Android Intent 源码学习

    private final int register_intent_filter(F filter, Iterator<String> i,
            ArrayMap<String, F[]> dest, String prefix) {
        if (i == null) {
            return 0;
        }

        int num = 0;
        while (i.hasNext()) {
            String name = i.next();
            num++;
            addFilter(dest, name, filter);
        }
        return num;
    }

    private final void addFilter(ArrayMap<String, F[]> map, String name, F filter) {
        F[] array = map.get(name);
        if (array == null) {
            array = newArray(2);
            map.put(name,  array);
            array[0] = filter;
        } else {
            final int N = array.length;
            int i = N;
            while (i > 0 && array[i-1] == null) {
                i--;
            }
            if (i < N) {
                array[i] = filter;
            } else {
                F[] newa = newArray((N*3)/2);
                System.arraycopy(array, 0, newa, 0, N);
                newa[N] = filter;
                map.put(name, newa);
            }
        }
    }

    @Override
    public List<ResolveInfo> queryIntentActivities(Intent intent,
                                                   int flags) {
        return queryIntentActivitiesAsUser(intent, flags, mContext.getUserId());
    }

    /** @hide Same as above but for a specific user */
    @Override
    public List<ResolveInfo> queryIntentActivitiesAsUser(Intent intent,
                                                   int flags, int userId) {
        try {
            return mPM.queryIntentActivities(
                intent,
                intent.resolveTypeIfNeeded(mContext.getContentResolver()),
                flags,
                userId);
        } catch (RemoteException e) {
            throw new RuntimeException("Package manager has died", e);
        }
    }

	public List<ResolveInfo> queryIntentActivities(Intent intent, String resolvedType, int flags, int userId) {
		if (!sUserManager.exists(userId))
			return Collections.emptyList();
		enforceCrossUserPermission(Binder.getCallingUid(), userId, false, "query intent activities");
		ComponentName comp = intent.getComponent();
		if (comp == null) {
			if (intent.getSelector() != null) {
				intent = intent.getSelector();
				comp = intent.getComponent();
			}
		}

		if (comp != null) {
			// Explicit的Intent，直接根据component得到对应的ActivityInfo
			final List<ResolveInfo> list = new ArrayList<ResolveInfo>(1);
			final ActivityInfo ai = getActivityInfo(comp, flags, userId);
			if (ai != null) {
				final ResolveInfo ri = new ResolveInfo();
				ri.activityInfo = ai;
				list.add(ri);
			}
			return list;
		}

		// reader
		synchronized (mPackages) {
			final String pkgName = intent.getPackage();
			if (pkgName == null) {
				// Implicit Intent
				return mActivities.queryIntent(intent, resolvedType, flags, userId);
			}
			final PackageParser.Package pkg = mPackages.get(pkgName);
			if (pkg != null) {
				// 指定了包名的Intent
				return mActivities.queryIntentForPackage(intent, resolvedType, flags, pkg.activities, userId);
			}
			return new ArrayList<ResolveInfo>();
		}
	}

		public List<ResolveInfo> queryIntent(Intent intent, String resolvedType, int flags, int userId) {
			if (!sUserManager.exists(userId))
				return null;
			mFlags = flags;
			return super.queryIntent(intent, resolvedType, (flags & PackageManager.MATCH_DEFAULT_ONLY) != 0, userId);
		}

    public List<R> queryIntent(Intent intent, String resolvedType, boolean defaultOnly,
            int userId) {
        String scheme = intent.getScheme();

        ArrayList<R> finalList = new ArrayList<R>();

        // 最多有4轮匹配操作
        F[] firstTypeCut = null;
        F[] secondTypeCut = null;
        F[] thirdTypeCut = null;
        F[] schemeCut = null;

        // If the intent includes a MIME type, then we want to collect all of
        // the filters that match that MIME type.
        if (resolvedType != null) {
            int slashpos = resolvedType.indexOf('/');
            if (slashpos > 0) {
                final String baseType = resolvedType.substring(0, slashpos);
                if (!baseType.equals("*")) {
                    if (resolvedType.length() != slashpos+2
                            || resolvedType.charAt(slashpos+1) != '*') {
                        // Not a wild card, so we can just look for all filters that
                        // completely match or wildcards whose base type matches.
                        firstTypeCut = mTypeToFilter.get(resolvedType);
                        secondTypeCut = mWildTypeToFilter.get(baseType);
                    } else {
                        // We can match anything with our base type.
                        firstTypeCut = mBaseTypeToFilter.get(baseType);
                        secondTypeCut = mWildTypeToFilter.get(baseType);
                    }
                    // Any */* types always apply, but we only need to do this
                    // if the intent type was not already */*.
                    thirdTypeCut = mWildTypeToFilter.get("*");
                } else if (intent.getAction() != null) {
                    // The intent specified any type ({@literal *}/*).  This
                    // can be a whole heck of a lot of things, so as a first
                    // cut let's use the action instead.
                    firstTypeCut = mTypedActionToFilter.get(intent.getAction());
                }
            }
        }

        // If the intent includes a data URI, then we want to collect all of
        // the filters that match its scheme (we will further refine matches
        // on the authority and path by directly matching each resulting filter).
        if (scheme != null) {
            schemeCut = mSchemeToFilter.get(scheme);
        }

        // If the intent does not specify any data -- either a MIME type or
        // a URI -- then we will only be looking for matches against empty
        // data.
        if (resolvedType == null && scheme == null && intent.getAction() != null) {
            firstTypeCut = mActionToFilter.get(intent.getAction());
        }

        FastImmutableArraySet<String> categories = getFastIntentCategories(intent);
        if (firstTypeCut != null) {
            buildResolveList(intent, categories, debug, defaultOnly,
                    resolvedType, scheme, firstTypeCut, finalList, userId);
        }
        if (secondTypeCut != null) {
            buildResolveList(intent, categories, debug, defaultOnly,
                    resolvedType, scheme, secondTypeCut, finalList, userId);
        }
        if (thirdTypeCut != null) {
            buildResolveList(intent, categories, debug, defaultOnly,
                    resolvedType, scheme, thirdTypeCut, finalList, userId);
        }
        if (schemeCut != null) {
            buildResolveList(intent, categories, debug, defaultOnly,
                    resolvedType, scheme, schemeCut, finalList, userId);
        }
        sortResults(finalList);

        return finalList;
    }