&State, 0, ScmStreamTellLine(pLeft), 0, ScmStreamTellLine(pRight) - 1, ~(size_t)0);
429
430	/*
431	* Report any errors.
432	*/
433	if (RT_FAILURE(ScmStreamGetStatus(pLeft)))
434	RTMsgError("Left diff stream error: %Rrc\n", ScmStreamGetStatus(pLeft));
435	if (RT_FAILURE(ScmStreamGetStatus(pRight)))
436	RTMsgError("Right diff stream error: %Rrc\n", ScmStreamGetStatus(pRight));
437
438	return State.cDiffs;
439	}
440

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source: vbox/trunk/src/bldprogs/scmdiff.cpp@ 93941

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